Emerson Rosemount5081, Instruction Manual, Page: 108 / 152

A large standardization offset may be caused by a poisoned reference electrode. Poisoning
agents can cause the pH to be offset by as much as two pH units. To check the reference
voltage, see
Section 8.4.13 .
AdC
AdC means the analog to digital converter has failed.
1.
Verify that the sensor wiring is correct and connections are tight. Be sure to check
connections at the junction box if one is being used.
2. Disconnect sensor(s) and simulate temperature and sensor input.
To simulate See Section
Dissolved oxy-
gen Section 8.4.9
Ozone or chlor-
ine Section 8.4.10
pH Section 8.4.11
Temperature Section 8.4.12
If the transmitter does not respond to simulated signals, the analog PCB has
probably failed.
3. Call the factory for assistance.
bAd Gnd
bAd Gnd usually means a problem with the analog PCB. Contact the factory.
In too biG
In too biG means the raw millivolt signal from the pH sensor is too large.
1.
Verify that sensor wiring is correct and connections are tight. Be sure to check
connections at the junction box if one is being used.
2. Replace the pH sensor with a sensor known to be working.
3. If replacing the pH sensor does not cause the message to disappear, call the factory
for assistance.
RitE Err
Program settings in the 5081-A can be protected against accidental changes by setting a
three-digit security code. Settings can be further protected by removing a jumper (JP-1)
from the CPU board. If JP-1 has been removed, program settings cannot be changed.
Diagnostics and troubleshooting
98 Rosemount 5081