User`s manual

256
8.4 Troubleshooting by Symptoms
This section describes troubleshooting methods by symptom.
In this section, I/O numbers (X/Y), buffer memory addresses, and external input terminals are those of CH1.
For I/O numbers (X/Y) of CH2, refer to the following section.
Page 32, Section 3.3.1
For buffer memory addresses of CH2, refer to the following section.
Page 42, Section 3.4.1
8.4.1 When counting (measurement) does not start, or when not
counted (measured) correctly
Check item Corrective action
Is CH1 Count enable command (Y06) on? Turn on CH1 Count enable command (Y06) by the sequence program.
When the count disable function is selected at counter
function selection, check if the function input terminal
(FUNC1) has been on.
Turn off the function input terminal (FUC1).
Is the pulse input method the same as the pulse input
mode set at the switch setting?
Set the pulse input method and the pulse input mode set at the switch setting
the same.
When reading out the present value by the sequence
program, is it read in 2 word (32bit) unit?
Read out the value in 2 word (32bit) unit.
Does the input pulse waveform meet the performance
specifications?
Check the pulse waveform with a synchronoscope. If the input pulse does not
meet the performance specifications, input pulses which meet the
performance specifications.
When the same count value is input to the other channel, is
the count result the same as that of the other channel?
If they differ, the possible cause is a failure of the module. Please consult
your local Mitsubishi representative.
Does the CPU module indicate any error?
If an error is indicated with the CPU module, please refer to the following
manual.
QCPU User's Manual (Hardware Design, Maintenance and Inspection)
Do the LEDs of A and B turn on by applying a voltage to
the pulse input terminals of A and B using such as a
voltage stabilizer?
If they turn on, check the external wiring and wiring on the encoder side. If
they do not turn on, the possible cause is a failure of the module. Please
consult your local Mitsubishi representative.
When the counter format is the ring counter, is the preset/
replace function performed out of the count range of the
ring counter?
Perform the preset/replace function within the count range of the ring counter.
Is the external wiring of A and B correct? Check the external wiring and correct errors.
Is CH1 Pulse measurement start command (function input
terminal) (Un\G1210) or CH1 Pulse measurement start
command (latch counter input terminal) (Un\G1212) set to
Measured (1
H
) depending on the terminal to be measured?
(only when the operation mode is set to the pulse
measurement mode)
Set CH1 Pulse measurement start command (function input terminal)
(Un\G1210) or CH1 Pulse measurement start command (latch counter input
terminal) (Un\G1212) to Measured (1
H
) depending on the terminal to be
measured.
Is the external wiring of the pulse measurement terminals
(FUNC1, LATCH1) correct? (only when the operation mode
is set to the pulse measurement mode)
Check the external wiring and correct errors.