Johnson Controls CDS-2000 Manual page 3

Pre-Verification
Information
S Sensors and Stats—CDS-2000 CO
Introduction
When properly installed, the CDS-2000 is accurate to ±100 ppm per year.
The calibration should be verified after the sensor has been in operation
for one full year and annually thereafter. Whenever an accuracy problem
is detected via the verification procedure, the sensor should be
recalibrated.
Before beginning the verification procedure, note the following:
• The CDS-2000 should be allowed to warm-up for at least one hour
before checking calibration or before calibrating. This will ensure that
the infrared sensor has reached an equilibrium temperature thereby
delivering maximum calibration accuracy.
• Recalibration of the device should not be attempted until after 14 days
of operation as the output may not have stabilized due to the drift
compensation algorithm. This variation should not be confused with
drift—it is the self-tuning of the algorithm.
• The microprocessor-based compensation algorithm is based on the
average of readings taken during a 30 minute or more "unoccupied"
period (less than 500 ppm) once every 24 hours during the previous
14 days. Readings are taken and stored in non-volatile memory. If the
power is removed, the readings will be retained.
• If after 14 days of operation the CDS-2000 appears to need
recalibration, obtain a CDS-2000-3 Calibration Kit, and perform the
single-point calibration procedure.
Sensor Verification, Calibration, and Troubleshooting Bulletin 3
2