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+--- Thread: Strange modbus scaling (/showthread.php?tid=6354)
Strange modbus scaling - Ceros2112 - 17.03.2026
Hello,
I have a modbus device that scales values in a strange way and I don't know how to make it work, if possible, with LM5.
Basically the formula is: (value+5)*2+30, in other words it reads values from -20 to 100 and represents values from 0 to 240
so, for example, if the value read by the instrument is -20, via modbus I will read 0.
Any ideas on how to integrate it in a json modbus profile?
RE: Strange modbus scaling - admin - 17.03.2026
value_base = -20
value_multiplier = 0.5
Formula:
value = value_base + value * value_multiplier
value = -20 + value * 0.5
If read value is 0 the resulting value is -20. If read value is 240 the resulting value is 100.
RE: Strange modbus scaling - Ceros2112 - 17.03.2026
thanks! I've tried it before but I must have done something wrong