PLZ-U Basic Operation 4-9
4.4 Protection Functions and Alarms
When a protection function trips and an alarm is activated, the ALM indicator of the
corresponding channel illuminates. At the same time, ALARM STATUS (pin 16) of
FRAME CONT connector 1 on the rear panel turns on (open collector output).
There are two types of protection functions: those that allow you to set the trip point
and those with a fixed trip point. In addition, for the OCP and the OPP, you can
specify whether to turn off or limit the load when such conditions are detected.
• For the operation of the protection function in each operation mode, see appen-
dix A.2, “Basic Operation Modes.”
4.4.1 Protection Function
■ Undervoltage protection (UVP)
The protection trips when the voltage falls below the specified voltage when the
load is turned on. At this point, the load is turned off. The undervoltage protection
can be disabled (OFF).
• For a description of setting the undervoltage value, see section 4.4.3, “Setting
the Trip Points.”
■ Overcurrent protection (OCP)
Overcurrent is detected on the smaller of the two values, the specified overcurrent
value or 110 % of the rated current of each range. The overcurrent value can be set
in the range of 0 % to 110 % of the rated current of the H range.
Through configuration, you can select whether to turn off the load or limit the cur-
rent when the protection trips. When current limit is selected, the alarm is cleared
when the current falls below the trip point.
• For a description of setting the overcurrent value, see section 4.4.3, “Setting the
Trip Points.”
• For a description of configuration settings, see section 5.9, “Configuration Set-
tings.”
■ Overpower protection (OPP)
Overpower is detected on the smaller of the two values, the specified overpower
value or 110 % of the rated power of each range. The overpower value can be set in
the range of 0 % to 110 % of the rated power of the H range.
Through configuration, you can select whether to turn off the load or limit the power
when the protection trips. When power limit is selected, the alarm is cleared when
the voltage falls below the trip point.
• For a description of setting the overpower value, see section 4.4.3, “Setting the
Trip Points.”
• For a description of configuration settings, see section 5.9, “Configuration Set-
tings.”
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