I have to write setpoint on Honeywell UDC3200 with PLC Unitronics V120. I have only function 6 or 16 to do that.
I try to write setpoint real format on 7D. Display change: auto mode disappear but setpoint stay on C1, and output shutdown to 0 because parameter Hight limit output change to 0.
Parametter of communication:
- COMSTA: modbus
- IRENABLE: valide
- VITBAUD: 19200
- DEL TRAN: 1
- WS FLOAT: FP B
- shedenab : valide
- TPS DELE: 30
- MODE DEL: en AUTO
- C REPLI: en COL
- UNITE: SCIENT
- RATO CPC: 1.00
- BIAS CPC: 0.0
- ECHO: INACTIVE.
Could you help me?
I'll bet you took the register address from the UDC 3200 product manual, which is absolutely unuseable - that Modbus map and those register/addresses are for FC20/21 configuration settings. Nothing in the product manual applies to ordinary day-to-day user Modbus.
Use the Modbus RTU Serial Communications User manual at the link below, not the 3200 product manual. The Modbus slave register/address map/table and other Modbus infor that you need is in the Modbus RTU Serial Communications User Manual. 51-52-25-66, the latest edition is rev T.
To write a floating point value, you need to use Function Code 10h, 16 decimal, according to the table on pg 18:
FC 06 writes a single register only, only half of a floating point value.
As the map from the Rev T manual says, the working setpoint is at 0044h or (4)0069 decimal
Writing two registers to 007D, writes half a floating point to the Output high limit value and half a floating point value to Output working value.
Oops. My mistake.
(4)0069 is the read-only working SP. Can't write to that register.
Write a floating point value to the working SP at (4)0121, 0078h