PLZ-4WL
121
Operating Area
App.
If the protection action is set to LIMIT, the PLZ- 4W sinks current as a constant-power load at
point B. Even if you attempt to decrease the resistance to increase the current, the current
will not increase beyond point B. If you increase the resistance to decrease the input current,
overpower protection (OPP) is cleared. The PLZ-4WL returns to constant resistance (CR)
mode, and the operating point moves along segment AB.
Transition of the operating point: overcurrent protection (OCP)
If the overcurrent protection (OCP) setting I
OCP
is less than the current value IB at point B,
when the PLZ-4WL resistance is decreased (R
1
R
2
R
F
) so that the input current (load
current) increases, with the voltage of the constant-voltage power supply at V1, the operating
point moves along segment AF (A
1
A
2
F). When point F is reached, overcurrent protection
(OCP) is activated.
At this point, one of two types of operations occurs, depending on the protection action
setting for OCP. If the protection action is set to LOAD OFF, the load turns off.
If the protection action is set to LIMIT, the PLZ- 4W sinks current as a constant-current load at
point F. Even if you attempt to decrease the resistance to increase the current, the current will
not increase beyond point F. If you increase the resistance to decrease the input current,
overcurrent protection (OCP) is cleared. The PLZ-4WL returns to constant resistance (CR)
mode, and the operating point moves along segment AF.
Point B
LOAD OFF
The load is turned off (no current flows).
The PLZ-4WL stops operating as a load.
LIMIT
The PLZ-4WL switches out of constant resistance (CR) mode.
Overpower protection (OPP) continues, and the PLZ-4WL
operates as a constant-power load.
Input current [A]
Input voltage [V]
Logarithmic scale
V1
A
B
Operating area
OCP activation point
Constant resistance line
I
B
I
OCP
A
1
A
2
R
1
R
2
R
F
F
Constant current line
(OCP setting)
(constant resistance settings: R
1
, R
2
, and R
F
)
Point F
LOAD OFF
The load is turned off (no current flows).
The PLZ-4WL stops operating as a load.
LIMIT
The PLZ-4WL switches out of constant resistance (CR) mode.
Overcurrent protection (OCP) continues, and the PLZ-4WL
operates as a constant-current load.