UDF DESCRIPTION DOCUMENT
 
Rev. 1.4
 
02/03/99
 
 

 

Revision History

 

Rev 0         7/10/98 Initial release

 

Rev 1         9/10/98 Major revision, transferred to Word document

 

Rev 1.1     9/22/98 Page numbers, table of contents, section 4.5 and table 4.5-2

 

Rev 1.2     10/14/98 Figure 2.1-1 and description updated.

                Note on B-weight added to top of p32.

 

Rev 1.3     10/30/98 Reformat for HTML, port to website
 

Rev 1.4      02/03/99        Fix unreadable figures

 

 
Table of Contents

Table of Contents *

1.0 PURPOSE *

2.0 OVERVIEW *

2.1 PROCESSING OVERVIEW *

Figure 2.1-1 UMd ACE/ULEIS Data Processing Overview *

2.2 SCIENCE DATA RECORD *

Figure 2.2-1 ULEIS SDR Format in ACE S/C Telemetry Frame Structure *

Figure 2.2-2 Uleis Data Timing *

2.3 LEVEL-1 DATA FORMAT *

2.4 TIME *

 3.0 UDF STRUCTURE * 3.1 PROCESSING *

Figure 3.1-1 *

3.2 STRUCTURE *

Table 3.2-1 UDF File Structure *

Table 3.2-2 File Header *

Table 3.2-3 Science Data Record Structure *

Table 3.2-4 Summary of Record IDs *

 4.0 RECORD STRUCTURE – LEVEL-1 DATA * 4.1 FILE HEADER *

Table 4.1-1 File Header Record Format ( Rec. ID = 99) *

4.2 SCIENCE DATA RECORD HEADER *

Table 4.2-1 SDR Header Record Format ( Rec. ID = 1) *

4.3 PULSE HEIGHT EVENT DATA *

Table 4.3-1 PHA Record Structures (Rec ID = 2) *

Table 4.3-2 PHA Packing Scheme *

Table 4.3-3 PHA Status 1 Definition *

Table 4.3-4 PHA Status 2 Definition *

4.4 SINGLE SPIN MATRIX RATES *

Table 4.4-1 Single Spin Matrix Rate Data Block (Rec ID = 3) *

Table 4.4-2 Single Spin Matrix Spin Record Structure *

4.5 SPIN-PAIR MATRIX RATES *

Table 4.5-1 Spin-Pair Matrix Rate Data Block (Rec ID = 4) *

Table 4.5-2a Spin-Pair Matrix Rate Record Structure: Launch – Feb 17 1998 *

Table 4.5-2b Spin-Pair Matrix Rate Record Structure: Feb 18 1998 - present *

4.6 DISCRIMINATOR RATES *

Table 4.6-1 Discriminator Rate Data Block (Rec ID = 5) *

Table 4.6-2 Discriminator Rate Record Format *

4.7 STATUS & INSTRUMENT HOUSEKEEPING *

Table 4.7-1 Status Data Block (Record ID = 6) *

Table 4.7-2 Status Block Record Format *

Table 4.7-3 Status Trailer Record Format *

Table 4.7-4 ULEIS Housekeeping Detail *

4.8 S/C HOUSEKEEPING *

Table 4.8-1 S/C HSKP Record Format *

5.1 FIVE-MINUTE AVERAGE BROWSE DATA *

5.1.1 MAGNETOMETER 5-MINUTE AVERAGE BROWSE *

5.1.2 SEPICA 5-MINUTE AVERAGE BROWSE *

5.1.3 EPAM 5-MINUTE AVERAGE BROWSE *

5.1.4 ULEIS 5-MINUTE AVERAGE BROWSE *

5.1.5 SWEPAM 5-MINUTE AVERAGE BROWSE *

5.2 ONE-HOUR AVERAGE BROWSE *

5.2.1 CRIS 1-HOUR AVERAGE BROWSE *

5.2.2 SIS 1-HOUR AVERAGE BROWSE *
  1.0 PURPOSE

 

The purpose of this document is to provide the detailed information needed to read the ACE/ULEIS level 1.5 data files (UDF) produced at UMd. For information on commanding and S/C data formats, see "ULEIS: Flight Software System Users Guide", JHU/APL publication SRS-084-97.

 

 

2.0 OVERVIEW

 

2.1 PROCESSING OVERVIEW

 

Processing of UMd ACE/ULEIS data is sketched in Fig. 2.1-1. Data is broadcast from the ACE satellite, arriving eventually at GSFC where raw data is converted to Level_0 data and is passed on to Caltech.

Figure 2.1-1 UMd ACE/ULEIS Data Processing Overview

 

At Caltech data is taken from packetized format and put into HDF files on 24-hour boundaries sorted by instrument and put in time order. This is Level_1 data and is distributed to investigators over FTP and via CD-ROMs.

 

As HDF is not a useful format for retrieving ULEIS data, the Level_1 data is immediately resorted into science data records and stored as UDFs. Time and position data is taken from the ancillary HDF data files at Caltech and put in UDF headers. The bare UDFs are merged with browse data from a separate file and the combined file is archived for later use. Occupying a processing level between the Level_1 data from Caltech and the Level_2 data products, the UDFs can be described as Level _1.5 data.

 

2.2 SCIENCE DATA RECORD

 

A science data record (SDR) consists of the collected ULEIS data for a period of ten consecutive spins. (A spin period is approximately 12 seconds). The SDR begins and ends on a S/C sun pulse but its readout occurs over 8 S/C telemetry major frames, beginning and ending on a 8xMajFrPulse. The distribution of the data in S/C telemetry frames is shown in Fig. 2.2-1. In this figure each line represents one major frame and the frames are synchronized to the 8xMajFr pulse. Science records appear one every 8 major S/C frames with no gaps, but they do not represent 100% of the data collected by the sensor: there is typically a dropped spin between SDRs to accommodate the different periods of readout and S/C spin. This timing is shown in more detail in Fig. 2.2-2.

 

Figure 2.2-1 ULEIS SDR Format in ACE S/C Telemetry Frame Structure
 
  Figure 2.2-2 Uleis Data Timing
 

2.3 LEVEL-1 DATA FORMAT

 

 

TBS

 

 

 

 

 

 2.4 TIME

 

Time on the S/C is counted in Minor Frames with 1 minor frame = 1 second, with some small, variable error. S/C time is the number of minor frames since the S/C data system was turned on just after launch. S/C time is an integer and by itself allows calculation of time at best to the nearest second.

 

The ACE Epoch is defined as Midnight of Jan 1 1996. Approximate ACEepoch time can be obtained by adding 52,069,705.0 to the S/C time. Due to accumulated errors and drifts in the S/C clock oscillator, this approximate time will be off GMT by several seconds. Correct ACEepoch time is obtained by multiplying the S/C clock by a daily correction factor and adding a daily offset before adding in the large offset as above. The daily factor and offset are incorporated in the ancillary data file ACE_ANCIL.HDF available via FTP or CD-ROM from Caltech. The work of performing the conversion of S/C time to ACEepoch time is performed by a C routine "SCclock_to_ACEepoch()" which is supplied by Caltech as part of the file "ancil_subs.c"

 

All ULEIS data is tagged with the "Output Time" which is the S/C time of the 8xMajFrPulse at the beginning of the readout of the science record containing the ULEIS data. Actual collection of the data of course occurred at a somewhat earlier time. The ULEIS DPU begins a Science Data Record on a Sun Pulse and records the minor frame count associated with this sun pulse in the trailer data as "Spin1MinFrCnt". We can calculate the S/C time of the beginning of the SDR in the DPU by taking the Output time, subtracting 128 to get to the start of the previous 8xMajFr cycle and adding in Spin1MinFrCnt to get to the sun pulse. Caltech does this for us and calls it the "Collect Time". Unfortunately, Caltech mis-calculated this time in early versions of the data (before v2-5) so we now perform the computation ourselves and use the result in the calculation of ACEepoch time. It is this latter time, supplied at the beginning of each SDR, which should be used in time calculations for the data. When the time_fix_flag in the SDR Header is 0, the ACEepoch time is good to the nearest second. Times for individual rates or events can be determined by adding their spin and sector times to the ACEepoch: 12 seconds/spin and 1.5 seconds/sector.

