Flush Input Buffer Function (4302); Read Port Status Function (4303) - Emerson PACSystems RX3i User Manual

PACSystems™ RX3i and RSTi-EP CPU Reference Manual
GFK-2222AK
6.2.7.1 Retrieving Data from the Buffer
Data can be retrieved from the buffer using the Read String or Read Bytes function. It is
not directly accessible from the application program.
If data is not retrieved from the buffer in a timely fashion, some characters may be lost.
6.2.7.2 Example Command Block for the Set Up Input Buffer
Function
Address
Address +1 0000
Address +2 0008
Address +3 0000
Address +4 0000
Address +5 0000
Address +6 4301
Address +7 0064
6.2.8

Flush Input Buffer Function (4302)

This operation empties the input buffer of any characters received through the serial port
but not yet retrieved using a read command. All such characters are lost.
6.2.8.1 Example Command Block for the Flush Input Buffer Function
Address
Address +1 0000
Address +2 0008
Address +3 0000
Address +4 0000
Address +5 0000
Address +6 4302
6.2.9

Read Port Status Function (4303)

This function returns the current status of the port. The following events can be detected:
1. A read request was initiated previously and the required number of characters has
now been received or the specified time-out has elapsed.
Serial I/O, SNP & RTU Protocols
VALUE VALUE
(decimal) (hexadecimal) MEANING
0002 0002
0000
0008
0000
0000
0000
10CD
0040
VALUE VALUE
(decimal) (hexadecimal)
0001 0001
0000
0008
0000
0000
0000
10CE
Data block length
NOWAIT mode
Status word memory type (%R)
Status word address minus 1 (%R0001)
Not used
Not used
Setup input buffer command
Buffer length (in words)
MEANING
Data block length
NOWAIT mode
Status word memory type (%R)
Status word address minus 1 (%R0001)
Not used
Not used
Flush input buffer command
Section 6
October 2019
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