18
•
TOTAL A B INHIBIT (A
_
bInH)
(Extended counter) displays Total A as Item #1, where
counting may be inhibited by a control input on Channel B. If the menu item
SLOPE
is set
to 0 for Channel B (digit 6), a low input level on B allows counting, and a high input level
inhibits counting. If the
SLOPE
for Channel B is set to 1, the opposite occurs. The
maximum frequency on A that can be counted is 1 MHz. Overflows are displayed as #2.
(See Total A only)
BATCH CONTROL MODE (
_
bAtCH)
BATCH CONTROL WITH A 36.67 PULSE/GALLON TURBINE FLOW METER
Application:
Fill 55 gallon tanks, measur-
ing flow with a 36.67 pulses/gallon flow
meter. Slow down filling at 54 gallons.
Cycle batches automatically with 20 sec
between cycles. Display batch total & fill
rate to 2 places. Track number of batches.
Solution:
Use an Extended counter with a
dual relay output board. Apply the flow
meter signal to Channels A & B. Set Input
to “Rate Batch.” Set Batch to count up to
Setpoint1. Use Gate Time as delay be-
tween batches. Make Item #2 the number
of batches. Set Gate Time to 20 sec. Set
an adaptive moving average filter, which
will apply to rate only, not totals. Set
DecPt1 and DecPt2 to two decimal places
for Items #1 and #3 (Batch Total and Rate).
Scale Item #1 (Batch Total) by entering a
Scale1 of 2.72702 (counts per pulse) and a
Setpoint1 of 55.00, which will serve as the
batch setpoint in gallons. Scale Item #3
(Rate) using the coordinates of 2 points
method so that 36.67 pulses/sec will be
displayed as 60.00 GPM. Set Setpoint2 to
54.00 to activate Relay 2 to slow the fill
rate at 54.00 gallons.
Batch control
(Extended counter) uses the meter with a dual relay controller board to
control repetitive fill operations. Relay #1 is used as the batch relay. Relay #2 (or Setpoint
#2) can be assigned to another limit, such as pre-warn to slow filling near the setpoint, end-
of-process, or rate alarm. The same signal is applied to Channels A and B. When digit 6 of
bAtCH
(Action after Meter Reset) is set to zero, the following applies:
•
In batch control mode without external resets,
the meter waits until the
RESET
key is
pushed. It then energizes Relay #1 and displays the changing Batch Total. When the
preset value is reached, Relay #1 de-energizes for the duration of the gate time setting.
Relay #1 then re-energizes, the Batch Total resets, and the fill cycle repeats.
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