 

 

3.0 UDF STRUCTURE

 

3.1 PROCESSING

 

As detailed above, Level_1 data is organized by time: one L1 file per day starting at or near 00:00:00 and continuing through 23:59:59. UDFs are similarly organized, one UDF being produced from each L1 data file.

 

UDF files are named for the date of the included data and the version number of the software used to produce it:

 

ULyyyy_ddd.Pxx

 

ULyyyy_ddd.Rxx

Where yyyy =4-digit year

ddd = 3-digit day of year

xx = 2-digit version number

.Pxx files include all data

.Rxx files omit the PHA event data

 

The "version number" is the major version number of the program PROCESS_L1 that is used to generate the UDFs from the L1 data files.

 

A diagram of the UDF processing is shown in Fig. 3.1-1.

 

 


F
Figure 3.1-1

 

3.2 STRUCTURE

 

UDFs are unformatted FORTRAN binary files containing a day’s ULEIS data organized as a sequence of Science Data Records. The organization of a UDF is shown in Table 3.2-1.

 

The file begins with a File Header documenting the elements used in producing the file. Next come a series of Science Data Records and finally the end-of-file. In a typical complete day of data there will be 675 science records (86400 sec/day and 128 sec/SDR).

 

Table 3.2-1 UDF File Structure
 
Item #
Item
1 File Header
2 Science Data Record #1
3 Science Data Record #2
4 Science Data Record #3
… …
N+1 Science Data Record #N
N+2 End of File
 

 

A more detailed picture of the UDF structure is given in Tables 3.2-2 and 3.2-3.

 

Table 3.2-2 shows the header with its 2 constituent records: a 1-byte Record ID (value = 99 for this data type) and a 16-byte File Header. Details of the file header structure are given below in section 4.

 

Table 3.2-2 File Header
 
Rec # Contents Description Length (bytes) Comment
1 "99" File Header Record ID 1
2 Data File Header 16
 

 

Table 3.2-3 shows a complete science record broken into 14 data types each preceded by its own Record ID. Record Ids are summarized below in Table 3.2-4.

 

Table 3.2-3 Science Data Record Structure
 
Rec. # Contents Description Length (bytes) Comment
1
"1"
 Header Rec ID
1 
  
2
data
Header
54 
  
3
"8"
 Mag Browse Rec ID
1 
 Present only of B_Weight>1
4
data
5-min Mag Browse
18 
  
5
"9"
 SEPICA Browse ID
1 
 Present only if SEP LT>0
6
data
5-min SEP Brwse
40 
  
7
"10"
 EPAM Browse Rec ID
1 
 Present only if EPAM LT >0
8
data
5-min EPAM Brwse
36 
  
9
"11"
 ULEIS Brwse Rec ID
1 
 Present only if ULEIS LT>0
10
data
5-min UL Brwse
44 
  
11
"12"
 SWEPAM Brwse Rec ID
1 
 Present only if SWE wgt >1
12
data
5-min SWE Brwse
24 
  
13
"13"
 CRIS Browse Rec ID
1 
  
14
data
1-hr CRIS Brwse
56 
  
15
"14"
 SIS Browse Rec ID
1 
  
16
data
1-hr SIS Brwse
20 
  
17
"2"
 PHA Events Rec ID
1 
 Used only if pha events present
18
npha
#of PHA records 
2 
 0<npha
19
data
Block of packed pha events
22n 
 Npha records at 1 pha event per record
19+n
"3"
 1-spin MRate Rec ID
1 
  
20+n
data
Block of single-spin matrix rate data
36*80 
 80 records of 34 compressed matrix rates
100+n
"4"
 2-spin MRate Rec ID
1 
  
101+n
data
Block of double-spin matrix rate data
44*40 
 40 records of 42 compressed matrix rates
141+n
"5"
 Disc Rate Rec ID
1 
  
142+n
data
Block of discriminator rates data
34*40 
 40 records of 16 compressed discriminator rates
182+n
"6"
 Status Rec ID
1 
  
183+n
data
Status Block
112 
  
184+n
data
Status Trailer
128 
  
185+n
"7"
 HSKP Rec ID
1 
  
186+n
data
HSKP data
682 
  
187+n
"-1"
 End of Sci Record
1 
 

Note: n = number of PHA events in the science record = npha

 

 

Table 3.2-4 Summary of Record IDs
 
Rec ID Value
Data Type
1
 SDR Header
2
 PHA Events
3
 Matrix Rates Accumulated over 1 Spin
4
 Matrix Rates Accumulated over 2 Spins
5
 Discriminator Rates
6
 Status
7
 HSKP
8
 Magnetometer 5-Min Ave Browse
9
 SEPICA 5-Min Average Browse
10
 EPAM 5-Min Average Browse
11
 ULEIS 5-Min Average Browse
12
 SWEPAM 5-Min Average Browse
13
 CRIS 1-hour Average Browse
14
 SIS 1-hour Average Browse
99
 File Header
-1
 End of Science Record Marker
 

 

 

 

4.0 RECORD STRUCTURE – LEVEL-1 DATA

 

This section gives details of the structures of the data types listed above with record Ids from 1 through 7. This covers all the items included in the LEVEL_1 data files from Caltech. Browse data is considered below in section 5.

4.1 FILE HEADER

 

The detailed structure of the 16-byte File Header is shown in Table 4.1-1. The file header is read out as a single record.

 

Table 4.1-1 File Header Record Format ( Rec. ID = 99)
 
Item Bits Name Comment Type
1 8  PROCESS_L1, Major Rev # byte
2 8  PROCESS_L1, Minor Rev # byte
3 8  C modules, Major Rev # Caltech-supplied code byte
4 8  C modules, Minor Rev # byte
5 8  Data: Major Rev # Encoded in Lev 1 Data file names byte
6 8  Data: Minor Rev # byte
7 8  Spare byte
8 8  Spare byte
9 8  Spare byte
10 8  Spare byte
11 8  Spare byte
12 8  Spare byte
13 8  Spare byte
14 8  Spare byte
15 8  Spare byte
16 8  Spare byte
 

 

4.2 SCIENCE DATA RECORD HEADER

 

The detailed structure of the 54-byte Science Data Record Header is shown in Table 4.2-1. The header is read out as a single record.

 

Referring to Table 4.2-1, the ACEepoch, Collect time and Output time are discussed above in section II.

Attitude, Position and Velocity vectors are passed on from the ancillary data. No checking or processing is performed on them at this time. A quality flag is available for the attitude data but is ignored by the current software and is not in the header. For future reference, the flag has the following properties:

 
 
Flag = -1
clock out of bounds
Attitude data wrong
Flag = 0
OK
Attitude data correct
Flag= +1
maneuver in progress
Attitude data suspect
 

The QAC is a bit appearing in each minor frame of data which is set if there are any known problems with the data in that minor frame (e.g. data missing, data out of sync, etc.). QAC_Count is the number of such bits set in a given Science Record. The number may be as high as 128. The preferred value is 0.

