Triconex Trident - Performing Routine Maintenance

Performing Routine Maintenance 165
Chapter 4 Installation and Maintenance
Performing Routine Maintenance
Routine maintenance consists of the following tasks:
• Checking the integrity of system power sources
• Periodically enabling “disabled” Output Voter Diagnostics (OVD)
• Verifying the integrity of spare modules
You should establish a schedule for routine maintenance and adhere to it to ensure
maximum safety and long service.
Checking System Power Sources
Typical installations use redundant power supplies to power the controller and the
field circuitry. Under normal operating conditions, the required power is shared
between the two power sources. Typically, the sharing is approximately equal with
each power supply providing 50 percent of the system power.
Under abnormal conditions, one of the power sources may be required to provide
100 percent of the system power. To verify the integrity of the system power
supply, you should periodically test each power source for its ability to provide
power for the entire system when the redundant source is disabled.
To verify the stability of the remaining power source under full load, every three
to six months, turn off one of the power sources and leave it off for several minutes.
After restoring power, repeat the test for the other power supply.
Ideally, this type of testing is performed with the controlled process offline; for
example, during a normally scheduled plant maintenance period. Remember to
turn on both power sources prior to restarting the controlled process.