9 Application Instructions API 150-199 Register (D0) for PLC1 received data (responding messages): 3. RTU Mode: When PLC1 is connected to PLC2 When X10 = On, function code 02 of MODRW instruction will start to be executed. PLC1 PLC2, PLC1 sends: “ 01 02 0500 0010 79 0A ” PLC2 PLC1, PLC1 receives: “ 01 02 02 34 12 2F 75 ” Registers for PLC sent data (sending messages): Register (D0) for PLC received data (responding messages): Program Example 2: COM1(RS-232) / COM3(RS-485), Function Code H02 1. Function code K2 (H02): read multiple bit devices. Up to 64 bits can be read. 2. PLC1 connects to PLC2: (M1320 = OFF, ASCII mode), (M1320 = ON, RTU mode) 3.
For both ASCII and RTU modes, PLC COM1/COM3 only stores the received data in registers starting from S , and will not store the data to be sent. The stored data can be transformed and moved by using DTM instruction for applications of other purposes. 4. Take the connection between PLC1 (PLC COM3) and PLC2(PLC COM1) for example, the tables below explains the status when PLC1 reads Y0~Y17 of PLC2 If PLC1 applies COM1 for communication, the below program can be usable by changing:
DVP-PLC Application Manual 9-5 Register DATA Explanation D0 Low ‘0’ 30 H ADR 1 ADR 0 D0 High ‘1’ 31 H D1 Low ‘0’ 30 H CMD 1 CMD 0 D1 High ‘2’ 33 H D2 Low ‘0’ 30 H Number of data (counted by bytes) D2 High ‘2’ 32 H D3 Low ‘3’ 33 H Content in address 0500 ~ 0505 PLC automatically convert ASCII words and store the result in D1296 = H1234 (b0 ~ b5 are valid) D3 High ‘4’ 34 H D4 Low ‘1’ 31H D4 High ‘2’ 32H D5 Low ‘B’ 52H LRC CHK 1 D5 High ‘5’ 35 H LRC CHK 0 Register DATA Explanation D1256 low 1 H Address D1257 low 2 H Function D1258 low 5 H Starting data address D1259 low 0 H D1260 low 0 H Number of data (counted by words) D1261 low 10 H D1262 low 79 H CRC CHK Low D1263 low 0A H CRC CHK High Register DATA Explanation D0 low 01 H Address D1 low 02 H Function D2 low 02 H Number of data (byte) D3 low 34 H Content in address 0500H PLC automatically stores the value in D1296=H1234 (b0 ~ b5 are valid) D4 low 12 H D5 low 2F H CRC CHK Low D6 low 75 H CRC CHK High