172
Temperature Sensing Errors Section 8-3
8-3 Temperature Sensing Errors
Temperature Sensing Not Possible or Abnormal
Probable cause Remedy
Connections Polarity or wiring of a temperature sensor is incor-
rect.
Correct the wiring of the temperature sensor.
Temperature sensor is not an applicable one. Replace the temperature sensor with an applica-
ble one.
Leads of a temperature sensor are disconnected,
short-circuited, or deteriorated.
Replace the temperature sensor.
Temperature sensors are not used. Use temperature sensors.
Thermocouple does not use applicable compen-
sating conductors.
• Replace the thermocouple with another ther-
mocouple with long leads.
• Connect applicable compensating conductors
for the thermocouple.
Thermocouple is connected to the E5ZN with a
device using a metal that is different in type from
the metal of the thermocouple or that of the com-
pensating conductors.
Connect a thermocouple-dedicated device
between the thermocouple and the E5ZN.
A screw of the terminal block of the E5ZN is loos-
ened and improper contact is resulting.
Tighten the screw.
Leads or compensating conductors of a thermo-
couple are too long and leads or compensating
conductors have resistance.
• Use sufficiently thick compensating conduc-
tors.
• Change the location of the thermocouple so
that the length of the leads or compensating
conductors can be shortened.
The resistance of the conductors for the 3 termi-
nals is different from the resistance of the temper-
ature sensor connected to the E5ZN.
Use conductors that are the same in resistance
for the two B terminals and the A terminal.
Installation Noise is affecting the E5ZN. • Separate the E5ZN from the source of the
noise.
• Connect a surge absorber or noise filter to the
device generating the noise.
Inductive noise generated from power lines is
affecting the leads of a temperature sensor.
• Separate the leads from the power lines.
• Wire the leads in a separate conduit or duct.
• Do not wire the leads alongside power lines.
• Shorten the leads.
• Shield the leads.
Thermal response of a temperature sensor con-
nected to the E5ZN is slow because the tempera-
ture sensor is located far from the temperature
controlling position of the E5ZN.
Locate the tip of the protective tubing of the tem-
perature sensor at the temperature controlling
position.
Ambient operating temperature of the E5ZN is not
within the allowable ambient operating tempera-
ture range of the E5ZN.
The ambient operating temperature range of the
E5ZN must be between -10 and 55°C.
Ambient operating temperature of the E5ZN is not
within the allowable ambient operating tempera-
ture range of the E5ZN.
Shield the E5ZN.
E5ZN is affected by heat radiation from Peripheral
Devices and the temperature of the terminal block
of the E5ZN is not even.
Install the E5ZN in a location where it will not be
affected by heat radiation.
Terminal block of the E5ZN is affected by wind. Protect the terminal block of the E5ZN against
wind.
To Next Page
Loading...
