Rockwell Automation 1771-PD PID MODULE (+DU) - Manual (Page 95)

Programming
Chapter 3
3Ć52
Figure 3.15
Algorithm Flow Chart (3 sheets)
WORD / BIT CALLOUTS
SMIN ABBREVIATION FOR MINIMUM SCALING VALUE
RANGE OF VALUES
PID MODULE WORD NUMBER. LOOP 1 (LOOP 2)
BIT NUMBER. (LOOP 2 NUMBERS ARE IN PARENTHESIS.)
PREFIX M MEANS MULTIPLER BIT(S).
PREFIX S MEANS SIGN BIT.
PREFIX B/B REFERS TO BCD/BINARY FORMAT BIT.
LOGIC STATE 0
LOGIC STATE 1
9999
W31 (W51)
W19 B06
M
S
B/B
NO
YES +
-
SYMBOLS
FUNCTION
DECISION
WRITE BLOCK TRANSFER
READ BLOCK TRANSFER
DOUBLE LINE SYMBOLS MEAN
GO-TO AND RECEIVE-FROM
HARDWARE OUTPUTS
FROM PC PROCESSOR
TO PC PROCESSOR
EXPANDED FEATURES
(SINGLE LINE MEANS
LABELS WITHIN AND BETWEEN
AND INPUTS
STANDARD FEATURES)
PAGES
A A
LEGEND SHEET
THE ALGORITHM FLOW CHART CONSISTS OF TWO PAGES WHICH FOLLOW ON SHEETS 2 AND 3.
THEY ARE SHOWN BELOW IN ABBREVIATED FORM TO PRESENT THE GENERAL SIGNAL FLOW AND TO DEFINE THE SYMBOLS
AND CALLOUTS USED THROUGHOUT. THE BOX AT THE UPPER LEFT DESCRIBES THE WORD/BIT CALLOUTS. THE BOX JUST
BELOW DEFINES THE SYMBOLS.
THERE ARE FIVE FEATURES NOT SHOWN ON THE CHART THAT SHOULD BE SELECTED BEFOREHAND:
1. ONE OR TWO LOOP OPERATION W01 B15
2. STANDARD OR EXPANDED FEATURES W01 B14
3. FOURĆDIGIT BCD OR 12ĆBIT BINARY FORMAT FOR SETPOINT, W01 B11
4. FOURĆDIGIT BCD OR 12ĆBIT BINARY FORMAT FOR ANALOG VALUES, W01 B12
5. SOFT FAULT RESPONSE FOR EACH LOOP, W39 (W59) B15, B14, B13
THE ALGORITHM FLOW CHART CAN BE USED AS A ROAD MAP WHEN PROGRAMMING. BEGIN AT THE ANALOG INPUT
AND FOLLOW THE CHART TO DETERMINE WHICH FEATURES SHOULD BE IMPLEMENTED.
SMIN
ENTER
YES
SCALE
YES
EXPAND
A
START
READ
S
PV
A
ERROR
K D
D
SP
P
I
V
NO
ANALOG
SHEET 2
9999
W31 (W51)
MW19 B06
(MW39 B06)
SW30 B04
(SW50 B04)
MAX/MIN VALUES
LOOP
INPUT
PV
PID
+
-
S
START
FEEDFORWARD
FFI
ENTER TIEBACK
STANDARD
ANALOG
STANDARD
ENTER BIAS
V
S
C
V
BIAS
C
EXPAND
A/D
TIEBACK
11118 SHEET 3
EXPANDED
FEATURES
INPUT W10 (W17)
OR
TIEBACK
B/B W01 B12
LOOP
W08 (W15)
FEATURES
FEATURES
OUTPUT
INPUT
PID