 

The ULEIS DPU calculates a checksum for the entire data record and includes it in the status trailer at the end of the SDR. Caltech generates a similar checksum on the received data and compares it with the DPU’s value. The result is a check sum flag (Chk_sum_flag), equal to zero if the transmitted and received checksums match and to one if they differ.

 

As the ACEepoch time calculation depends on several data items being received correctly, there are a number of ways it can go wrong. As long as there are no indications of bad data, various data are consistent with each other and the resulting ACEepoch is consistent with the ones that came before, the Time_fix_flag is set to zero. Here the time data is assumed to be good and the ACEepoch calculation is performed straightforwardly. The resulting ACEepoch is good to the nearest second. If however, the QAC or CHK_SUM flag is non zero, or the output time varies too much from its predecessor, or the Spin1_min_fr_cnt is too large, the time data is assumed to be bad and an attempt is made to correct it. This is done primarily by bringing the bad or missing data into alignment with its preceding values. For these cases the Time_fix_flag is set to a value greater than zero indicating that the ACEepoch time may be off from a couple of seconds to as much as a spin.

 

Table 4.2-1 SDR Header Record Format ( Rec. ID = 1)
 
Item Bits Name Comment Type
1 32 ACE_epoch collect time in seconds since Jan1 96 int*4
2 32 Attitude: R component s/c attitude in RTN coordinates real*4
3 32 Attitude: T component real*4
4 32 Attitude: N component real*4
5 32 Position: X component s/c position, km, GSE coordinates real*4
6 32 Position: Y component real*4
7 32 Position: Z component real*4
8 32 Velocity: X component s/c velocity, km/s, in GSE coordinates real*4
9 32 Velocity: Y component real*4
10 32 Velocity: Z component real*4
11 32 collect time SC time (minor frames since launch) int*4
12 32 output time SC time (minor frames since launch) int*4
13 32 QAC_Count # of minor frames with QAC set in SDR int*4
14 8 chk_sum_flag 0=chk sums matched, 1 = chk sum error byte
15 8 time_fix_flag 0=time ok, 1=time problem had to be fixed byte
 

 

4.3 PULSE HEIGHT EVENT DATA

 

As is shown in Table 3.2-3 above, the PHA data for a given SDR are arranged as an event-count record, "NPHA", followed by the events themselves, one event per record.

 

The detailed structures of the 2-byte NPHA record and the 22-byte PHA Data records are given in Table 4.3-1. Each packed event contains 11 integer*2 words whose contents are arranged as in Table 4.3-2. In this table, S1 is the START1 wedge located at the front of the telescope. The Wedge, Strip and Zigzag are the 12-bit position signals from this wedge. Similarly, S2 is the START2 or middle wedge. STOP is the Stop wedge at the rear of the telescope. The SSD E is the energy signal associated with this event, selected from among the signals from the seven solid-state detectors. TOF1 is the time of flight between START 1 and STOP, and TOF2 is the time of flight from START2 and STOP. Status words 1 and 2 contain the flags associated with the event. They are defined in Tables 4.3-3 and 4.3-4. The spin and the sector indicate when the event was processed inside the DPU (a few milliseconds after detection in the telescope). The spin is the spin number 0-9 within the science data record. The sector is 0-15 as opposed to sectors 0-7 for rates.

RATE Sector = INT(PHA Sector / 2)

In Table 4.3-2, the L and H are used to denote the low-order and high order portions of a 12-bit word when that word has been broken up. In each entity, the less-significant bits are at the right end.

 

Record ID 2 and the associated PHA data appears only in .Pxx UDFs and then only in those SDRs for which NPHA > 0.

 

Table 4.3-1 PHA Record Structures (Rec ID = 2)

NPHA Record
 
Item # Bits Name Comment Type
1 16 NPHA # of PHA events in SDR Int*2
 

Event Record
 
Item # Bits Name Comment Type
1 16 Packed PHA word 1 See table 4.3-2 int*2
2 16 Packed PHA word 2 int*2
3 16 Packed PHA word 3 int*2
4 16 Packed PHA word 4 int*2
5 16 Packed PHA word 5 int*2
6 16 Packed PHA word 6 int*2
7 16 Packed PHA word 7 int*2
8 16 Packed PHA word 8 int*2
9 16 Packed PHA word 9 int*2
10 16 Packed PHA word 10 int*2
11 16 Packed PHA word 11 int*2
 

Table 4.3-2 PHA Packing Scheme
 
Name 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Word 1 S1 Strip (L) S1 Wedge
Word 2 S1 Zigzag (L) S1 Strip (H)
Word 3 S2 Wedge S1 Zig (H)
Word 4 S2 Zig (L) S2 Strip
Word 5 STOP Wedge (L) S2 Zig (H)
Word 6 STOP Strip STOP Wedge (H)
Word 7 SSD E (L) STOP Zigzag
Word 8 TOF1 (L) SSD E (H)
Word 9 TOF 2 TOF1 (H)
Word 10 Status2 (L) Status 1
Word 11 Spin Sector Status 2 (H)
 

Table 4.3-3 PHA Status 1 Definition
 
Bit # Normal Mode Cal Mode
11 (msb) HAZ CE11
10 LA1 CE10
9 LA0 CE9
8 SA1 CE8
7 SA0 CE7
6 D7 CE6
5 D6 CE5
4 D5 CE4
3 D4 CE3
2 D3 CE2
1 D2 CE1
0 (lsb) D1 CE0
 

Table 4.3-4 PHA Status 2 Definition
 
Bit # Normal Mode Cal Mode
11 (msb) 0 SSD ID 2
10 0 SSD ID 1
9 Box Number 5 SSD ID 0
8 Box Number 4 ES
7 Box Number 3 CAL STEP 2
6 Box Number 2 CAL STEP 1
5 Box Number 1 CAL STEP 0
4 Box Number 0 CM
3 CO CO
2 ES 0
1 TOF2 TOF2
0 (lsb) TOF1 TOF1
 

In the above status tables:

 

HAZ = Hazard flag generated in the AE box indicating that two PHA events have occurred within the resolving time of the energy electronics and that therefore the energy signal may be corrupted by the previous event. Events with the HAZ bit set should be used with care.

 

LA = The two-bit encoding of which large SSD was selected for this event:
 
LA = 0 D5 or none
LA = 1 D6
LA = 2 D7 
LA = 3 Not defined
 

SA = The two-bit encoding of which small SSD was selected for this event:
 
SA = 0 D1 or none
SA = 1 D2
SA = 2 D3 
SA = 3 D4
 

D1-D7 = Individual discriminator bits showing which SSDs had signals above threshold for this event.

Box Number = Shows which matrix rate this event was accumulated into. See Ref 1 for more details.

CO = Cal mode / Normal mode bit, 1 = Cal Mode

ES = Identifies which energy system was used for this event. 0 = large SSDs, 1 = small SSDs

TOFn = Identifies which TOF system fired for this event. 1 = valid stop present

 

When the instrument is in CALIBRATE mode, status bit definitions shift somewhat. New status bits include:

CE = 12-bit number indicating the calibrator energy step associated with the event

SSD ID = 3-bit identification of which SSD is being calibrated

CAL STEP = 4-bit calibrator tof step which produced this event

CM = Calibrator mode. 1 = short.

(Note that the CO bit always stays in the same place so we can identify which events are calibrate events and which are not.)

 

 

4.4 SINGLE SPIN MATRIX RATES

 

Single-spin matrix rates are a group of 34 sectored rates read out each spin for best time resolution (12 secs). In the science record they appear as a block of 80 records of 34 rates each, each record representing a single sector of a single spin. The structure of the data block is shown in Table 4.4-1 and the detailed structure of a single matrix rate record is shown in Table 4.4-2.

