Kikusui PAD-L III Series, Operation Manual

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4-6 Applied Operation PAD-L
4.2.2 Output voltage control (II) with external resistor
• This voltage control is a fail-safe system in which no overshoot occurs when
switching a resistance value.
• The output voltage Eo and resistance value R2 are inversely proportional, as
shown in Fig. 4-4. If the circuit opens when switching the resistor or due to an
accident, the resistance value become
∞
(infinite) and output becomes zero.
• The output voltage Eo is determined by R2 and Eref, according to the equation
shown in Fig. 4-5. Eref is set with the VOLTAGE setting knob on the front
panel. (Use a guard cap (supplied) to disable a setting knob on the panel.)
• The advantage of this applied operation is a fail-safe system in which the output
voltage decreases if the circuit becomes open. The drawback is that it is
impractical when a low voltage is programmed, since a very high resistance
value is required. In real-world applications, 0 to 200 k
Ω
variable resistors are
suitable. (In general, high resistance requires greater attention to temperature
coefficient and noise.)
Eo max
0V
0
Ω
Eo
∞
Resistance value R2
Control (II) with external resistor
Control (I) with e
xternal resistor
Output v
oltage Eo
Set with the knob
on the panel
Fig. 4-4 Control (I) and control (II) with external resistor