Troubleshooting For Digital Input Modules; Checking With Leds; Troubleshooting By Symptom - Mitsubishi Electric NZ2FTGN User Manual

14.8

Troubleshooting for Digital Input Modules

If problems occur on the digital input module, perform the following.

Checking with LEDs

When the module status LED turns on in red
Check the following items in order from the top.
Item
Is the external power supply (24VDC) wired?
Is the external power supply (24VDC) turned on?
Is the voltage of the external power supply (24VDC)
within the specified range?
Is the I/O module mounted properly?
If the problem persists after checking the above, acquire the service file, and please consult your local Mitsubishi
representative. ( Page 88 Acquisition of the service file)
The LED status can also be checked on the Web server. ( Page 70 "Overview")

Troubleshooting by symptom

ON/OFF status of an external input cannot be input
Check the following items in order from the top.
Item
When the external input device turns on and off, does the corresponding LED of
the input module turn on and off?
Check the channel status LED of the actual digital input module, not the Web
server. When the input power supply voltage is lowered, the indication of both
channel status LEDs may not match.
Is the parameter "Input delay" set correctly? (Except for the NZ2FTS1-16DE,
NZ2FTS1-16D, and NZ2FTS2-4A)
■For the NZ2FT2-4A
Do stepped distortions occur near the zero cross voltage of the input signal
(AC)?
■For the NZ2FT2-4A
Is a 4A slow fuse being used?
■For the NZ2FT2-4A
Is the 4A slow fuse blown?
■For the NZ2FT2-4A
Is the current value 4A or less?
■For the NZ2FT2-4A
Are high-frequency input signals (AC) above 65Hz being used?
If the ON/OFF status of the external input still cannot be input after checking all of the above and checking the LED of the
coupler, Web server, and so on, there is a risk of a hardware failure in the digital input module.
Acquire the service files, and please consult your local Mitsubishi representative. ( Page 88 Acquisition of the service file)
Action
Wire the external power supply (24VDC).
Turn on the external power supply (24VDC).
Set the voltage of the external power supply within the range of performance specifications.
Mount the I/O module again by pressing it to the coupler until it clicks.
Action
If the input power supply LED 3.1 is off, there is a problem with the input
wiring. Check that the input wiring is not disconnected or short-circuited and
that the voltage of the input signal is correct. Then, change the wiring if
necessary.
When the parameter "Input delay" is set, the input signal changes after the
Input delay time passes following a change on the external device.
Disable Input delay or check the setting of Input delay.
If so, improve the waveform of the input signal by means such as by using
an on-line type UPS.
Install a 4A slow fuse.
If so, replace the 4A slow fuse.
Set the current value to 4A or less.
Set the frequency of the input signal to 65Hz or less.
14 DIGITAL INPUT MODULE
14.8 Troubleshooting for Digital Input Modules
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