Specifications
48
MODEL 30 pH/DO SECTION 8.0
TROUBLESHOOTING
SECTION 8.0
TROUBLESHOOTING
8.1 OVERVIEW
8.2 TROUBLESHOOTING USING FAULT CODES
8.3 TROUBLESHOOTING WHEN NO ERROR MESSAGE IS SHOWING — DO
8.4 TROUBLESHOOTING WHEN NO ERROR MESSAGE IS SHOWING — pH
8.5 TROUBLESHOOTING WHEN NO ERROR MESSAGE IS SHOWING — GENERAL
8.6 SIMULATING INPUTS — pH
8.7 SIMULATING TEMPERATURE
8.8 MEASURING REFERENCE VOLTAGE — pH
8.1 OVERVIEW
The Model 30 continuously monitors itself and the sensor for faults. When the transmitter detects a fault, the
word
fault
appears in the display alternately with the measurement. If alarm 3 was configured as a fault alarm,
the alarm relay will energize. The outputs do not change during a fault condition. They continue to reflect the
measured dissolved oxygen, pH, ORP, or temperature. Press
""
to display the fault codes.
8.2 TROUBLESHOOTING USING FAULT CODES
8.2.1 Sensor Current Exceeded
Excessive sensor current implies that the sensor is miswired or the sensor has failed.
8.2.2 Absolute Value of Measured Voltage Exceeds 2500 mV
The voltage of a pH cell is usually between 600 mV and -600 mV, and the voltage of an ORP cell is between 2000
and -2000 mV. Readings outside the range -2500 mV to 2500 mV usually indicate a problem with sensor wiring or
analyzer electronics.
A. If the sensor is being installed for the first time, check the wiring connections. See Section 3.2. If a junction box
is being used, check connections at the junction box, too.
B. If the preamplifier is in a junction box, verify that the wires supplying the power (±5 Vdc) to the preamplifier are
connected at the analyzer and junction box.
C. Verify that the sensor is completely submerged in the process liquid.
Fault Code Explanation See Section
S1 Out of Range Sensor current exceeded (dissolved oxygen only) 8.2.1
S2 Out of Range Absolute value of measured voltage exceeds 2500 mV (pH/ORP only) 8.2.2
S2 Broken Glass pH sensitive glass membrane is broken 8.2.3
TC1 Open or TC2 Open RTD for sensor 1 or sensor 2 is open 8.2.4
TC1 Shorted or TC2 Shorted RTD for sensor 1 or sensor 2 is shorted 8.2.4
S1 or S2 Sense Line Open RTD sense line for sensor 1 or sensor 2 is open 8.2.5
EEPROM Failure EEPROM failure 8.2.6