What is the resolution of our various controllers Inputs and Outputs?

[Product_Support]

Issue

Need to know the smallest change that an Input can measure or that an Output can provide.

Environment

All Continuum controllers.

Cause

Need to know for specification compliance or to determine the smallest measurable change in an Input.

Resolution

Some of our controllers support inputs with a 10 bit resolution and some support 12 bit resolution. As a rule, all 5.115v inputs are 10 bit and all 10v inputs are 12 bit.

You can see which resolution each controller supports by viewing the Datasheet for each controller and noting the value of the "Input Resolution" and voltage range of the inputs (normally 0-10VDC).

As an example, the b3920 shows an input resolution of 2.5mV on its 0-10VDC inputs. This equates to a 12 bit resolution as shown below.

     2^x = 10VDC / 0.0025 VDC
     2^x = 4000
     x * log(2) = log(4000)
     x = log(4000) / log(2)
     x = 11.96578 or 12 bit
 

Further, a b3800 has an input resolution of 10 bits on its 0-5.115VDC inputs.

     5VDC / 2¹⁰ = 0.00499V or 5 mV

You can find the individual controller Datasheets on Ecobuildings. Navigate to the Download Center and search the controller model number. Then narrow results by Asset Type = 'Specification Sheet'.  Most of the new Datasheets now note both the Input and Output resolutions.