Applications 5-5
Series
505 High Speed Counter
and Encoder Module User
’
s Manual
5.2 Flow Rate Example
5.2.1
Description A
flow meter outputs 200 pulses per gallon. The program requires
calculation of flow rate in gallons per minute (GPM).
5.2.2
Solution
Configure the HSC as WX9–WX1
1, WY12–WY16. Attach channel 1 to the
flow meter
. The HSC accumulates flow meter pulses for the duration of a
1-second fast timer
. In the controller
, accumulated pulses are scaled to
GPM by the following calculation (using the controller memory locations).
Equation: GPM = Pulses per Sec 60 ?200
Program Locations: (V23,V24) = (WX10) (V20) ?(V19)
Following each calculation, reset the HSC, restart the T
imer
, and perform
a new calculation 1 second later
.
TMRF2
P= 01.000
C23C20
BITC1
A:
N=
WY12
1
C25C23
MULT1
A: WX10
DIV1
A: V21
BITS1
A:
N=
WY12
1
C24C23
C23
C23
C25
C24
: ONE
SECOND TIMER HAS EXPIRED, COMPUTE FLOW
RESTAR
T TIMER ON NEXT SCAN
:
SCALE COUNTER V
ALUE IN GALS/MINUTE PUT RESUL
TS
IN LOCA
TIONS V23–V24, RESET HSC CHANNEL 1
:
TURN OFF CHANNEL 1 RESET T
O HSC
B:
C: V20
V21 B:
C: V19
V23
Figure 5-5 Ladder
Logic for Flow Rate Example