| Version |
$Revision: 1.3 $ |
| Last Update |
$Date: 2001/11/08 14:46:10 $ |
| HRC CCB Status |
NA |
Number: HRC-L-005
Type: Limitation
Original Date: 1999 January 6
Subsystem: HRC
Subject: Telemetry Format Changes
Source: IF1-20 Section 3.6.2.5
CRL Statement:
Any commanded change in the telemetry format shall be preceded by a
serial digital command to the HRC specifying that the HRC will be
provided with:
- 24-kbps downlink for science data (Format 1 send HRC serial
digital command 2OBSVASL)
- 512-bps downlink for science data (Non-format 1 send HRC serial
digital command 2NXILASL)
These commands should occur within half a second prior to a commanded telemetry
format change.
CRL Rationale/Justification:
The HRC uses different signals to synchronize its serial digital data
to the spacecraft telemetry stream depending on its downlink
allocation. It must be commanded to change the synchronization pulse
it uses when the allocation changes if it is to provide valid serial
digital data.
CRL Impact:
If the appropriate serial digital command is not issued to the HRC
when the telemetry allocation for downlinked science data is changed,
incorrect serial digital data will be sent. This will result in an
inability to monitor the health and safety of the HRC and the possible
loss of science data.
Recommended Action:
Incorporate into the Systems and Operations Procedures, with ASC providing
the inputs.
$Log: hrc-l-005.html,v $
Revision 1.3 2001/11/08 14:46:10 juda
HTML "href" tag edits to convert to soft links
Revision 1.2 1999/01/13 16:52:33 juda
added references to telemetry format number and timimg of commands
Revision 1.1 1999/01/06 15:30:17 juda
Initial revision
Dr. Michael
Juda
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, Mail Stop 70
Cambridge, MA 02138, USA
Ph.: (617) 495-7062
Fax: (617) 495-7356
E-mail: mjuda@cfa.harvard.edu