 

Table 4.4-1 Single Spin Matrix Rate Data Block (Rec ID = 3)
 
Record Bytes Name Comment
1 36 Spin 1, Sect 0 Rates spin, sect, 34 rates, see below
2 36 Spin 1, Sect 1 Rates spin, sect, 34 rates, see below
…
8 36 Spin 1, Sect 7 Rates spin, sect, 34 rates, see below
9 36 Spin 2, Sect 0 Rates spin, sect, 34 rates, see below
…
80 36 Spin 10, Sect 7 Rates spin, sect, 34 rates, see below
 

 

Each line of the above table represents a single record, and each record contains 34 compressed rates and the spin and sector number structured as follows:

 

Table 4.4-2 Single Spin Matrix Spin Record Structure
 
Item Bits Name Comment Type
1 8  Spin number 1-10 byte
2 8  Sector Number 0-7 byte
3 8  Small SSD Background Box # 64 byte
4 8  H S1 65 byte
5 8  H S2 66 byte
6 8  H S3 67 byte
7 8  H S4 68 byte
8 8  H S5 69 byte
9 8  3He S1 70 byte
10 8  3He S2 71 byte
11 8  3He S3 72 byte
12 8  3He S4 73 byte
13 8  3He S5 74 byte
14 8  4He S1 75 byte
15 8  4He S2 76 byte
16 8  4He S3 77 byte
17 8  4He S4 78 byte
18 8  Large SSD Background 0 byte
19 8  3He L1 1 byte
20 8  3He L2 2 byte
21 8  3He L3 3 byte
22 8  3He L4 4 byte
23 8  3He L5 5 byte
24 8  3He L6 6 byte
25 8  4He L1 7 byte
26 8  4He L2 8 byte
27 8  4He L3 9 byte
28 8  4He L4 10 byte
29 8  4He L5 11 byte
30 8  4He L6 12 byte
31 8  4He L7 13 byte
32 8  4He L8 14 byte
33 8  4He L9 15 byte
34 8  4He L10 16 byte
35 8  4He L11 17 byte
36 8  4He L12 18 byte
 

Each of the 34 rates making up a single-spin record was stored in the DPU as a 16-bit number and was compressed from 16 to 8 bits before transmission to the S/C. It can be decompressed as follows:

 

Compressed rate is of the form: eeeemmmm

If eeee = 0, value = mmmm

Else value = (16+mmmm)* 2^(eeee-1)

 

The Box # in the above table refers to the DPU code for the matrix rate in question.

 

4.5 SPIN-PAIR MATRIX RATES

 

Spin-pair matrix rates are a group of 42 sectored rates accumulated in the DPU and read out every other spin to save bit rate at the expense of some loss in time resolution (24 seconds). In the science record they appear as a block of 40 records of 42 rates each, each record representing a single sector of a single spin pair. The structure of the data block is shown in Table 4.5-1 and the detailed structure of a single matrix rate record is shown in Table 4.5-2.

 

Like the single-spin matrix rates, the spin-pair rates are compressed. Each of the 42 rates making up a single-spin record was accumulated in the DPU as a 16-bit number and was compressed from 16 to 8 bits before transmission to the S/C. It can be decompressed as follows:

 

Compressed rate is of the form: eeeemmmm

If eeee = 0, value = mmmm

Else value = (16+mmmm)* 2^(eeee-1)

 

Table 4.5-1 Spin-Pair Matrix Rate Data Block (Rec ID = 4)
 
Record
Bytes
Name
Comment
1
44
 Spin 1\2, Sect 0 Rates spin, sect, 42 rates, see below
2
44
 Spin 1\2, Sect 1 Rates spin, sect, 42 rates, see below
…
8
44
 Spin 1\2, Sect 7 Rates spin, sect, 42 rates, see below
9
44
 Spin 3\4, Sect 0 Rates spin, sect, 42 rates, see below
…
40
44
 Spin 9\10, Sect 7 Rates spin, sect, 42 rates, see below
 

As with the single-spin rates above, each line of the above table represents a single record, and each record contains 42 compressed rates and the spin and sector number structured as in Tables 4-5-2 below. A DPU table upload on Feb 17-18 1998 added rate O L7 and bumped the following rates ahead one step. The before and after assignments are given in the ...a and ...b versions of Tables 4.5-2

 

 

Table 4.5-2a Spin-Pair Matrix Rate Record Structure: Launch – Feb 17 1998
 
Item # Bits Name Comment Type
1 8  Spin number 1-10 byte
2 8  Sector Number 0-7 byte
3 8  C S1 Box # 79  byte
4 8  C S2 80  byte
5 8  O S1 81  byte
6 8  O S2 82  byte
7 8  Ne-S S1 83  byte
8 8  Ne-S S2 84  byte
9 8  Fe S1 85  byte
10 8  Fe S2 86  byte
11 8  C L1 19  byte
12 8  C L2 20  byte
13 8  C L3 21  byte
14 8  C L4 22  byte
15 8  C L5 23  byte
16 8  C L6 24  byte
17 8  C L7 25  byte
18 8  C L8 26  byte
19 8  O L1 27  byte
20 8  O L2 28  byte
21 8  O L3 29  byte
22 8  O L4 30  byte
23 8  O L5 31  byte
24 8  O L6 32  byte
25 8  Ne-S L1 33  byte
26 8  Ne-S L2 34  byte
27 8  Ne-S L3 35  byte
28 8  Ne-S L4 36  byte
29 8  Ne-S L5 37  byte
30 8  Ne-S L6 38  byte
31 8  Ne-S L7 39  byte
32 8  Fe L1 40  byte
33 8  Fe L2 41  byte
34 8  Fe L3 42  byte
35 8  Fe L4 43  byte
36 8  Fe L5 44  byte
37 8  Fe L6 45  byte
38 8  Fe L7 46  byte
39 8  Fe L8 47  byte
40 8  Fe L9 48  byte
41 8  Unassigned reads out as 0 byte
42 8  Unassigned reads out as 0 byte
43 8  Unassigned reads out as 0 byte
44 8  Unassigned reads out as 0 byte

 

 

 

Table 4.5-2b Spin-Pair Matrix Rate Record Structure: Feb 18 1998 - present
 
Item # Bits Name Comment Type
1 8  Spin number 1-10 byte
2 8  Sector Number 0-7 byte
3 8  C S1 Box # 79  byte
4 8  C S2 80  byte
5 8  O S1 81  byte
6 8  O S2 82  byte
7 8  Ne-S S1 83  byte
8 8  Ne-S S2 84  byte
9 8  Fe S1 85  byte
10 8  Fe S2 86  byte
11 8  C L1 19  byte
12 8  C L2 20  byte
13 8  C L3 21  byte
14 8  C L4 22  byte
15 8  C L5 23  byte
16 8  C L6 24  byte
17 8  C L7 25  byte
18 8  C L8 26  byte
19 8  O L1 27  byte
20 8  O L2 28  byte
21 8  O L3 29  byte
22 8  O L4 30  byte
23 8  O L5 31  byte
24 8  O L6 32  byte
25 8  O L7 33  byte
26 8  Ne-S L1 34  byte
27 8  Ne-S L2 35  byte
28 8  Ne-S L3 36  byte
29 8  Ne-S L4 37  byte
30 8  Ne-S L5 38  byte
31 8  Ne-S L6 39  byte
32 8  Ne-S L7 40  byte
33 8  Fe L1 41  byte
34 8  Fe L2 42  byte
35 8  Fe L3 43  byte
36 8  Fe L4 44  byte
37 8  Fe L5 45  byte
38 8  Fe L6 46  byte
39 8  Fe L7 47  byte
40 8  Fe L8 48  byte
41 8  Fe L9 49 byte
42 8  Unassigned reads out as 0 byte
43 8  Unassigned reads out as 0 byte
44 8  Unassigned reads out as 0 byte
 

 

 

4.6 DISCRIMINATOR RATES

 

Discriminator rates are a group of 16 sectored rates accumulated in the AE Box and the DPU as 24-bit numbers and compressed to 16 bits for readout every other spin . In the science record they appear as a block of 40 records of 16 rates, each record representing a single sector of a single spin pair. The structure of the data block is shown in Table 4.6-1 and the detailed structure of a single discriminator rate record is shown in Table 4.6-2.

