7 Application Instructions API 50-99 Program Example 6: COM3 RS-485 or RS-232 1. Only 8-bit mode is supported. Communication format and speed are specified by lower 8 bits of D1109. 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 M1316 (COM3 sending request) as ON 5. When X0 = ON, RS instruction executes and PLC is ready for communication. D100 will then start to send out 4 data continuously. When data sending is over, M1316 will be automatically reset. (DO NOT apply RST M1316 in program).
After approximate 1ms, PLC will start to receive 7 data and store the data in 7 consecutive registers 6. When data receiving is completed, M1318 will automatically be ON. When data processing on the received data starting from D120. is completed, M1318 has to be reset (OFF) and the PLC will be ready for communication again. However, DO NOT continuously execute RST M1318 . M1002 Setting communication protocol as 9600,8,E,1 Retain communication protocol Set up communication time out as 100ms Pulse for sending request Pulse Write transmitting data in advance Sending request X0 M1318 Processing received data Receiving completed and flag reset Sending data:
(PLC → External equipment) Source data register, starting from lower 8 bits of D100 Length = 4 DVP-PLC APPLICATION MANUAL 7-104 MOV H87 D1109 SET M1136 MOV K100 D1252 SET M1316 RS D100 K4 D120 K7 RST M1318 D100L D101L D102L D103L