A set of 16 modbus requests that can be sent to an RTU on either an RS232 or RS485 serial port. The internal registers are referenced for this purpose.
Each of the enabled polls in the set are executed sequentially. There is a configurable delay between polls. If a poll error occurs the bits in an analog internal register are set to identify which polls failed.
Each row defines one modbus master request. These are defined in the order they are sent to the RTU. The modbus requests are used to transfer registers between the master and slave. The terminal is the master and the RTU is the slave.
| Reg | Type of register: coils, status, inputs, holdings. If 'None' the poll is unused and removed when it is saved to a file. |
| Int Reg | Internal register number. See internal registers . |
| Slv Reg | Slave register number. |
| Num Reg | Number of registers to transfer. For a 32 bit register this is set to 1 to transfer one register. |
| Reg Len | Number of bits in a register value. 1, 16, 32. |
| Function | Function code of the generated modbus request. |
| RTU ID | Slave identifier of the generated modbus request. 1 to 247. |
| Com Port | Serial port to access attached RTUs. |
| Delay | Time to wait between polls in the set of polls (.1 sec). |
| Timeout | No response timeout in milliseconds. |
| Fail Tries | Number of attempts before giving up. |
| Status | OK and green if the last poll worked. FAIL and red if the last poll did not work. Blank if the Get Status button was not clicked. Blank if the Clear Status button was clicked. |
The check box must be selected if this row is to be used to generate a modbus master request. If it is not the row is still saved in the terminal but is not used.
The Reg field is used to remove polls from the set. By selecting 'None' the poll will be eliminated when a File > Save or File > Save As is invoked. After opening the config file with File > Open the polls with Reg set to None will all be removed.
The 16 polls are displayed on two forms each having 8 polls. To move between the forms use the slider on the right.
Polling can be controlled and monitored with these:
| Enable Polling | Takes precedence over the individual poll enable check boxes. Used to disable and re-enable the entire set of polls. |
| Get Status | Get poll status from terminal. Status of last executed poll group. |
| Clear Status | Clear poll status in table. |