Allen-Bradley SLC 500 Series

Publication 1747-RM001G-EN-P - November 2008
Proportional Integral Derivative Instruction 9-31
In this program, cycle time is the preset of timer T4:0. Cycle time relates to
% on-time as follows:
Example - Time proportioning outputs
T4:0.PRE is the cycle time
% on-time
100% output on-time
(L)
O:1.0
0
(U)
O:1.0
0
(RES)
T4:0
(EN)
(DN)
TIMER ON DELAY
Timer T4:0
Time Base 0.01
Preset 1000
Accum 0
NOT EQUAL
Source A N7:25
0
Source B 0
GREATER THAN
Source A T4:0.ACC
0
Source B N7:25
0
MULTIPLY
Source A N7:1
0
Source B T4:0.PRE
1000
Dest N7:25
0
DOUBLE DIVIDE
Source 16383
Dest N7:25
0
CLEAR
Dest S:5
0
PID
Control Block N7:2
Process Variable N7:0
Control Variable N7:1
Control Block Length 23
END
] [
T4:0
DN
] [
N7:2
13
PID
TON
GRT
NEQ
MUL
DDV
CLR
Cycle Time of Output
Time Proportioning
Output Contacts
Control Variable
Output as a Fraction of
Cycle Time
Clears Minor Error Flag
PID Instruction
Done Bit