Simulating Input Currents - Dissolved Oxygen; Simulating Input Currents - Chlorine And Ozone; Simulate Dissolved Oxygen; Simulate Chlorine And Ozone - Emerson Rosemount Analytical HART 5081-A-HT Instruction Manual

MODEL 5081-A

16.9 SIMULATING INPUT CURRENTS - DISSOLvED OxyGEN

To check the performance of the transmitter, use a decade box to simulate the current from the oxygen sensor.
A. Disconnect the anode and cathode leads from terminals 13 & 14 and connect a decade box as shown in Figure 16-1.
It is not necessary to disconnect the RTD leads.
B. Set the decade box to the resistance shown in the table.
Sensor
499ADO
499ATrDO
Hx438 and Gx448
C. Note the sensor current. To view the sensor current, go to the
main display and press DIAG. Then press NEXT. SEnSor
Cur will appear in the display. Press ENTER. The display will
show the sensor current. Note the units: µA is microamps:
nA is nanoamps.
D. Change the decade box resistance and verify that the correct
current is shown. Calculate the current from the equation:
current (µA) =

16.10 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.
A. Disconnect the anode and cathode leads from terminals 13 & 14 and connect a decade box and battery as shown in
Figure 16-2. It is not necessary to disconnect the RTD leads.
B. Set the decade box to the resistance shown in the table.
Sensor
499ACL-01 (free chlorine)
499ACL-02 (total chlorine)
499AOZ
C. 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, go to the main display and press DIAG. Then, press NEXT. SEnSor Cur will appear
in the display. Press ENTER. The display will show the sensor current. Note the units: uA is microamps: nA is
nanoamps.
D. Change the decade box resistance and verify that the correct
current is shown. Calculate the current from the equation:
current (µA) =
The voltage of a fresh 1.5 volt battery is about 1.6 volt (1600 mV).
Polarizing voltage
-675 mV
-800 mV
-675 mV
voltage (mV)
resistance (kW)
Polarizing voltage
200 mV
250 mV
200 mV
V – V (mV)
battery polarizing
resistance (kW)
Resistance
34 kW
20 kW
8.4 MW
FIGURE 16-1. Simulate dissolved oxygen.
Resistance
28 MW
675 kW
2.7 MW
FIGURE 16-2. Simulate chlorine and ozone.
SECTION 16.0
TROUBLESHOOTING
Expected Current
20 µA
40 µA
80 nA
Expected Current
500 nA
2000 nA
500 nA
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