LG MASTER-K 120S Series, Руководство пользователя, Страница: 112 / 306

Chapter 7 Usage of Various Functions
7-28
⑩
SV Ramp
If a large amount of SV changes during PID operation, The deviation(E) changes rapidly. Then manipulation
value(MV) is changed rapidly also. This can cause damage on load or actuator. To prevent this situation, SV can
be changed step by step by parameter setting.
Setting range is 1~4000(Default value is 1). Setting value represents the number of time which taken from
starting set value to last set value.
For example, if SV-ramp is set to 1000 and SV changed from 1000 to 3000 during operation, it changes 2 every
scan and reach 3000 after 1000 scan time.
⑪
Delta MV
This is useful when wants to limit maximum change of manipulation value.
Setting range is 0 ~ 4000 and default value is 4000.
⑫
Bias
The Bias data is used for the compensation of offset in the proportional control. The range of input is 0 ~ 4000.
Be cautious that The actual range of Bias is –2000 ~ 2000. namely, 0~2000 represents 0 ~ +2000 and 2001 ~
4000 represents -1 ~ -2000.
Example> If offset(SV-PV) is 100
→
Bias should be 100.
If offset(SV-PV) is -100
→
Bias should be 2100.
⑬
SV(Target) and PV(Current)
SV (setting value : the designated value) and PV (process value : present value) of MK120S PID operation have
the range 0 ~ 4000. The range is set with the consideration of the resolution of A/D and D/A module of MK120S
series (12bits) and offset value.
⑭
PID Algorithm
In MASTER-K120S, two type of PID algorithm is available, The velocity form(Speed) and positioning form.
Velocity form(Speed) operates incremental manners. Namely, It calculates the change(
∆
n) required from
previous manipulate value(MVn-1), But positioning form calculates an absolute manipulate value(MVn) every
sampling steps. Generally, The velocity form is suit for the system which’s load change is slow like temperature
control system, and positioning form is useful for system which’s load change is fast.
Time
Current SV
Changed SV
SV Ramp = 1
SV Ramp is designates
SV Ramp * Scan time