I need to determin the resolution of an a to d converter used by an AB system Micro logix 1200. Also how does this relate to the word length
used?

 

The resolution of a signal is a measure of how well you can represent a physical or analog signal.

For example, for a 12 bit word like in AB PLC-5 you have a resolution of 2 to the 12th or 4096 "steps".

If you are measuring temperature in the 0 - 100 degress, then:

100 / 4096 = 0.0244 deg per step.

That means that if you need resolution of 0.01 deg, this 12 bit channel will not help you.

 

The Micrologix 1200 analog conversions are 15bit plus a sign bit for bipolar indication i.e. -32767 to +32676.