Troubleshooting By Symptom; When The Count Operation Does Not Start; When The Count Operation Is Not Normal - Mitsubishi Electric RD62P2E Application User's Manual

3.3

Troubleshooting by Symptom

When the count operation does not start

Check item
Check whether the CPU module indicates any error.
Apply a voltage directly to the pulse input terminals of A and B, and check
that each LED of A and B turns on.
Check whether the external wiring of A and B is normal.
Check whether CH1 Count enable command (Y4) is on.
Check whether the pulse input method is the same as the pulse input mode of
Basic setting.
Check whether the counter operation mode is set to pulse count mode.
Check whether CH1 Counter function selection start command (Y6) is on, and
a voltage is applied to the function start input terminals.
Check whether an overflow error occurs.

When the count operation is not normal

Check item
Check whether the external wiring of A and B is normal.
Check whether the maximum counting speed for input pulses falls within the
range of the counting speed of Basic setting.
Check whether the waveform of pulses being inputted meets the performance
specifications.
Check whether the count value data is processed as 32-bit signed binary data
in the program.
Check whether the shielded twisted pair cables are used for pulse input
wiring.
Check whether any noise comes from the grounded part of the high-speed
counter module.
Check whether measures against noise are taken for the adjacent devices
and inside the control panel.
Check whether the distance between the high voltage device and pulse input
line is kept enough.
Check whether both CH1 and CH2 return the same count value after the
same count is inputted.
Check whether the preset value is set so that the value is out of the count
range of the ring counter (ring counter function only).
3 TROUBLESHOOTING
48
3.3 Troubleshooting by Symptom
Action
If the CPU module indicates an error, refer to the troubleshooting in the
following manual.
 MELSEC iQ-R CPU Module User's Manual (Application)
If the LEDs turn on, check the external wiring and wiring on the encoder side
to correct the errors. If the LEDs do not turn on, a hardware failure is a likely
cause. Please consult your local Mitsubishi representative.
Check the external wiring to correct the errors.
Turn on CH1 Count enable command (Y4) using a program.
Match the pulse input method to the pulse input mode of Basic setting.
Set the counter operation mode to pulse count mode in Basic setting.
If the count disable function is set by the counter function selection, turn off
CH1 Counter function selection start command (Y6) and the function start
input terminals.
Execute a preset to clear the overflow error.
For details, refer to the following.
Page 47 Checking Module Status
Action
Check the external wiring to correct the errors.
Even in 1-phase input, connecting an ABCOM terminal to a pulse signal can
result in an incorrect count. Reconnect the ABCOM terminal again to an
external power supply (5V/12V/24V) or a GND terminal. ( MELSEC iQ-R
High-Speed Counter Module User's Manual (Startup))
Correct the counting speed setting of Basic setting to accommodate the
maximum counting speed for input pulses.
Observe and check the pulse waveform with a synchroscope. If the input
pulse does not meet the performance specifications, input pulses which meet
the performance specifications.
Correct the program to process the count value data in 32-bit signed binary.
Use the shielded twisted pair cables for pulse input wiring.
Separate the grounding cable of the high-speed counter module from the
grounded part. If the high-speed counter module touches the grounded part,
separate it.
Take noise reduction measures such as attaching a CR surge suppressor to
the magnet switch.
Bundle the pulse input lines separately from other lines in piping and tubing,
and keep a distance of 150mm or more between the pulse input lines and the
power line even inside the control panel.
If these count values are different each other, a hardware failure is a likely
cause. Please consult your local Mitsubishi representative.
Set the preset value so that the value falls within the count range of the ring
counter.