RKI Instruments 65-2507RK - Manual (Page 16)

12 • 65-2507RK Oxygen Transmitter
Calibration
This section describes how to calibrate the oxygen transmitter. It includes procedures to
prepare for calibration, set the fresh air reading, set the zero reading, and return to normal
operation. It describes the test using a calibration kit that includes a calibration cup,
calibration gas, sample tubing, and a fixed flow regulator with an on/off knob. RKI
Instruments, Inc. recommends using a 0.5 LPM (liters per minute) fixed flow regulator.
NOTE: Calibrating the oxygen transmitter may cause alarms. Be sure to put the
controller into its calibration program or disable external alarms before
continuing.
Preparing for Calibration
1. Unscrew and remove the junction box cover.
2. Set a voltmeter to measure in the millivolt (mV) range.
3. Plug the positive lead into the test point labeled TP+; plug the negative lead into the
test point labeled TP-.
4. Slide the calibration cup over the bottom of the oxygen detector, then secure the
calibration cup to the detector with the thumb screw.
Setting the Fresh Air Reading
NOTE: If you can verify that the oxygen transmitter is in a fresh air environment, you do
not need to apply zero air to the detector before adjusting the zero reading.
1. Screw the regulator into the zero air calibration cylinder.
2. Use the sample tubing to connect the regulator to the calibration cup.
3. Turn the regulator knob counterclockwise to open the regulator.
4. Allow the gas to flow for 2 minutes.
5. Verify a voltmeter reading of 434 mV (±2 mV).
6. If necessary, use a flat-blade screwdriver to adjust the span pot on the amplifier until
the voltmeter reading is 434 mV (±2 mV).
7. Turn the regulator knob clockwise to close the regulator.
8. Unscrew the regulator from the zero air calibration cylinder.
9. Leave the sample tubing connected to the regulator and the calibration cup.
NOTE: Depending on the size of your zero air cylinder, it is possible that you will have a
different regulator for the zero air cylinder and the 100% nitrogen cylinder. If
necessary to fit the nitrogen cylinder, change the regulator.
Setting the Zero Reading
1. Screw the regulator into the 100% nitrogen calibration cylinder.
2. Turn the regulator knob counterclockwise to open the regulator.
3. Allow the gas to flow for two minutes and verify a reading of 100 mV (±2 mV).