Watlow Series 935B - Manual (Page 39)

Watlow Series 935B User’s Manual 39
Table 13 - Possible Displayed Error Codes and Actions
To Troubleshoot Sensor
• Remove sensor wires from Terminals 1 and 2.
• For a thermocouple sensor Series 935B, place a jumper wire on Terminals 1 and 2. Control should display the ambient
temperature at the back of the control.
• For an RTD sensor Series 935B, place a 110 +/- 10 Ω resistor on Terminals 1 and 2. The control should read 100Ω = 32°F,
110 Ω = 77°F, 120Ω = 127°F.
• An RTD sensor Series 935B can be configured in software as if it were a
thermocouple unit, and then tested as above.
• You can restore factory calibration [`rST] , see p. 36-37.
Table 14 - Troubleshoot Control Outputs
When indications such as significant differences between set point and
actual temperatures point to no output action, check output configurations
as described on p. 23. Check wiring, p. 44.
Measure
Output Terminals Load-on State Load-off State
“C” Output 1 3 & 4 LED 1 on LED 1 off
3.0 to 7.0VÎ (dc) 0.0VÎ (dc)
“C” Output 2 5 & 6 LED 2 on LED 2 off
3.0 to 7.0VÎ (dc) 0.0VÎ (dc)
Control is inoperable. Check for line voltage at
terminals 7 and 8. [````
Electrical noise. Cycle power to system. See if error clears.
Check system for electrical interference. [`Er5]
Open Thermocouple, bad Check the sensor, A-D
connection, or broken wire. replace as necessary.
[`Er4]
Sensor type Go to In prompt, Sensor
mismatch. check selection (see p. 22). over range
[`Er3]
Sensor type Go to In prompt, check selection (see p. 22), Sensor
mismatch or open RTD. or check RTD, replace as necessary. under range
[`Er2]
Reversed thermocouple Change the sensor A-D
connection + to –. leads on Terminals 1 and 2. under flow
[`Er1]
Display Probable Cause Recommended Action