Toshiba T2N - Manual (Page 97)

6.Troubleshooting
82 PROSEC T2N
When a problem with the T2N system occurs as one of the following
phenomena, external factors should be suspected.
(1) When the problem occurs in synchronisation with the operation of
input/output equipment
In this case, there is a possibility that the cause is noise generated when
the output equipment switches ON/OFF. Apply the noise counter-
measures described in Section 3 Application Precautions for I/O Modules.
(2) When the problem occurs in synchronisation with the operation of peripheral
power equipment and high-frequency equipment
In this case, the effect of noise induced in the input/output signal lines may
be suspected. Also, depending on the power supply system and the
grounding system, the cause may sometimes be surges or voltage
fluctuations in the power supply and fluctuations in the ground potential.
Check with the Notes described in Section 4 Installation and Wiring.
Depending on the case, one method is to try the effect of disconnecting the
ground.
(3) When the problem occurs in synchronisation with the operation of
machinery, the effect of vibration may be considered. Check the state of
installation of units/modules and, at the same time, study vibration
countermeasures, such as the use of vibration-proofing rubber.
(4) When similar problems re-occur even after replacing faulty modules,
thoroughly check that there is no risk of entry of metal particles or drops of
water.
Apart from the above causes, if, for instance, the ambient temperature exceeds
the specified range, stable operation of the system cannot be guaranteed. Take
thorough precautions over the environmental conditions.
6.7
Faults Due to External
Problems