VIN combined with CIN

Kevin 8 months ago in Master modules / MC4x updated by Gustav Widén (System support) 8 months ago 1

The MC43FS manual states that:

Note that for the MC4xFS, a voltage input combined with a current loop input is not
sufficiently diverse if the two signals are following each, the higher gain error has to be

Does this mean a single sensor measuring voltage (single output from the sensor) into a VIN and also current from the ground of the single sensor into a CIN? Is this what is defined as combined? ie. singe sensor, 2 inputs.

We are planning on using a single voltage output sensor providing a single VIN, and a separate sensor with 4-20mA signal output into a dedicated single CIN. Notes in the manual suggests we cannot do this because they are not crossed, even though they are independent sensors, different technologies and have separate wiring. What's the restriction and why, is it because it uses the same AD converters in the module? The pins are not shared (cannot be configured as voltage inputs or current inputs) so unsure of the reasons behind this.

Just looking for clarification really as the statement seems to suggest we may be able to if....'the higher gain error has to be
considered'? Both the sensors we are planning on using are not crossed (signal outputs increase as pressure rises, one voltage the other current).


The gain error the note refers to is the 10% error your application must be able to tolerate to use signals that are not crossed, the safety requirements:

C4x-SMR-016:A Tolerances on single or identical VIN

C4x-SMR-022:A Tolerances on single or identical CIN