 

Decompression is as follows:

 
 
The compressed rate is of the form eeeemmmmmmmmmmmm 

 
For: eeee=0 

eeee <>0

 value = mmmmmmmmmmmm
value = (4096+mmmmmmmmmmmm)*2^(eeee-1)
 

 

 

Table 4.6-1 Discriminator Rate Data Block (Rec ID = 5)
 
Record
 Bytes
Name
Comment
1
34
 Spin 1\2, Sect 0 Rates spin, sect, 16 rates, see below
2
34
 Spin 1\2, Sect 1 Rates spin, sect, 16 rates, see below
…
8
34
 Spin 1\2, Sect 7 Rates spin, sect, 16 rates, see below
9
34
 Spin 3\4, Sect 0 Rates spin, sect, 16 rates, see below
…
40
34
 Spin 9\10, Sect 7 Rates spin, sect, 16 rates, see below
 

 

Table 4.6-2 Discriminator Rate Record Format
 
Item #
Bits
Name
Comment
Type
1
8 
 Spin number
1-10
byte
2
8 
 Sector Number
0-7
byte
3
16 
 D1 Singles
Rundown 1
int*2
4
16 
 D2 Singles
Rundown 2
int*2
5
16 
 D3 Singles
Rundown 3
int*2
6
16 
 D4 Singles
Rundown 4
int*2
7
16 
 D5 Singles
Rundown 5
int*2
8
16 
 D6 Singles
Rundown 6
int*2
9
16 
 D7 Singles
Rundown 7
int*2
10
16 
 START1 Singles
START1
int*2
11
16 
 START2 Singles
START2
int*2
12
16 
 STOP Singles
STOP
int*2
13
16 
 VS1
START1 * STOP
int*2
14
16 
 VS2
START2 * STOP
int*2
15
16 
 Event
VS * E * /Busy
int*2
16
16 
 START1 Wedge
S1(W+S+Z)
int*2
17
16 
 START2 Wedge
S2(W+S+Z)
int*2
18
16 
 STOP Wedge
STOP(W+S+Z)
int*2
 

VS1 = valid stop 1 = Start1 signal followed within 350nS by a Stop signal

VS2 = valid stop 2 = Start2 signal followed within 350nS by a Stop signal

VS = valid stop = VS1 and/or VS2 as selected by Telescope command

S* Wedge = S* wedge was active, any combination of W or S or Z

 

 

 

4.7 STATUS & INSTRUMENT HOUSEKEEPING

 

Status and Instrument housekeeping data are a diverse set of items presenting information about the state and condition of the telescope and iris, AE box and DPU, hardware and software. They are collected by the DPU and formatted into 14 bytes at the beginning of each major frame and into 128 bytes at the end of the 8th major frame in a science record (see Fig 2.2-1 above). In Level_1 data these are gathered into two groups: the 8 major frames of 14 bytes form the Status Block and the 128 bytes at the end form the Status Trailer. This format is carried over into the UDF structure and so the Status and Instrument Housekeeping are read out as 2 records: one Status Block and one Status Trailer. This is shown in Table 4.7-1.

Table 4.7-1 Status Data Block (Record ID = 6)
 
Record # Bytes Name Comment
1 112 Status Block 8 major frames, 14 bytes each
2 128 Status Trailer
 

The internal structure of the Status Block and Status Trailer are shown in Tables 4.7-2 and 4.7-3. More data on the definition of the various data items can be found in the reference in 1.0 above. One further item to note is that the instrument analog housekeeping, usually given a data block of its own, is here located in the middle of the Status Trailer (item 9). This housekeeping data is a block of 48 bytes representing the Average, Minimum and Maximum value of 16 analog HK channels sampled 1/sec over the science record. The data is in binary form as measured by an 8-bit ADC in the DPU. The format for this data is given in Table 4.7-4 below. Data is given in raw binary form. For conversion to engineering units, see TBD.

 

Table 4.7-2 Status Block Record Format
 
Item # Bits Name Comment Type Index in 

STATUS_BLOCK  

Array
1
16 
 Sync Major Frame 0
int*2
1 
2
16 
 Software ID
int*2
1 
3
16 
 MinFrCnt
int*2
2 
4
16 
 CmdAccCnt
int*2
2 
5
16 
 CmdRejCnt
int*2
3 
6
32 
 CmdEcho
int*4
3,4
7
32 
 RejCmdEcho Major Frame 1
int*4
4,5
8
16 
 CmdSide1IntrCnt
int*2
5 
9
16 
 CmdSide2IntrCnt
int*2
6 
10
16 
 CodePagNum
int*2
6 
11
16 
 SunSectrID
int*2
7 
12
16 
 SpinCntReg
int*2
7 
13
16 
 WatchdogCnt Major Frame 2
int*2
8 
14
16 
 RamPag1TestRslts
int*2
8 
15
16 
 RamPag2TestRslts
int*2
9 
16
16 
 EEPROMCksum
int*2
9 
17
16 
 TimerIntrCnt
int*2
10 
18
16 
 CurTLMSide
int*2
10 
19
16 
 DefTLMSide
int*2
11 
20
16 
 MemPekVal Major Frame 3
int*2
11 
21
16 
 MemPekPagNum
int*2
12 
22
16 
 MemPekAddr
int*2
12 
23
16 
 MemPokVal
int*2
13 
24
16 
 MemPokPagNum
int*2
13 
25
16 
 MemPokAddr
int*2
14 
26
16 
 MemDmpPagNum
int*2
14 
27
16 
 MemDmpAddrPntr Major Frame 4
int*2
15 
28
16 
 OutputPort0PokVal
int*2
15 
29
16 
 OutputPort1PokVal
int*2
16 
30
16 
 OutputPort2PokVal
int*2
16 
31
16 
 OutputPort6PokVal
int*2
17 
32
16 
 InputPort0Val
int*2
17 
33
16 
 InputPort1Val
int*2
18 
34
16 
 InputPort2Val Major Frame 5
int*2
18 
35
16 
 InputPort6Val
int*2
19 
36
16 
 EEPROMPag3Stat
int*2
19 
37
16 
 EEPROMPag67Stat
int*2
20 
38
16 
 CtrlWord2CmdStat
int*2
20 
39
16 
 MemLdSiz
int*2
21 
40
16 
 MemLdPag
int*2
21 
41
16 
 MemLdAddr Major Frame 6
int*2
22 
42
16 
 MemLdCksum
int*2
22 
43
16 
 MemLdComCksum
int*2
23 
44
16 
 MemLdCksumErrCnt
int*2
23 
45
16 
 AECmdErrCnt
int*2
24 
46
16 
 AECmdIntrCnt
int*2
24 
47
16 
 MajFrCntx8
int*2
25 
48
16 
 Spn1SpnCnt Major Frame 7
int*2
25 
49
16 
 Spn2SpnCnt
int*2
26 
50
16 
 Spn3SpnCnt
int*2
26 
51
16 
 Spn4SpnCnt
int*2
27 
52
16 
 Spn5SpnCnt
int*2
27 
53
16 
 Spn6SpnCnt
int*2
28 
54
16 
 Spn7SpnCnt
int*2
28 
 

