User Manual
Chapter 12
GFK-1503F
Jan 2020
Serial I/O / SNP / RTU Protocols
218
VALUE
(decimal)
VALUE
(hexadecimal)
MEANING
a5
0000
0000
Not used
a6
4304
10D0
Write port control command
a7
xxxx
xxxx
Port control word
Port Control Word
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTS
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
The Port Control Word can be:
15
RTS
Commanded state of the RTS output
1 = Activates RTS
0 = Deactivates RTS
0-14
U
Unused (should be zero)
Operating Note
For CPU port 2 (RS-485), the RTS signal is also controlled by the transmit driver. Therefore,
control of RTS is dependent on the current state of the transmit driver. If the transmit driver
is not enabled, asserting RTS with the Write Port Control COMMREQ will not cause RTS to
be asserted on the serial line. The state of the transmit driver is controlled by the protocol
and is dependent on the current Duplex Mode of the port. For 2-wire and 4-wire Duplex
Mode, the transmit driver is only enabled during transmitting. Therefore, RTS on the serial
line will only be seen active on port 2 (configured for 2-wire or 4-wire Duplex Mode) when
data is being transmitted. For point-to-point Duplex Mode, the transmit driver is always
enabled. Therefore, in point-to-point Duplex Mode, RTS on the serial line will always reflect
what is chosen with the Write Port Control COMMREQ.
12.4.9
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)
a1
0000
0000
NOWAIT mode
Содержание PaCSystems VersaMax Series
Страница 1: ...User Manual GFK 1503F Jan 2020 PACSystemsTM VersaMax PLC USER MANUAL ...
Страница 85: ...User Manual Chapter 7 GFK 1503F Jan 2020 CPU Operation 71 7 1 Parts of the CPU Sweep Figure 47 ...
Страница 284: ...User Manual Chapter 14 GFK 1503F Jan 2020 PID Built in Function Block 270 Figure 216 ...