System Startup Errors - Omron OMNUC U Series Technical Manual

Connection to Position Control Unit
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System Startup Errors

The Position Control Unit may malfunction due to incorrect wiring, setting, or sequence
when power is supplied to the Position Control Unit or while the Position Control Unit is
operating. Probable causes of system startup errors and countermeasures are de-
scribed below.
System Does Not Start
· The 3G2A5-NC111-EV1 in operation may not detect the startup signal, especially when the Unit is
mounted to the following:
· CV-series Backplane
· Slave Rack
Probable cause
The 3G2A5-NC111-EV1 could not
detect the startup signal because
the startup signal is ON for too
short a time.
Note 1. The program cycle time of the CV-series PC is shorter than that of the C-series PC. The
3G2A5-NC111-EV1, therefore, may not detect the startup signal correctly if the startup signal
is ON for too short a time.
Note 2. The remote communications cycle time is different in timing from the program cycle time. The
startup signal, therefore, may not be detected in remote communications if the startup signal
is ON for too short a time.
Communications Errors Result
· The 3G2A5-NC111-EV1 Unit in operation may cause positioning data communications errors or may have
difficulty in reading data correctly, especially when the Unit is mounted to the following:
· CV-series Backplane
· Slave Rack
Probable cause
The communications cycle time
clock data is not being transmitted
to the 3G2A5-NC111-EV1
correctly.
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Item to check
· The startup signal is ON for a
single cycle time.
Item to check
· The communications cycle time
clock timing is shorter than the
remote communications cycle
time.
· The CV's cycle time clock does
not suit the 3G2A5-NC111-EV1.
Chapter 2
Countermeasure
· Extend the period in which the
startup signal is ON so that the
3G2A5-NC111-EV1 can detect
the startup signal.
Countermeasure
· Extend the cycle time clock's ON
timing so that the
3G2A5-NC111-EV1 can detect
the communications cycle time
clock data.
· Create a clock by using the re-
turn signal from the Slave.