Flwa (Analog Flow Totalizer) - IDEC MICROSmart FC6A Series Ladder Programming Manual

FLWA (Analog Flow Totalizer)

This instruction samples the instantaneous flow (volume per unit of time) and stores the accumulated flow volume (the volume of
a material that has passed through for an arbitrary period) to a log.
Symbol
FLWA S1
*****
Operation
The flow rate is sampled at a fixed cycle and the accumulated flow volume is calculated. That result is stored in the device
specified by D2 (logged data).
The FLWA instruction has a totalizer function that samples and accumulates the flow rate and a log output function that
temporarily saves the accumulated volume at the desired time.
Note: When using an analog output type flow meter, the FLWA instruction can be used to monitor the flow volume by converting the analog value
output from the flow meter to the flow rate with the SCALE instruction.
For details on the SCALE instruction, see "SCALE (Convert Analog Input)" on page 27-1.
When using a pulse output type flow meter, the FLWP instruction can be used to monitor the flow volume. For details on the FLWP instruction, see
"FLWP (Pulse Flow Totalizer)" on page 27-18.
Notes:
• The FLWA instruction cannot be used in an interrupt program. If used in an interrupt program, a user program execution error occurs, the
execution of the instruction is canceled, and the next instruction is executed.
For user program execution errors, see "User Program Execution Errors" on page 3-10.
• The FLWA instruction cannot be simultaneously used with the LABEL, LJMP, LCAL, LRET, JMP, JEND, MCS, and MCR instructions.
Totalizer Function Overview
When the input is on, if the enable totalizer input (S2) is turned on, the flow rate (S1+0, S1+1) starts being sampled.
When the enable totalizer input is on, totalization is performed (updating the accumulated flow volume work area and
accumulated time work area).
When the enable totalizer input is off, totalization is paused. (The accumulated flow volume work area and the accumulated time
work area values are retained.)
Enable totalizer input (S2)
Flow rate
(S1+0, S1+1)
Accumulated flow volume work area
(D1+4, D1+5)
Accumulated time work area
(D1+6, D1+7)
Note: For details on the totalizer function such as the operation immediately after the input is turned on and the operation when the enable totalizer
input (S2) is once again turned on, see "Totalizer Function" on page 27-11.
S2 S3 D1 D2
***** ***** ***** *****
ON
Input
OFF
ON
OFF
Sampling
period
FC6A S MICROS
ERIES MART
27: F
L P M
ADDER ROGRAMMING ANUAL
C
LOW ALCULATION
FC9Y-B1726
I
NSTRUCTIONS
27-9