NMC-64 Irrigation
Problems and trouble shooting:
# Problem description Troubleshooting
1
Relays are not working, there are no sensor
readings, and there is no communication with
the hardware.
Check led blinking. If the led on the output
cards aren’t blinking, then the problem is
probably that the I2C bus is pulled down by
one of the cards.
Disconnect the output cards and digital
input cards one by one and check whether
the LED’s of the remaining cards starts
blinking or the sensor’s readings are
correct.
If you can’t find the faulty card it is probable
that the CPU card is faulty, contact the
Netafim dealer closest to you.
2
One of the output cards isn’t working at all.
(LED is switched off)
The reason for this problem is probably a
short circuit in one of the relay coils. The
short activates a thermal fuse on the power
supply card.
Replace the relay card.
3
Alarm messages:
Temp Sensor Shorted.
Temp Sensor Opened.
Temp Sensor User Err.
Out Temp Sen. Shorted
Out Temp Sen. Opened
Out Temp Sen. Fail
The reason for these problems could be
that one of the sensors is shorted or
disconnected.
Check the alarm messages to see sensor’s
number and failure description; “Opened”
or “Shorted”.
Connect Ohmmeter between the black and
red wires of the temperature sensor and
check if there is 30 kOhm. There are
variations in the readings of the ohmmeter
according to temperature. If the temperature
is higher then 25°C the resistance will
decrease and if the temperature is lower
then 25°C the resistance will increase.
For example:
37.5 kOhm - in 20°C
24.1 kOhm - in 30°C
78
To Next Page
Loading...
Need help?
General
