I am reading the 4 variables from the connected HART protocol devices from a Phoenix Contact GW PL ETH unibus and a GW PL HART4 unit.
The HART4 unit is connected on 4 HART signals from devices.
De Phoenix GW PL ETH collects all main variables and they are available in input registers in the Phoenix unit, readable with the ModbusTCP library from NI.
Next step is to individual read the devices and ask for device info.
To read an individual device I must use command 77 with an ID.
Is there anyone familiar with this function code and how can I use the standard NI Modbus lib to read the information?