 

Table 4.7-3 Status Trailer Record Format
 
Item # Bits Name Comment Type Index in STATUS_TRAILER Array
1 16  Spn8SpnCnt; Byte: 1-2 int*2 1 
2 16  Spn9SpnCnt; Byte: 3-4 int*2 1 
3 16  Spn10SpnCnt; Byte: 5-6 int*2 2 
4 16  CumSpnCnt; Byte: 7-8 int*2 2 
5 16  EvntCnt; Byte: 9-10 int*2 3 
6 16  Spn1MinFrCnt; Byte: 11-12 int*2 3 
7 8  HVAutFlg; Byte: 13 byte 4 
8 8  HVActFlg; Byte: 14 byte 4 
9 48*8 HK_ADC(48) Byte: 15-62  

see detail below

 Byte 

Array

 4-16
10 8  PHAFrzFlg; Byte: 63  

0=disable, 1 = enable

 Byte 16 
11 8  SSDEnaFlg; Byte: 64 Byte 16 
12 8  AEAutoResetEnaFlg; Byte: 65 byte 17 
13 8  CalModFlg; Byte: 66 byte 17 
14 8  TOFFlg; Byte: 67  

22=tof1, 24 = tof2

 byte 17 
15 8  AETlltlBits; Byte: 68 byte 17 
16 16  MotrAutFlg; Byte: 69-70 int*2 18 
17 8  MotrPwrFlg; Byte: 71  

nonzero = on

 byte 18 
18 8  MotrFid; Byte: 72 byte 18 
19 16  MotrPostn; Byte: 73-74 int*2 19 
20 16  Rt1MinSectr; Byte: 75-76 int*2 19 
21 16  Rt1MinSpn; Byte: 77-78 int*2 20 
22 16  Rt1HiSecErrLim; Byte: 79-80 int*2 20 
23 16  Rt1LoSecErrLim; Byte: 81-82 int*2 21 
24 16  Rt1HiSpnErrLim; Byte: 83-84 int*2 21 
25 16  Rt1LoSpnErrLim; Byte: 85-86 int*2 22 
26 16  Rt1Indx; Byte: 87-88 int*2 22 
27 16  Rt2MinSectr; Byte: 89-90 int*2 23 
28 16  Rt2MinSpn; Byte: 91-92 int*2 23 
29 16  Rt2HiSecErrLim; Byte: 93-94 int*2 24 
30 16  Rt2LoSecErrLim; Byte: 95-96 int*2 24 
31 16  Rt2HiSpnErrLim; Byte: 97-98 int*2 25 
32 16  Rt2LoSpnErrLim; Byte: 99-100 int*2 25 
33 16  Rt2Indx; Byte: 101-102 int*2 26 
34 16  MtrErrFlg; Byte: 103-104 int*2 26 
35 8  MtrMotnFlg; Byte: 105 byte 27 
36 8  EvntRdoutFmt; Byte: 106 byte 27 
37 8  MUXSelMd; Byte: 107 byte 27 
38 8  VS1Enab; Byte: 108 byte 27 
39 8  VS2Enab; Byte: 109 byte 28 
40 8  VS1VS2Enab; Byte: 110 byte 28 
41 16  PHARnkSpn1Sec1; Byte: 111-112 int*2 28 
42 16  PHARnkSpn1Sec2; Byte: 113-114 int*2 29 
43 16  PHARnkSpn1Sec3; Byte: 115-116 int*2 29 
44 16  PHARnkSpn1Sec4; Byte: 117-118 int*2 30 
45 16  PHARnkSpn1Sec5; Byte: 119-120 int*2 30 
46 16  PHARnkSpn1Sec6; Byte: 121-122 int*2 31 
47 16  PHARnkSpn1Sec7; Byte: 123-124 int*2 31 
48 16  PHARnkSpn1Sec8; Byte: 125-126 int*2 32 
49 16  SciRecCksum; Byte: 127-128 int*2 32 
 

 

 

Table 4.7-4 ULEIS Housekeeping Detail
 
Item # Bits Name Alternate Set Type Trailer 

Index

 Byte of  

Longword
1 8  START1 Temp Avg -6v, Min byte 4  3 
2 8  START1 Temp, Min -6v, Max byte 4 
3 8  START1 Temp, Max -6v, Avg byte 5  1 
4 8  IFC Temp, Avg -5v, Min byte 2 
5 8  IFC Temp, Min -5v, Max byte 3 
6 8  IFC Temp, Max -5v, Avg byte 4 
7 8  SSD Bias V, Avg +12v, Min byte 6  1 
8 8  SSD Bias V, Min +12v, Max byte 2 
9 8  SSD Bias V, Max +12v, Avg byte 3 
10 8  Foil Temp, Avg byte 4 
11 8  Foil Temp, Min byte 7  1 
12 8  Foil Temp, Max byte 2 
13 8  SSD Bias I, Avg byte 3 
14 8  SSD Bias I, Min byte 4 
15 8  SSD Bias I, Max byte 8  1 
16 8  HV1 Ctrl, Avg byte 2 
17 8  HV1 Ctrl, Min byte 3 
18 8  HV1 Ctrl, Max byte 4 
19 8  HV2 Ctrl, Avg byte 9  1 
20 8  HV2 Ctrl, Min byte 2 
21 8  HV2 Ctrl, Max byte 3 
22 8  HV3 Ctrl, Avg byte 4 
23 8  HV3 Ctrl, Min byte 10  1 
24 8  HV3 Ctrl, Max byte 2 
25 8  +6v, Avg byte 3 
26 8  +6v, Min byte 4 
27 8  +6v, Max byte 11  1 
28 8  +5V, Avg byte 2 
29 8  +5V, Min byte 3 
30 8  +5V, Max byte 4 
31 8  SSD Temp, Avg byte 12  1 
32 8  SSD Temp, Min byte 2 
33 8  SSD Temp, Max byte 3 
34 8  Thresh Mon, Avg byte 4 
35 8  Thresh Mon, Min byte 13  1 
36 8  Thresh Mon, Max byte 2 
37 8  TOF Temp, Avg byte 3 
38 8  TOF Temp, Min byte 4 
39 8  TOF Temp, Max byte 14  1 
40 8  HV1 Mon, Avg byte 2 
41 8  HV1 Mon, Min byte 3 
42 8  HV1 Mon, Max byte 4 
43 8  HV2 Mon, Avg byte 15  1 
44 8  HV2 Mon, Min byte 2 
45 8  HV2 Mon, Max byte 3 
46 8  HV3 Mon, Avg byte 4 
47 8  HV3 Mon, Min byte 16  1 
48 8  HV3 Mon, Max byte 2 
 

4.8 S/C HOUSEKEEPING

 

Spacecraft housekeeping is read out as a single 682-byte record. Details of the record format are given in Table 4.8-1 below.

Data is in raw, packed format. Items 1-4 indicate which of the 128 minor frames in the 8-major-frame-long science data record contain Dump or Status mode data. There is one byte per minor frame for each mode. Since no minor frames are expected to contain Dump or Status data for the majority of the mission, two total bytes are also included for easy check. A recommended quality check of the data is to verify that items 2 and 4 are zero. If not, the SDR should be discarded.

