9 Application Instructions API 150-199 Remarks: 1. The activation condition placed before MODRD, RDST and MODRW instructions cannot use rising-edge or 2. PLC COM1 ~ COM3: Please refer to API 80 RS for more information about the associated flags (Auxiliary falling-edge contacts; otherwise the data stored in the registers for received data will encounter errors. relays) and special registers (Special D) for the communication instruction MODRW. 3. PLC COM2 RS-485:
Associated flags (Auxiliary relays) and special registers (Special D) for the communication instruction MODRW DVP-PLC Application Manual 9-31 Register Data Description D3001 1766 H PLC-A converts data in 1101H and stores the converted data automatically. Flags Function M1120 For retaining communication setups. After the setup is made, changes in D1120 will be invalid. M1121 When Off, RS-485 is sending data. M1122 Sending request M1123 Receiving is completed M1124 Waiting for receiving data M1125 Disable receiving status M1126 Selecting STX/ETX system M1127 Sending/receiving data through MODRD / RDST / MODRW instructions is completed. M1128 Sending data…/receiving data…
M1129 Receiving data time-out M1130 User/system defined STX/ETX M1131 On when MODRD / MODWR / MODRW is converting data to hex M1140 MODRD / MODWR / MODRW data receiving error M1141 MODRD / MODWR / MODRW parameter error M1142 VFD-A handy instruction data receiving error M1143 ASCII/RTU mode selection (used with MODRD/MODWR/MODRW) (Off = ASCII mode; On = RTU mode) D1070 ~ D1085 When the built-in RS-485 communication instruction is executed and sends out data, the receiving end will respond with a message and the message will be stored in D1070 ~ D1085. The user can check the registers for the messages.
D1120 RS-485 communication protocol D1121 PLC communication address (saving PLC communication address; latched) D1122 Remaining words of the sent data D1123 Remaining words of the received data D1124 Start text definition (STX) D1125 Definition of end text 1 (ETX1) D1126 Definition of end text 2 (ETX2)