3. Instruction Set
3-251
9. Please refer to the points to note below for more information about the flags and the special
data registers which are related to RS-485 communication instructions.
10. Communication instructions including MODRW/MODWR/MODRD/RS should be used with flags
including M1312/M1122/M1316. Set the flags first and then execute the communication
instruction.
11. Executing RS instruction with the newly added M1263, you can set the data receiving as
completed when the stop between data receiving is longer than what is set in D1168, only
available for COM2. Refer to Program Example 7 below for more details. The supporting
models are shown below:
Program Example 1: COM2 RS-485
1. Write the data to be transmitted in advance into registers starting from D100 and set M1122
(Sending request) as ON.
2. When X10 = ON, RS instruction executes and PLC is ready for communication. D100 will then
start to send out 10 data continuously. When data sending is over, M1122 will be automatically
reset. (DO NOT apply RST M1122 in program). After approximate 1ms, PLC will start to receive
10 data and store the data in 10 consecutive registers starting from D120.
3. When data receiving is completed, M1123 will automatically be ON. When data processing on
the received data is completed, M1123 has to be reset (OFF) and the PLC will be ready for
communication again. However, DO NOT continuously execute RST M1123, i.e. it is suggested
to connect the RST M1123 instruction after the drive contact M1123.
MOV
D1120
H86
M1002
SET M1120
MOV D1129K100
X0
M1123
RST M1123
RS D100 K10 D120 K10
Pulses for
sending request
Pulse
Receiving
completed
Set up communication protocol as
9600, 7, E, 1
Retain communication protocol
Set up communication time-out as 100ms
Write transmitting data in advance
Sending request
Processing received data
Reset M1123
SET
M1122
Models ES2/EX2
ES2-C ES2-E 12SA2
SX2 SS2 12SE 26SE 28SA2
V4.02 V3.8 V1.48 V3.04 V3.04 V4.02 V2.06 V2.06 V2.90
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