64
MANUAL P/N 316005 REV: B
PCS
Definition:
Display process control channel status.
Modifiers:
1 or 2 or 3 or 4 or 5 or 6 or B or none.
Response:
Depends on modifier:
Modifier = single digit (1 through 6); response = single ASCII digit, 0 if the corresponding
relay is inactive, 1 if active.
Modifier = B; response = a byte of data with bits 0 through 5 set/clear according to
whether the corresponding relay is
active/inactive. Bit 6 will always be set to
guarantee that the returned byte will not appear as a terminator byte.
Modifier absent; response will be a string of 6 ASCII 0's and 1's separated by commas
giving the status of all six channels.
Examples:
Assume that channels 1 through 3 are active, and 4 through 6 are inactive:
From computer: PCS 1 CRLF
From 316: 1CRLF
From computer: PCS B CRLF
From 316: GCRLF
The ASCII "G" corresponds to the bit pattern 01000111 and represents the status of the
PC channels in bits 0 through 5.
From computer: PCS CRLF
From 316: 1,1,1,0,0,0CRLF
Error Messages
If an error is found in the incoming message, one of the following messages will be returned in place of the
normal response, and if the SRQ mode is used, bit 5 in the serial poll response byte will be set.
OVERRUN ERROR - Returned if the incoming message overflows 316's buffer.
SYNTAX ERROR - Returned if the message fails to parse as a valid 316 command.
7.4 IEEE 488 Troubleshooting
If your interface fails to function, first verify the following:
1.
Check the switch settings
Be sure the controller knows the address of the 316 as set by the DIP switches. Be sure the system
controller does not reserve certain addresses for system devices, e.g., a printer. Be sure the 316 is
not in the talk-only mode unless desired for data logging. Be sure, if the SRQ mode is set, that your
controller performs a serial poll in response to the SRQ from the 316 VGC.
2.
Check the interface wiring
Be sure the cable is good. Substitute a known good cable (IEEE 488 cables are available from
Granville-Phillips).
Check for too many devices on the bus or too great a total bus length (> 20 meters). Too many
devices could cause problems due to capacitive loading.
3.
Check the command syntax.
Be sure you are following the syntax specified in Section 7.3.
