Rosemount 54E, Инструкция по эксплуатации

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MODEL 54e pH/ORP SECTION 8.0
TROUBLESHOOTING
PREAMPLIFIER TROUBLESHOOTING
PROCEDURE
Use this procedure when diagnosing the circuit which
carries the signal from the sensor. There are 3 sepa-
rate procedures, depending on where the preamplifi-
er is located.
A. Preamp in a junction box (Figure 8-2)
1. Verify that the controller's preamp switch is in the
sensor/J box position (see Figure 2-5).
2. Remove the cover of the junction box.
3. Disconnect the BNC adapter or remove leads
from TB1-7 and TB1-10 (whichever is connected).
4. Install a jumper between 7 and 10, 3 and 4, and
7 and 8 (see Figure 8-2).
5. The controller should now read approximately
7 pH.
NOTE
If the controller has been calibrated with a
large zero offset, the pH may not be close
to 7. In this case, standardize the controller
at 7. (Section 3.4).
6. If the controller does not read correctly (after
standardizing, if necessary), go to step B.
B. Controller preamp check (Figure 8-3)
1. Disconnect all sensor wiring from the controller
at TB2.
2. Verify that the preamp location switch is in the
analyzer position, and that temperature compen-
sation is set to manual at 25°C or 77°F (see
Section 3.5).
3. Jumper TB2-3 to TB2-4 and TB2-7 to TB2-8.
4. Jumper TB2-7 to TB2-10 to simulate 7 pH.
5. The controller should now read 7 pH (or 0 mV in
ORP mode).
NOTE
If the controller has been calibrated with a
large zero offset, the pH may not be close
to 7. In this case, standardize the controller
at 7. (Section 3.4).
6. If the controller does not read correctly (after
standardizing, if necessary), replace the con-
troller.
7. If a millivolt source is available, it can be con-
nected to TB2-7 and TB2-10 to simulate pH val-
ues.
Refer to Figure 8-1 for the relationship
between mV and pH, sample values are +172
mV for 4 pH and -172 mV for 10 pH.
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