5 Function blocks
5.13 DC, PID controller
Control Relay easy800
11/11 MN04902001Z-EN
www.eaton.com
189
Operating mode
The operating mode defines the value range of the manipulated variable.
Inputs
I1 and I2: The PID controller setpoint and actual values are set at function
block inputs I1 and I2.
KP: Input KP is used to adjust the control difference to the required
proportional gain.
TN: The value for the reset time T
n
at input TN is used for forming the
integral component.
TV: The value for the rate time T
v
at input TV is used for forming the
differential component.
TC: The value for the scan time T
c
at input TC determines the time intervals
in which the operating system calls the function block for processing. If the
value 0 is set, the cycle time of the device is the pause time between the
function block calls.
MV: The set value of the manual manipulated variable M
v
is output on the
output DC..QV as a manipulated variable during activation of coil DC..SE.
You can assign the following operands to function block inputs I1, I2, KP, TN,
TV, TC and MV:
•
Constant.
•
Markers MD, MW, MB.
•
Analog inputs IA01 to IA04:
•
IA01: Terminal I7.
•
IA02: Terminal I8.
•
IA03: Terminal I11.
•
IA04: Terminal I12.
•
Analog output QA01.
•
Output
…
QV of a different function block.
Parameters
Function
UNP
Unipolar 12-bit value: 0 to +4095
BIP
Bipolar 13-bit value: (signed 12-bit value) -4096 - +4095
￫
The device cycle time varies according to the length of the
program. With a scan time of 0 s, this may cause an irregular
control response.
￫
Use the Set cycle time function block
(
section 5.31, “ST, Set cycle time”, page 253) in order to
keep the cycle time of the device constant.
