Modbus Peripheral Holding Registers
From embeddedTS Manuals
The interface to all Modbus peripheral devices consists of a set of 127 holding registers. These registers are used to configure the device operation, read and write input output parameters, as well as various settings used to configurable Modbus Address, Termination enable, Data Format, and Bit Rate. These settings are common to all of our Modbus peripherals and can be persisted in on-board flash memory.
NOTE: The device operates ONLY in Modbus RTU communications mode. Modbus ASCII is not presently supported.
| Address (hex) | Address (dec) | Access | Description | Example Values |
|---|---|---|---|---|
| 0x70 | 112 | Read/Write | Modbus Mode | 0 = ASCII (unimplemented), 1 = RTU |
| 0x71 | 113 | Read/Write | RS485 Bus Termination Enable | 0 = Termination disabled, 1 = Termination enabled |
| 0x72 | 114 | Read/Write | Modbus Device Address | 0-247 (0x00-0xf7) 0 = Broadcast |
| 0x73 | 115 | Read/Write | Modbus bit rate | Bit Rate |
| 0x74 | 116 | Read Only | Unit Model | e.g., 0x1400, 0x1700, 0x1800, etc |
| 0x75 | 117 | Read Only | Verilog Version | e.g., 1 |
| 0x76 | 118 | Read Only | ZPU Version | e.g., 1 |
| 0x77 | 119 | Read Only | Bus power Supply in millivolts | e.g., 23600 |
| 0x78 | 120 | Read Only | Internal Temperature in 1/100th degree Celsius | e.g., 290 |
| 0x79 | 121 | Read/Write | Reserved or model specific | Not applicable or model specific |
| 0x7a | 122 | Read/Write | Reserved or model specific | Not applicable or model specific |
| 0x7b | 123 | Read/Write | Reserved or model specific | Not applicable or model specific |
| 0x7c | 124 | Read/Write | Reserved or model specific | Not applicable or model specific |
| 0x7d | 125 | Read/Write | Write listed value to persist communications (Bit rate, Data format, Address, and Termination) parameters to internal nonvolatile storage: | 0xFEED = Persist configuration, 0xDEAD = Erase configuration, 0xC0DE apply configuration without persistence. In all cases the value is set to zero when completed or 0xFA17 (FAIL) if error. |
| 0x7e | 126 | Read/Write | Reserved or model specific | Not applicable or model specific |
NOTE: All Read Only registers may be written; however, writing to certain registers (e.g., Unit Model) will overwrite the information that will not be refreshed until the unit is reset.