Basic Operations on Data

[egekorkan]

In some devices (mostly Modbus), there is this nice trick where the value needs some basic math operations.

• The value on the wire is 241 but it actually represents 24.1, so it should be multiplied by 0.1. This is to save the need to handle digits. This is typically called slope or scale.
• The value on the wire is 5 but it actually represents -5, so it should be substracted by 10. This is to save the need to handle negative numbers. This is typically called offset

If there are other protocols that have this behavior, we can think of standardizing it in the data schema level. Otherwise, these can be form terms in modbus binding

[sebastiankb]

Yes, that is quite typical. Factors such as multipliers or offsets are usually stored in a specific register.