Johnson Controls CDS-2000 Manual page 10

10 S Sensors and Stats—CDS-2000 CO
5. Use tubing to connect the 0 ppm gas to the CDS-2000's tubing port
shown in Figure 1. (Refer to the instructions in the Verification—
Procedure section as needed.) Slowly adjust the regulator valve to
flow gas into the sensor. Continue flowing the gas until a stable
reading is reached at the DVM. (This will take about 2 minutes at
500 ml/min.) When a stable reading is achieved at the DVM, use the
small-blade screwdriver to slowly adjust the recessed zero
adjustment potentiometer (to the left of SW-1, see Figure 1) until the
DVM reads between 2.75 and 2.85 VDC. Turn Clockwise (CW) to
decrease or Counterclockwise (CCW) to increase.
Note: A 0.2 V, 1 Hz signal is superimposed on the DC level. The
2.8 VDC value should correspond with the highest of the two
values, which alternate on the DVM readout.
6. Press the SW-1 button until the LED gives three quick flashes and a
momentary dark pause (the LED will then flash continuously).
Release the button, and flow 2000 ppm CO
a stable reading is reached (between 0.4 and 0.8 volts).
7. When a stable reading is achieved (will take about 2 to 3 minutes),
press the SW-1 button to return the unit to the Primary mode (LED
flashes continuously). If the 8 (+) lead of the DVM is moved to
Terminal 1 at this point, the DVM should read between 9.5 and 10.5
VDC. (If not, refer to the Troubleshooting section.) Disconnect the
DVM.
8. Reconnect the flow pickup device if using the CDS-2000-1. Remove
the silicone blanket and metal clips if using the CDS-2000-2.
Sensor Verification, Calibration, and Troubleshooting Bulletin
2
gas into the sensor until
2