Toshiba Tosvert VF-AS1 Instruction Manual page 153

 Differential (D) gain
The differential (D) gain set with  is the differential (D) gain obtained by PID control.
The differential gain increases the speed of response to rapid changes in deviation. If this gain is set excessively
high, a phenomenon in which the output frequency greatly fluctuates may occur.
Previous deviation-current deviation
Feedback value
If one of input terminals is assigned input terminal function 52/53 (PID differentiation/integration reset), differential
and integral values are always 0 (zero) during the input terminal on.
5) Adjusting the analog command voltage and current
For items which can be adjusted by reference and feedback input, such as voltage/current input (VI/II input),voltage
input (RR/S4 input) and voltage input (RX input), adjust scaling factor of the voltage/current if necessary.
When feedback signals are very low, the gain can be increased by this adjustment.
When VI/II used as a voltage input terminal
(Default setting)
aif2
(80Hz)
f202
(0Hz) 2V
f201
20%
When RR/S4 used as a voltage input terminal
(Default setting)
avf2
(80Hz)
f211
(0Hz) 0V
f210
0%
High differential gain
When VI/II used as a current input terminal
(f108 needs to be set to 1)
aif2
(80Hz)
f202
10V (0Hz)
f203 f201
100%
When RX used as a voltage input terminal
(Default setting)
f219
(80Hz)
f217
10V (0Hz) 0V
f212 f216
100% 0%
F-37
Low differential gain
4mA 20mA
f203
20% 100%
E6581442
Time
6
10V
f218
100%