Kikusui PLZ-3WH Series, Operation Manual

Page: 92 / 172

4-52
Chapter 4: Operating Procedure
(b) External resistance method
The external resistance from 0 Ω to approx. 10 k Ω is connected to the load unit to change the resistance in reverse
proportion to the external resistance.
Fig. 4.6-6
● ●
● ●
● Setup procedure
(1) Check that the [LOAD] switch is turned off, and set the RSET value to the minimum resistance on the front panel.
(2) Press the [POWER] switch to turn off the load unit.
(3) Connect the external variable resistor to J2 terminals 11 and 12 on the rear panel, and maximize the resistance.
(4) On the rear panel, set the setup switch [SW2] to the “LOCAL” position and [SW3] to the “R” position.
(5) Press the [POWER] switch to turn on the load unit.
(6) Press the [R SET] key on the front panel to enable the CR mode.
(7) Using the [SHIFT] + [STOP] (KEYLOCK) keys, put the load unit into keylock condition.
The external variable resistor used should be resistant to temperatures and aging, and its residual resistance should not
exceed 300 Ω . We recommend use of a wire wound resistor, metal film resistor, or multirotational potentiometer. To
prevent noise interference, use twisted pair or shielded signal cable.
If the RSET value is set to any value other than the minimum resistance, the working resistance range fails to cover the
standard value. If the RSET value is set to the maximum resistance, control with external resistance becomes
impossible and the working resistance is minimized.
When the external voltage is used for external control, even the CR mode needs the same terminals as the CC mode.
Therefore, always recheck the operating mode.
When Rin is equal to 10 k Ω , Io is securely 0 A. This may cause a minor offset as shown in the figure below.
11
12
Equivalent circuit
J2
Rin
Approx. 1mA
MAX16V
Ro ≒ × Rmin
10k
10k
×
Rin
：
External variable resistor
0 ≦ Rin ≦ Approx.10(k Ω )
： Working resistance
： Minimum resistance of CR mode
： Input current
： Rated voltage
Io
≒
Eo(10k × Rin)
10k × Rmin
Rin
Ro
Rmin
Io
Eo
Fig. 4.6-7
Io
Input
Current
0A
Rin
0 Ω 5k Ω 10k Ω
Rmin
Rmax
Rin
Rmax
Rmin
Io ： External variable resistor
： Maximum resistance of CR mode
： Minimum resistance of CR mode
： Rated current
Logical input current
Actual input current
: Input current