Chapter 7 Usage of Various Functions
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(4) parameter setting and explanation
(a) PID8 instruction parameter setting and explanation.
Scan time
Scan time is the period of reading data (sampling), and also 10 times scaled up. The range of sampling time is
0.1 ~ 10 seconds, and actual input range is 0 ~ 100. Generally, Scan time of Digital PID control should be less
than 1/10 of time constant of system response for better performance. Time constant is the time taken the
system’s step response reaches to the 63% of steady state.
Operation mode
Select automatic or manual operating mode
Manual operate range
When manual operation is designates , manual operation value designates.(input range : 0 ~ 4000)
Output limit value
Designate minimum and maximum values of available manipulate value.(range : 0 ~ 4000)
High frequency noise removal ratio
high frequency noise removal ratio is used for derivative control operation, and shows the ratio of high
frequency noise depression. If there is a lot of high frequency noise in the control system, select the value as
higher value.
Otherwise, leave the 1. The range of parameter is 0 ~ 10 and it is not scaled up, so input the designated value
directly.(it is possible that parameter value designates ‘D’ area also)
.