Toshiba nv Series Instruction Manual page 89

■ External cause check
If a controller abnormality occurs as one of the following symptoms, it may be due to an
external cause:
・ If the failure occurs in synchronization with operation of I/O equipment:
The failure may be due to noise that occurs when the output equipment is turned ON
and OFF. Take measures against noise according to the caution for application of I/O
modules.
・ If the failure occurs in synchronization with operation of peripheral motor or
high-frequency equipment:
The failure may be due to influence of noise induced through the I/O signal line.
Alternatively, it may be due to power supply surge or fluctuation in voltage or ground
potential, depending on the ground system. Read the precautions described in the
installation/wiring, section in this manual, again. One of the suggested methods is to
continue operation with the ground line removed in some cases.
・ If the abnormality occurs in synchronization with operation of the machine:
The abnormality might be due to influence of vibration. Check the unit and module
installation conditions. Also, consider vibration-proof measures such as use of
vibration-proof rubber.
・ If a similar trouble recurs after replacement of the troubled module:
Thoroughly check whether the module contains scrap metal or a water droplet that
may drop. In addition to the above cases, stable operation of the system will not be
guaranteed if the ambient temperature is outside the range required in the
specification. Pay special attention also to the environmental conditions.
Unified Controller nv series type2 light Controller Unit Instruction Manual
7.1 If a Trouble is Suspected
71