ET-7000/PET-7000 User Manual, version 1.1.0 III
3.5. I/O Pair Connection ....................................................................................... 74
3.5.1. Example 1: Pair Connection - AO to AI .................................................... 76
3.5.2. Example 2: Pair Connection - DO to DI .................................................... 81
3.6. More Information .......................................................................................... 84
4. Modbus and Modbus TCP/IP ................................................................. 86
4.1. Modbus TCP/IP Interface ............................................................................... 87
4.2. Protocol Description ...................................................................................... 88
4.3. Data Encoding ................................................................................................ 91
4.3.1. Binary ...................................................................................................... 91
4.3.2. 16-bits Word ............................................................................................ 91
4.4. Data Model .................................................................................................... 92
4.5. Modbus Functions and Register Addresses ................................................... 93
4.5.1. 01 (0x01) Read Coils ................................................................................ 93
4.5.2. 02 (0x02) Read Discrete Inputs ................................................................ 94
4.5.3. 03 (0x03) Read Holding Registers ............................................................ 95
4.5.4. 04 (0x04) Read Inputs Registers .............................................................. 96
4.5.5. 05 (0x05) Write Single Coil ...................................................................... 97
4.5.6. 06 (0x06) Write Single Register ............................................................... 98
4.5.7. 15 (0x0F) Write Multiple Coils ................................................................. 99
4.5.8. 16 (0x10) Write Multiple Registers ........................................................ 100
4.6. Modbus Master Simulators .......................................................................... 101
4.6.1. Modbus/TCP Client ............................................................................... 101
4.6.2. Modbus Master Tool ............................................................................. 103
4.7. Modbus Demo Programs ............................................................................. 106
5. Calibration .......................................................................................... 107
5.1. Voltage and Current Calibration................................................................... 107
5.2. Thermocouple Calibration ........................................................................... 112
5.3. RTD Calibration ............................................................................................ 113
5.4. Recover Calibration to Factory Setting ......................................................... 115