Omron Sysmac CJ Series, Operation Manual

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Troubleshooting Section 5-2
5-2-1 Troubleshooting from Symptoms: Measurement Errors
Incorrect Measurement or No Measurement
Step Possible Cause Remedy
Connection The temperature sensor is connected to the wrong
terminals or polarity is reversed. Wire temperature sensor correctly.
The temperature sensor connected to the Temper-
ature Control Unit is not compatible with the Unit. Replace the temperature sensor with one that is com-
patible with the Temperature Control Unit.
The temperature sensor wires are broken, short-
circuited, or damaged. Replace the temperature sensor with a good one.
No temperature sensor is connected. Connect a temperature sensor.
The compensating conductor being used is not
compatible with the thermocouple. • Directly connect a thermocouple with long lead wires.
• Use a compensating conductor that is compatible
with the thermocouple.
Some equipment is connected between the ther-
mocouple and Temperature Control Unit that uses
metal different than the metal in the compensating
conductor or thermocouple. The equipment used for connections must be made
specifically for use with thermocouples.
The terminal screws are loose so there is poor
contact between the wires and terminals. Tighten the terminal screws.
The thermocouple’s lead wires or the compensat-
ing conductors are too long, so the resistance in
the wires is affecting operation. • Use thicker compensating conductors.
• Change the wiring location to reduce the length of the
wiring.
The conductors between the temperature sensor
and the Temperature Control Unit’s terminals
have three different conductive resistances. Use conductors with the same resistance for the A, B,
and B’ terminals.
Installation Noise from electric equipment around the Temper-
ature Control Unit is affecting operation. • Move the Temperature Control Unit away from the
equipment that is generating the noise.
• Install surge protectors or noise filters on the equip-
ment that is generating the noise.
The temperature sensor’s leads run close to
power lines, so noise is being induced from the
power lines. • Separate the temperature sensor’s leads from the
power lines.
• Run the temperature sensor’s leads in a conduit or
duct separate from the one carrying the power lines.
• Do not run the temperature sensor’s leads parallel to
the power lines.
• Reduce the length of the temperature sensor’s leads.
• Use shielded wire for the temperature sensor’s leads.
The temperature sensor is installed too far from
the point being controlled, so the response to tem-
perature changes is delayed. Install the temperature sensor in a protective tube
closer to the point being controlled.
The ambient temperature where the Temperature
Control Unit is installed exceeds the Unit’s ratings. Install the Temperature Control Unit in a location with an
ambient temperature between 0 and 55
°
C.
Wireless equipment is being used near the Tem-
perature Control Unit. Shield the Temperature Control Unit.
The temperature around the Temperature Control
Unit is not uniform because of heat-generating
equipment near the Unit. Move the Temperature Control Unit to a location where
it won’t be affected by heat-generating equipment.
There is a draft (breeze) on the Temperature Con-
trol Unit’s terminal block. Eliminate or block the draft.
Settings The Input Type setting is incorrect. Set the Input Type correctly.
The Temperature Units setting is incorrect. Set the Temperature Units correctly.
The measured temperature appears to be shifted
because of the Input Compensation Value setting. Set the Input Compensation Value to 0.0.
The Data Format setting is incorrect. Check the Data Format set on pin 2 of the DIP switch
and correct the ladder program if necessary.
The host’s ladder program is incorrect.