Items 5-13 are byte arrays, each byte representing the value of one item during one major frame. Items 14 and 15 are byte arrays each byte representing the value of one item during one minor frame (16 mf/MF, 8 MF/Science Record). Items 16 and 17 give the time for each sun pulse and since there can be up to 2 sun pulses per major frame, there are two slots in each major frame for the data. Item 16 gives the least significant 16 bits of the SC Time for each sunpulse and item 17 gives data to correct the S/C time to sub-second accuracy. None of this is used by UMD at this time. Some more data on decoding items 13 and 17 are given in the notes below. In addition the C&DH specification reports, cryptically:

 
 
/* For the time tag in Science minor frame 0: for a minor */
/* frame ID of 0, the sun pulse would have occurred in the */
/* current major frame. For a minor frame ID of 1 to 15, */
/* the sun pulse would have occurred in the previous major */
/* frame */
/* For the time tag in Science minor frame 8: for a minor */
/* frame ID of 0-8, the sun pulse would have occurred in the */
/* current major frame. For a minor frame ID of 9 to 15, */
/* the sun pulse would have occurred in the previous major */
/* frame */
 

Table 4.8-1 S/C HSKP Record Format
 
Item #
Bits
Name
Comment
Type
1
128*8
 dump_flag(128) For each min fr, 1 = contains Dump data
Byte array
2
8 
 dump_flag_total number on non-zero dump flags
Byte
3
128*8
 stat_tlm_flag(128) For each minor fr, 1 = contains Status TLM
Byte array
4
8 
 stat_tlm_flg_total number of non-zero status flags
Byte
5
8*8
 DeckTemp(8) Deck temperature near ULEIS, 1/Maj frame
Byte array
6
8*8
 LVPS_V(8) (DPU 5vsupply?)
Byte array
7
8*8
 total_current(8) Total ULEIS current
Byte array
8
8*8
 AE_lvps_current(8) AE box lvps current
Byte array
9
8*8
 heater_current(8)
Byte array
10
8*8
 Telescope_Temp(8) s/c powered thermistor, at system connector
Byte array
11
8*8
 AE_Temp(8) s/c powered thermistor, at system connector
Byte array
12
8*8
 DPU_Temp(8)
Byte array
13
8*8
 ULEIS_Pwr_Sw(8) see note below
Byte array
14
128*8
 PhaseAng(128) sunpls phase angle for each minor frame
Byte array
15
128*8
 SunSenID(128) bits 7-2=0, bit1=sunsenstop, bit0=...side
Byte array
16
8*2*16
 SunPlsLatch(8,2) sctime of sunpls mf 0 & 8 for each MajFr
int*2 array
17
8*2*32
 SunPlsDat(8,2) Time of sun pulse
int*4 array
 

NOTE: Additional information for a few items is available:

 

Item 13: ULEIS Power Switching – The ULEIS_PWR_SW byte indicates which elements of ULEIS are switched on in the S/C, one bit per element, 1=ON, 0=OFF
 
Bit # Element Bit Position in S/C Structure
7 (MSB) Internal Heaters 20
6 Interface Heater 21
5 Main System Power 24
4 Pyro A Arm (ICI-1SE192F) 60
3 Pyro B Arm 63
2 0  
1 0  
0 0  
 

Item 17: SUN_PULSE_DATA
 
 
Bit #31-24 Unused (=0)
23-20 Minor frame number (0-15)
19-10 Sub-second count (684.75 counts = 1 sec)
9-8 ID (00=err,01=top,10=side,11=neither)
7-0 Y angle measurement (Grey Code)
 

 

5.0 BROWSE DATA

 

Section 4 above covers all the data that are included in the Level_1 data files. However, there also exists selected browse data from the ACE instruments averaged over 5 minute and 1 hour periods that we incorporate into the finished ULEIS Data Files. This data is available in a series of files named on the pattern of ACE_BROWSE_1998-187_TO_1998-237.HDF or

ACE_BROWSE_1998-238_TO_PRESENT.HDF and available by FTP from directory pub/ace/browse at MUSSEL.SRL.CALTECH.EDU. It is interleaved with the level 1 data by the program ADD_BROWSE.FOR. In the case of the 5-minute averaged data, the averages are placed in the first science record whose central 144 seconds includes the center point of the browse average period. In the case of the 1-hour averages, the data are placed in the science record that contains the 5-minute average beginning on the half-hour.

5.1 FIVE-MINUTE AVERAGE BROWSE DATA

 

Browse data is available in 5-minute averaged format for:

Magnetometer

SEPICA

EPAM

ULEIS

SWEPAM

Browse data for each of these instruments is incorporated in the UDF files. Details of the formats are given below.

 

.

5.1.1 MAGNETOMETER 5-MINUTE AVERAGE BROWSE

 

The magnetometer 5-minute average data is read out as a single record of 17 bytes organized as in table 5.1.1-1 below.

 

Table 5.1.1-1 Magnetometer 5-Min Browse Record Format (Rec ID=8)
 
Item# Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 5-min bin
Int*4
2
32 
 B_gse_theta_MAG AVG Magnetic field, GSE coordinate, latitude
Real*4
3
32 
 B_gse_phi_MAG AVG Magnetic field, GSE coordinate, longitude
Real*4
4
32 
 B_magnitude_MAG AVG Magnetic field, magnitude 
Real*4
5
16 
 B_weight  number of vectors used in this average
Int*2
 
 
Note: For future reference, the full 5-min browse parameters include the following, not all of which is merged with the UDF:
 
 
float32 B_rtn_r_MAG; /* AVG Magnetic field, RTN coordinate, R component */
float32 B_rtn_t_MAG; /* AVG Magnetic field, RTN coordinate, T component */
float32 B_rtn_n_MAG; /* AVG Magnetic field, RTN coordinate, N component */
float32 B_rtn_theta_MAG; /* AVG Magnetic field, RTN coordinate, latitude*/
float32 B_rtn_phi_MAG; /* AVG Magnetic field, RTN coordinate, longitude */
float32 B_gse_x_MAG; /* AVG Magnetic field, GSE coordinate, R component */
float32 B_gse_y_MAG; /* AVG Magnetic field, GSE coordinate, T component */
float32 B_gse_z_MAG; /* AVG Magnetic field, GSE coordinate, N component */
float32 B_gse_theta_MAG; /* AVG Magnetic field, GSE coordinate, latitude*/
float32 B_gse_phi_MAG; /* AVG Magnetic field, GSE coordinate, longitude */
float32 B_magnitude_MAG; /* AVG Magnetic field, magnitude */
uint32 B_weight; /* number of vectors used in this average */ 

Note: From v2-6 data, the B_weight in the HDF Browse file is uint32 (was uint16). This is converted to integer*2 in "process_udf" so as not to change the UDF format. 

 
5.1.2 SEPICA 5-MINUTE AVERAGE BROWSE

 

The SEPICA 5-minute average data is read out as a single record of 40 bytes organized as in table 5.1.2-1 below. This record and its record ID will appear only for those 5-minute browse periods in which the SEPICA livetime (item 10 below) is greater than 0.

 

Table 5.1.2-1 SEPICA 5-Min Browse Record Format (Rec ID=9)
 
Item # Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 5-min bin
int*4
2
32 
 H_lo_SEP H rate, 0.1-0.8 Mev/n
real*4
3
32 
 H_hi_SEP H rate, 0.8-6.0 Mev/n
real*4
4
32 
 He_lo_SEP He rate, 0.025-0.75 Mev/n
real*4
5
32 
 He_hi_SEP He rate, 0.75-6.0 Mev/n
real*4
6
32 
 C_SEP C rate, 1.5-10.7 Mev/n
real*4
7
32 
 O_SEP O rate, 1.25-12.6 Mev/n
real*4
8
32 
 MgSi_SEP MgSi rate, 0.77-11.54
real*4
9
32 
 Fe_SEP Fe rate, 0.36-5.36 Mev/n
real*4
10
32 
 SEP_livetime SEPICA livetime, if 0 ignore SEP data 
real*4
 

 

 

5.1.3 EPAM 5-MINUTE AVERAGE BROWSE

 

The EPAM 5-minute average data is read out as a single record of 36 bytes organized as in table 5.1.3-1 below. This record and its record ID will appear only for those 5-minute browse periods in which the EPAM live time (item 9 below) is greater than 0.

