Can the Robertshaw DMS T99 sensor be connected to a MNL controller using the curve fit object?

Issue

Can the Robertshaw DMS T99 sensor be connected to a MNL controller using the curve fit object?

Product Line

TAC I/A Series

Environment

  • WorkPlace Tech
  • Robertshaw DMS T99
  • MNL controller

Cause

Site require the use of Robertshaw DMS T99 sensor with MNL controller.

Resolution

The T99 sensor is a 2000 ohm silicon-based RTD with linearity similar to the Balco. Wire this sensor to the MNL controller's UI with a parallel 2000 ohm 1% shunt resistor and use the AI object's Balco type selection. The AI object's output temperature values can then be corrected by using a Curve Fit object.

Set the Curve Fit X and Y data points as follows. The X points reflect Balco temperatures and the Y points reflect the corrected T99 sensor temperatures. Note that the A/D degree per count resolution is twice the Balco's which calculates to approximately 0.15 Degrees F per A/D count change.

  • X Data
  • Points 1 to 6 are 52.5, 61.6, 70.0, 78.4, 86.6, and 94.8.
  • Y Data
  • Points 1 to 6 are 32.0, 50.0, 68.0, 86.0, 104.0, and 122.0.