Instruction manual

MODEL XMT-A-FF/FI SECTION 15.0

TROUBLESHOOTING

15.2 TROUBLESHOOTING WHEN A FAULT OR WARNING MESSAGE IS SHOWING

Fault message Explanation See Section

RTD Open RTD measuring circuit is open 15.2.1

RTD W Overrange RTD resistance is outside the range for Pt 100 or 22kNTC 15.2.1

Broken pH Glass pH sensing element in pH sensor is broken 15.2.2

pH Glass Z High pH glass impedance exceeds programmed level 15.2.2

ADC Read Error Analog to digital converter failed 15.2.3

Warning message Explanation See Section

PV > DisplayLimit Process variable value exceeds display limit 15.2.4

Sensor Curr High Sensor input current exceed 210 uA 15.2.4

Sensor Curr Low Sensor input current is a large negative number 15.2.4

Need Zero Cal Sensor needs re-zeroing. Concentration reading is too negative. 15.2.5

pH mV Too High mV signal from pH sensor is too big 15.2.6

No pH Soln GND Solution ground terminal is not connected 15.2.7

Temperature High Temperature reading exceeds 150°C 15.2.1

Temperature Low Temperature reading is less than -15°C 15.2.1

Sense Line Open RTD sense line is not connected 15.2.8

Need Factory Cal Transmitter needs factory calibration 15.2.9

Ground >10% Off Bad ground 15.2.10

EE Buffer Overflow EEPROM buffer overflow 15.2.11

EE Chksum Error EEPROM checksum error 15.2.12

EE Write Error EEPROM write error 15.2.13

Sense Line Open Sense line is not connected 15.2.14

15.2.1 RTD Open, RTD Ω Overrange, Temperature High, Temperature Low

These messages usually mean that the RTD (or thermistor in the case of the HX438 and GX448 sensors) is open or short-

ed or there is an open or short in the connecting wiring.

1. Verify all wiring connections, including wiring in a junction box, if one is being used.

2. Disconnect the RTD IN, RTD SENSE, and RTD RETURN leads or the thermistor leads at the transmitter. Be sure to

note the color of the wire and where it was attached. Measure the resistance between the RTD IN and RETURN leads.

For a thermistor, measure the resistance between the two leads. The resistance should be close to the value in the

table in Section 15.14.2. If the temperature element is open (infinite resistance) or shorted (very low resistance),

replace the sensor. In the meantime, use manual temperature compensation.

3. For oxygen measurements using the HX438 and GX448 sensors, or other steam-sterilizable sensor using a 22kNTC,

the Temperature High error will appear if the transmitter was not properly configured. See Section 7.4.