"PTC" TYPE TEMPERATURE SENSORS
The PTCs can be compared to bimetallic thermostats where the contact opens and closes at the approximate temperature,
defined as their operating characteristic (NAT=operating temperature).
The sensor is calibrated for one temperature only that can vary from 60°C to 190°C, in 10°C (In relation to the acquired
probe), in 10°C steps (60-70-80-90-100-110-120-130-140-145-150-155-160-170-180-190).
The PTCs are electronic thermometric sensors made with a chemical mixture that vary their electrical resistance according
to the recorded temperature.
There is a NAT (operating temperature) for the PTCs as well as for the bimetallic thermostats.
The PTCs do not allow precision adjustments since the characteristic resistance values are fixed at –5°C and +5°K of
NAT.
The PTC characteristic resistance values are set by the DIN 44081 and 44082 standards.
Since the PTC resistance curve is very rapid, in the section between NAT -5°C andNAT +5°K, it is quite difficult to make
adjustments in a temperature span of less than +/- 5°K.
one of the PTCs is short-circuited
the FLT yellow LED and the corresponding LED
(ALL1-ALL2-FAN) are flashing
replace or repair the PTC
ATTENTION
If the right model of PTC is not connected to the T119 control unit, the LEDs flash.
The PTC temperature is nat + T = 1300 ohm.
This new function allows enabling or disabling the PTC diagnostic device (Foc and Fcc):
Diagnostics disabling method:
power the instrument keeping the TEST button pressed until the FAULT LED comes ON
With the diagnostics disabled, the FAULT yellow LED will be ON all the time.
Diagnostics re-enabling method
Power the instrument keeping the TEST button pressed until all LEDs go OFF. With the diagnostics enabled, the FAULT
yellow LED will be OFF and flash in case of sensor faults.
The T119 control units will be supplied with the sensor diagnostics ENABLED.
PTC SENSOR FAULT DIAGNOSIS
If one of the PTCs is short-circuited or interrupted, you have the following indications:
alarm PTC ALL1(L1) the FAULT + ALL1 LED is flashing
TRIP PTC ALL2(L2) the FAULT + ALL2 LED is flashing
FAN PTC FAN the FAULT +FAN LED is flashing
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