Issue
Current transducers require an additional external resistor fitting to a Universal input to read the current flow, what resistor and input point settings are required?
Environment
All controller with Universal Inputs (both 5V and 10V).
4-20 mA
Cause
There is a requirement to define the resistor value to be connected across the input, also the settings for the upper and lower voltage in the input point configuration.
Resolution
Download the attached Current Inputs.PDF file, although this was originally written for Infinity controllers it is fully applicable for i2 and b3 controllers. Controllers like the i2/b3920, i2/b3810 have 10V inputs other i2/b3 controllers have 5.12V inputs, check the product datasheet specification if you are unsure.
The file details the value of the resistor to use in the circuit and the upper and lower voltage settings to enter in the Auto Conversion box in the input point, these will correspond to the sensor reading at 0mA and 20mA, or 4mA and 20mA depending on your sensor output.
For controllers that allow the pull up resistor to be switched out, ensure that it is in circuit for these setting to work correctly.
The UI-8-10-10V I/O Modules should be set to 0-5V input with the reference resistor On, then setup as per all other 5.12V input controllers.
Note: The part numbers listed for the resistors are no longer available through Order Entry and should be sourced from your local stockist.
Link to file:
Suitable component resistors:
For 10V inputs: RS 165-472
For 5V inputs: RS 165-185
