MODBUS Domore

[jlretana72]

I'm using Domore PLC from automationdirect and working on Exercise 15 of the Tutorial Package Manager, What settings should I use on the Modbus driver window(analog Scale Factor and Analog Subtract factor) the solution for the exercise shows -.49, -.15, .69 and -.45.
Is there a formula. can you please show me how I can get decimals. Thank you

[EasyPLC_Master]

The Modbus protocol does not accept the management of decimal and/or negative numerical data. That is, it only allows positive integer values.
To solve this handicap, the EasyPLC/Machines Simulator ModBus driver offers two tools, the Analog Scale Factor and the Analog Subtract Factor.

The Analog Scale Factor: Divide or multiply the analog value by the indicated factor, in this way it is possible to send/receive decimal values that Modbus process in integer mode.
For example an Analog Scale Factor of 100 will act in the following mode: a sent value of 1.25 (from EasyPLC/Machines Simulator) will be read as 125 by Modbus device and an sent value of 245 (by Modbus devicce) will be processed as 2.45 for EasyPLC/Machines Simulator.

Analog Subtract Factor: after applying the Analog Scale Factor, the indicated value will be subtracted/added to obtain negative values. (Subtract Factor must be > 0).
For example an Analog Scale Subtract of 10 will act in the following mode: a received value of -10 (from MS) will be read as 0 in ModBus device system and a value sent of 0 (by ModBus device) will be processed as -10 for EasyPLC/Machines Simulator.

In this video from ACC Automation is perfectly explained:

[jlretana72]

Thank you for the quick answer.

to get -.49 Domore plc=9951  settings (Analog Scale Factor=100 and Analog Scale Subtract=100)
to get .69 Domore plc=10069  settings (Analog Scale Factor=100 and Analog Scale Subtract=100)
is this correct?

[EasyPLC_Master]

Yes, is correct!