 

Table 5.1.3-1 EPAM 5-Min Browse Record Format (Rec ID=10)
 
Item # Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 5-min bin
int*4
2
32 
 H_EPAM H rate, 0.48-0.97 Mev/n
real*4
3
32 
 Ion_vlo_EPAM Ion rate, 47-65 keV 
real*4
4
32 
 Ion_lo_EPAM Ion rate, 112-187 keV
real*4
5
32 
 Ion_mid_EPAM Ion rate, 310-580 keV
real*4
6
32 
 Ion_hi_EPAM Ion rate, 1060-1910 KeV
real*4
7
32 
 e_lo_EPAM electron rate, 38-53 keV
real*4
8
32 
 e_hi_EPAM electron rate, 175-315 keV
real*4
9
32 
 EPAM_livetime EPAM livetime. if 0 ingnore EPM data
real*4
 

 

 

5.1.4 ULEIS 5-MINUTE AVERAGE BROWSE

 

The ULEIS 5-minute average data is read out as a single record of 44 bytes organized as in table 5.1.4-1 below. This record and its record ID will appear only for those 5-minute browse periods in which the ULEIS livetime (item 11 below) is greater than 0.

 

Table 5.1.4-1 ULEIS 5-Min Browse Record Format (Rec ID=11)
 
Item # Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 5-min bin
int*4
2
32 
 H_lo_ULS H rate, 0.16-0.32 Mev/n
real*4
3
32 
 H_hi_ULS H rate, 0.64-1.28 Mev/n
real*4
4
32 
 He3_ULS He3 rate, 0.64-1.28 Mev/n
real*4
5
32 
 He4_lo_ULS He4 rate, 0.08-0.113 Mev/n
real*4
6
32 
 He4_hi_ULS He4 rate, 0.64-0.905 Mev/n
real*4
7
32 
 O_lo_ULS O rate, 0.09-0.160 Mev/n
real*4
8
32 
 O_hi_ULS O rate, 0.64-1.28 Mev/n
real*4
9
32 
 Fe_lo_ULS Fe rate, 0.08-0.160 Mev/n
real*4
10
32 
 Fe_hi_ULS Fe rate, 0.64-0.905 Mev/n
real*4
11
32 
 ULS_livetime ULEIS livetime. If 0 ingnore ULS data
real*4
 

 

 

5.1.5 SWEPAM 5-MINUTE AVERAGE BROWSE

 

The SWEPAM 5-minute average data is read out as a single record of 24 bytes organized as in table 5.1.5-1 below. This record and its record ID will appear only for those 5-minute browse periods in which the number of values in average (item 6 below) is less than 2.

 

Table 5.1.5-1 SWEPAM 5-Min Browse Record Format (Rec ID=12)
 
Item # Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 5-min bin
int*4
2
32 
 H_den_SWP proton number density, cm^-3
real*4
3
32 
 He_ratio_SWP nHe++/nH+
real*4
4
32 
 SW_spd_SWP Solar Wind bulk (H) speed
real*4
5
32 
 Trr_SWP (1,1) comp. of temp tensor along radial direction
real*4
6
32 
 SWP_weight Number of values in average
real*4
 

 

 

5.2 ONE-HOUR AVERAGE BROWSE

 

Browse data averaged over an hour is available for the following instruments:

Magnetometer

SEPICA

EPAM

ULEIS

SWEPAM

CRIS

SIS

There is a rumor that browse data for SWICS and SWIMS will become available at some time in the future, but this is still in the works.

 

Of the above, only the CRIS and SIS 1-hour averaged data are incorporated into the UDFs. The other instruments are included as 5-minute averages (see above).

 

5.2.1 CRIS 1-HOUR AVERAGE BROWSE

 

The CRIS 1-hour average data is read out as a single record of 56 bytes organized as in table 5.2.1-1 below.

 

Table 5.2.1-1 CRIS 1-Hr Browse Record Format (Rec ID=13)
 
Item # Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 1-hr bin
int*4
2
32 
 He_lo_CRIS not implemented
real*4
3
32 
 He_mid_CRIS not implemented
real*4
4
32 
 He_hi_CRIS not implemented
real*4
5
32 
 CNO_lo_CRIS not implemented
real*4
6
32 
 CNO_mid_CRIS not implemented
real*4
7
32 
 CNO_hi_CRIS not implemented
real*4
8
32 
 CNO_Sum_CRIS not implemented
real*4
9
32 
 HiZ_lo_CRIS not implemented
real*4
10
32 
 HiZ_mid_CRIS not implemented
real*4
11
32 
 HiZ_hi_CRIS not implemented
real*4
12
32 
 HiZ_Sum_CRIS Z>=10 nuclei with 100-400 Mev/nuc
real*4
13
32 
 Pen_CRIS not implemented, penetrating nuclei
real*4
14
32 
 HiZ_Pen_CRIS Flux of Z>=10, E>300Mev/n nuclei
real*4
 

 

 

5.2.2 SIS 1-HOUR AVERAGE BROWSE

 

The SIS 5-minute average data is read out as a single record of 20 bytes organized as in table 5.2.2-1 below.

 

Table 5.2.2-1 SIS 5-Min Browse Record Format (Rec ID=14)
 
Item # Bits Name Comment Type
1
32 
 bin_time ACE_epoch time of start of 1-hr bin
int*4
2
32 
 He_SIS Not implemented. He rate , 5.5 Mev/n
real*4
3
32 
 CNO_lo_SIS CNO rate , 7-10 Mev/n
real*4
4
32 
 CNO_hi_SIS CNO rate , 10-15 Mev/n
real*4
5
32 
 HiZ_SIS Flux of Z>=10, 9-21Mev/n nuclei
real*4
 

 
 
float32 H_lo_ULS; /* H rate, 0.16-0.32 Mev/n from ULEIS */
float32 H_hi_ULS; /* H rate, 0.64-1.28 Mev/n from ULEIS */
float32 He3_ULS; /* He3 rate, 0.64-1.28 Mev/n from ULEIS */
float32 He4_lo_ULS; /* He4 rate, 0.08-0.113 Mev/n from ULEIS */
float32 He4_hi_ULS; /* He4 rate, 0.64-0.905 Mev/n from ULEIS */
float32 O_lo_ULS; /* O rate, 0.09-0.160 Mev/n from ULEIS */
float32 O_hi_ULS; /* O rate, 0.64-1.28 Mev/n from ULEIS */
float32 Fe_lo_ULS; /* Fe rate, 0.08-0.160 Mev/n from ULEIS */
float32 Fe_hi_ULS; /* Fe rate, 0.64-0.905 Mev/n from ULEIS */
float32 ULS_livetime; /* ULEIS livetime. if 0 ingnore ULS data */
/* Negative values are non-physical */
float32 H_den_SWP; /* proton number density, cm^-3, from SWEPAM */
float32 He_ratio_SWP; /* nHe++/nH+, from SWEPAM */
float32 SW_spd_SWP; /* Solar Wind bulk (H) speed from SWEPAM */
float32 Trr_SWP; /* (1,1) component of temp tensor along */
/* radial direction from SWEPAM */
float32 SWP_weight; /* Number of values in average */
/* NO 5min averages from CRIS or SIS */