GE PACSystems RX7i Reference Manual

Chapter 6. Serial I/O, SNP & RTU Protocols
218 PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual GFK-2222AD
6.2.11 Cancel COMMREQ Function (4399)
This function cancels the current operations in progress. It can be used to cancel both read operations
and write operations.
If a read operation is in progress and there are unprocessed characters in the input buffer, those
characters are left in the input buffer and available for future reads. The serial port is not reset.
Example Command Block for the Cancel Operation Function
Value
(decimal)
Value
(hexadecimal)
Meaning
Address
0002
0002
Data block length (2)
Address +1
0000
0000
NOWAIT mode
Address +2
0008
0008
Status word memory type (%R)
Address +3
0000
0000
Status word address minus 1 (%R0001)
Address +4
0000
0000
Not used
Address +5
0000
0000
Not used
Address +6
4399
112F
Cancel operation command
Address +7
0001
0001
Transaction type to cancel
1 - All operations
2 - Read operations
3 - Write operations
Operating Notes
Remote COMMREQs that are cancelled due to this command executing will return a COMMREQ status
word indicating request cancellation (minor code 12H).
Caution
If this COMMREQ is sent in either Cancel All or Cancel Write
mode when a Write Bytes (4401) COMMREQ is transmitting a
string from a serial port, transmission is halted. The position
within the string where the transmission is halted is
indeterminate. In addition, the final character received by the
device to which the CPU is sending is also indeterminate.

GE PACSystems RX7i Specifications

General

Brand	GE
Model	PACSystems RX7i
Category	Controller
Language	English