HELIX CTI-CRYOGENICS On-Board FastRegen Programming And Operation Instructions page 89

On-Board FastRegen Control Module Programming and Operation Instructions
P/N 8040406
There are three categories of error messages. Each category has two possi-
ble messages. The first is an error under normal conditions. The second is
an error message that also signals a recent power loss. If a power loss sig-
nal is received, this flag can be reset by using the S command .
1. The normal reply for an understandable and executable mes-
sage is A. If this inquiry is the first since a power failure, the
message is B.
2. If a command is sent that cannot be executed under any conditions,
the error message is E. If this inquiry is the first since a power fail-
ure, the message is F.
3. If a command is sent that cannot be executed except under certain
conditions, due to interlocks, the return message is G. If this inquiry
is the first since a power failure, the message is H.
NOTE: If using a Network Teminal or On-Board Central Control software,
the only reply you will see will be "A". This reply occurs because the error
messages will have been cleared by the Network Teminal or On-Board
Central Control software. If your system utilizes a Network Teminal or On-
Board Central Control software, you should use the lower case t command
as described in Table B-1 (within this appendix) and Appendix E if you
wish to have your system controller recognize a power failure signal which
is recorded in the pump.
Between the time that the host sends a command/ query and the slave
returns a response message, further characters sent from the host to the
slave are ignored. The slave will respond to any verified message packet it
receives within one second. A timeout period in excess of this within host
can be used to detect a failure and need to re-try. Once a response to a
message has been received by the host, new command/query messages
may be immediately sent out (at a rate that will be faster than the one-sec-
ond turnaround timeout). In this way the message traffic is self
synchronizing.
The following is an example of a typical exchange:
Host sends query to get back On-Board Module version information
Flag
ASCII [$]
Hex [24]
Data Field Checksum
[@] [1]
[40] [31]
-
C TI CRYOGENICS
HELIX TECHNOLOGY CORPORATION
Terminator
[CR]
[0D]
B-3