4. Change the decade box resistance and verify that the correct current is shown.
Calculate the current from the equation:
8.4.10 Simulating input currents - chlorine and ozone
To check the performance of the transmitter, use a decade box and a battery to simulate
the current from the sensor. The battery, which opposes the polarizing voltage, is
necessary to ensure that the sensor current has the correct sign.
1. Disconnect the anode and cathode leads from terminals 13 and 14 and connect a
decade box and battery as shown in Figure 8-12.
It is not necessary to disconnect the RTD leads.
Simulate chlorine and ozoneFigure 8-12:
2. Set the decade box to the resistance shown in the table.
Sensor Polarizing voltage Resistance Expected current
499ACL-01 (free
chlorine)
200 mV 28 MΩ 500 nA
499ACL-02 (total
chlorine)
250 mV 675 kΩ 2000 nA
499AOZ 200 mV 2.7 MΩ 500 nA
3. Note the sensor current. It should be close to the value in the table. The actual value
depends on the voltage of the battery. To view the sensor current:
a. Go to the main display and press DIAG.
b. Press NEXT.
SEnSor Cur appears in the display.
Diagnostics and troubleshooting
Instruction Manual 113
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