3. Instruction Set
3-209
3. The forward running function of Delta’s VFD series inverter can also be set by handy
instruction API 102 FWD instruction through COM2/COM3 on PLC.
Program Example 5: COM1 RS-232
1. Only 8-bit mode is supported. Communication format and speed are specified by lower 8 bits
of D1036.
2. STX/ETX setting function (M1126/M1130/D1124~D1126) is not supported.
3. High byte of 16-bit data is not available. Only low byte is valid for data communication.
4. Write the data to be transmitted in advance into registers starting from D100 and set M1312
(COM1 sending request) as ON
5. When X10 = ON, RS instruction executes and PLC is ready for communication. D0 will then
start to send out 4 data continuously. When data sending is over, M1312 will be automatically
reset. (DO NOT apply RST M1312 in program). After approximate 1ms, PLC will start to
receive 7 data and store the data in 7 consecutive registers starting from D20.
6. When data receiving is completed, M1314 will automatically be ON. When data processing on
the received data is completed, M1314 has to be reset (OFF) and the PLC will be ready for
communication again. However, DO NOT continuously execute RST M1314, i.e. it is
suggested to connect the RST M1314 instruction after the drive contact M1314
Receiving completed and flag reset
Setting communication protocol as 9600,8,E,1
Retain communication protocol
Set up communication time out as 100ms
M1002
MOV H87 D1036
SET M1138
MOV K100 D1249
X0
RS
D100
K4
D120
K7
M1314
Processing received data
RST M1314
Pulse for
sending request
Pulse
Write transmitting data in advance
Sending request
SET
M1312
Sending data: (PLC→External equipment)
D100L D101L D102L D103L
Source data register, starting from
lower 8 bits of D100
Length = 4