Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual MV = KP * Et + KI * EtS1 + KD * PV t S

PID equation

E(t) = SV – PV

E(t) = PV – SV

DVP-ES2/EX2/SS2/SA2/SX2/SE Operation Manual - Programming

yPID equation for control mode k0~k2:

MV = KP * E(t) + KI * E(t)S1 + KD * PV (t )S

where

MV : Output value

KP : Proprotional gain

E(t): Error value

PV (t): Present measured value

SV (t): Target value

KD : Derivative gain

PV (t)S : Derivative value of PV(t)

K I : Integral gain

E(t) S1 : Integral value of E(t)

yWhen E(t) is smaller than 0 as the control mode is selected as forward or inverse, E(t) will be regarded as “0"

Control mode

Forward, automatic

Inverse

yControl diagram:

In diagram below, S is derivative operation, referring to “(PV﹣previous PV) ÷ sampling time”. 1 / S is integral operation, referring to “previous integral value + (error value × sampling time)”. G(S) refers to the device being controlled.

PID operation is within dotted area

+

1/S	K I
K P	+	+
		G(s)
		+
		K D

S

yThe equation above illustrates that this operation is different from a general PID operation on the application of the derivative value. To avoid the fault that the transient derivative value could be too big when a general PID instruction is first executed, our PID instruction monitors the derivative value of the PV. When the variation of PV is excessive, the instruction will reduce the output of MV/.

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