DVP-ES3 Series Programming Manual 7. There is no limitation on the number of times you can use this instruction; however only one instruction can be executed on the same COM port at a time. You need to decide and use the sending flag for the COM to be used before executing this instruction. Otherwise, the data from 2 different communication COMs may be mixed up. 8. If a communication timeout occurs, the timeout flags are ON. After you solve the problem, you must reset timeout flags to OFF. When using this instruction, the timeout value cannot 0. Set the value between 100–32767ms; when the value is set to 0, it is processed as 200 ms. 9.
In Modbus ASCII mode, you need to set up only the data (non-ASCII mode) for transmission. The instruction checksum (LRC) and tail code (CRLF). The instruction stores the data received in ASCII character in the internal converts the non-ASCII mode to the ASCII mode, consisting of the head code (:), the converted ASCII code, _6 register. The PLC automatically converts the data into the hexadecimal value, and if the communication data is correct, stores the conversion result in S . and sets the completion flag SM to ON. 10. In Modbus RTU mode, you need to set up only the data for transmission.
The instruction adds the checksum (CRC) into the hexadecimal value, and if the communication data is correct, stores the conversion result stored in S . and the stores the data received in ASCII character in the internal register. The PLC automatically converts the data 11. The instruction cannot be used in the ST programming language, interrupt tasks or function block which is called only once. Communication protocol setup example 1. The following examples use PLC communication port 1 and special registers to demonstrate how to setup a communication protocol. 2.
You can set up the PLC communication port with HWCONFIG in ISPSoft, or with the relative special registers, or you can use the COMDF instruction (API 1813) to set up the communication. Please refer to the ISPSoft manual for setting it up in HWCONFIG. For communication register setups (SM, SR), please refer to section 6.19.3 for more details.
6-534 Function S3 S n code data is written 16#06 Address into where the data is written Register where the data written is stored No meaning 16#0F Address into where the data is written Register where the data written is stored Length of data written 16#10 Address into where the data is written Register where the data written is stored Length of data written