Fundamental Technologies

Voyager LECP Pages

Cruise 7 (Cruise 5a)

2 April 1981

Dr. S. M. Krimigis
Johns Hopkins University
Applied Physics Laboratory
Johns Hopkins Road
Laurel, Maryland 20810

Dear Dr. Krimigis:

Attached is a rough draft of the proposed EDR format for Cruise 7 (CR-7) telemetry data. This attachment describes only the LECP subheader and science data block. The standard EDR header will be used. The CR-7 format is intended to closely follow that for CR-5 with modifications made to allow for the different timing and data cycling in CR-7.

Please have your cognizant personnel review this material by April 17. I will be contacting each group by telephone prior to that date to discuss any questions that may arise.

Please feel free to call me at FTS 792-7840.

Sincerely,

David Wagner

DW:pp
Encl.
cc:
T. Armstrong
R. Collins
E. Franzgrote
G. Gloeckler
E. Keath
L. Lanzerotti
A. Sacks
C. Stembridge
E. Stone
H. Woo

618-306, CR-7, Revision D, Change 3

10.3 Low Energy Charged Particle (LECP) Experiment

The LECP EDR science physical record consisting of 24 CR-7 MFs corresponds to a 19.2 minute measurement period which is equivalent to three LECP instrument data cycles.

The LECP CR-7 EDR physical record structure is shown in Figure 10.3-1 and the physical magnetic tape organization is shown in Figure 10.3-2

.

Figure 10.3-1, LECP Science Physical Tape Records

Standard Header
(60-Words)		 Subheader
(8-Words)		 Data Block
(384-Words)		 24 MF
19.2 MIN
452 Words

All Words 32-Bits

One physical record contains a standard EDR header followed by the LECP peculiar subheader and data block for 24 CR-7 telemetry frames.

One physical record contains 3 instrument cycles.

Figure 10.3.2 Physical Magnetic Tape Configuration for EDR Cruise 7.

Figure 10.3-3 defines the structure and the contents of the LECP CR-7 EDR science record subheader. Figure 10.3-4 defines the structure and contents of the LECP CR-7 EDR science data block. The standard CR-7 EDR header is specified in Appendix C.

Figure 10.3-3, LECP Science Subheader Format

EDR Word

Bits
31 15              0 31 15            0
1

LECP CMD 1
MF 1

LECP CMD 2
MF 14

LECP CMD 3
MF 22

Spare
2

Spare

Spare
3

Spare

Spare
5

Spare

Spare

Total block length is 8 (32-bit) EDR words (24 MF; 1 to 3 LECP CMD words).

MF 1 is in:

SCT 60 = 0,24,48 when MOD 216 is even;
SCT 60 = 12,36 when MOD 216 is odd.

Figure 10.3-4, LECP EDR Science Logical Record Format

MF EDR Word

Bits
31     16   15        0   31      16   15      0
1 1 P1 P2 P3 P4
1 3 P5 P6 P7 P8
1 5 P9 P10 P11 P12
1 7 P13 P14 P15 P16
1 9 R1 R2 R3 R4
1 11 R5 R6 R7 R8
1 13 R9 R10 R11 R12
1 15 R13 R14 R15 R16
2 17 P1 P2 P3 P4
: : : : : :
24 383 R13 R14 R15 R16

P = PHA Word
R = Rate/Status Word

Logical record length is 384 (32-bit) EDR words equivalent to 24 MF or 768 LECP 10-bit words.

MF 1 is in:

SCT 60 = 0,24,48 when MOD 216 = EVEN;
SCT 60 = 12,36 when MOD 216 = ODD.

Return to EDR main page.
Return to Voyager LECP Data Analysis Handbook Table of Contents.
Return to Fundamental Technologies Home Page.

Last modified 4/27/05, Tizby Hunt-Ward
tizby@ftecs.com