PLZ-4WL
49
3
Ad
vanced Operat
ions
Protection Functions
The protection functions can be used to automatically turn off the load or limit the current to
prevent the PLZ-4WL’s internal circuitry from being damaged and to protect the DUT.
An alarm occurs when the protection functions are activated. When an alarm occurs, the load
turns off (or the current is limited), and the ALARM STATUS pin (pin 20) of the J1 connector
on the rear panel turns on (open-collector output from a photocoupler).
When the load turns off, a popup window appears on the screen.
Example of the display when UVP is activated
Protection function types
The types of protection functions and what they do are listed below. How the protection
functions operate in different operation modes is explained in the appendix.
0.00
mA
0.000
V
0.000
W
CC
0.000
A
SET
H 50A
30V
ALARM
ENTER
SLE
W
RATE
2.500 A/μs
UVP
0:20:03
See
Protection Function
Protection-Function-Activation Value
Protection-Function
Action
Overcurrent
protection (OCP)
A specified current value (overcurrent-protection-
activation value) or 110 % of the maximum current
range value
Load off or limit
1
1
If you choose to limit the current, the current is limited so that the protection-function-activation
value is not exceeded. Current limiting stops after the alarm is released.
Overvoltage
protection (OVP)
115 % of the maximum input voltage
Load off
Overpower protection
(OPP)
A specified power value (overpower-protection-
activation value) or 110 % of the maximum power
Load off or limit
1
Undervoltage
protection (UVP)
2
2
UVP can be disabled.
A specified minimum voltage value (undervoltage-
protection-activation value)
Load off
Reverse-connection
protection (REV)
3
3
When a reverse voltage is detected, turn off the DUT immediately.
A reverse voltage at the load input terminals
Load off
Overheat protection
(OHP)
4
4
If OHP is activated, check to make sure that the front panel inlet and the rear panel outlet are not
blocked.
An internal power unit temperature that exceeds
the defined limit
Load off
Alarm input
protection
5
5
Release the alarm of the PLZ-4WL after you release the alarm of the device connected to external
control.
An L level (CMOS) signal received by the ALARM
INPUT pin (pin 12) of the J1 connector
Load off