-25-
EXCITATION (Optional)
The optional regulated excitation voltage (18 VDC, 60 mA max.) can be
used to power the transducer. The common of the excitation voltage is
internally connected to “COMM” (TBA #5). The excitation voltage is NOT
to
be used for powering relay coils, serial communication loops, etc., due to the
sensitive nature of signal common.
TOTALIZER/LINEARIZER/PEAK/VALLEY/TARE
(Optional)
TOTALIZER
The totalizer option simply totals (adds) input readings together using a
programmable time base and scaling coefficient. The decimal point position of
the totalizer can be programmed independent of the input signal. The totalizer
may be reset through a remote input, by the front panel or through the serial
communications option. Alarms may be programmed to trigger from totalizer
values; for example to total flow for batching operations. The programmable time
bases are “per second”, “per minute” and “per hour”, meaning the totalizer will
accumulate at a fixed rate of 2
1
2
times per second and be equal to a fixed input
signal level over the selected time period. For example, if the input signal is a
constant 1000 units and the “per minute” time base is selected, the totalizer will
accumulate at the rate of 1000 units per minute. The totalizer is updated at this rate
every 400 msec. As a result, the input signal is accumulated in “batches” of 6.6
counts every 400 msec. Therefore, the totalizer start and stop sequencing, as well
as the alarm values set to trigger at specific totalizer values, are accurate only to
the 400 msec totalizer update rate. The preceding example requires a scale factor
of 1.000 to yield exact time bases, but any scale factor can be used to span between
the ranges. (See section on totalizer programming for detailed information.) A
programmable low signal level disable feature completes the totalizer features
(this will stop totalization when the signal level drops below this programmed
value, “low cut”). At loss of power to the indicator, the contents of the totalizer are
saved. This will allow totalizing over consecutive shifts, days, etc. The total can
accumulate to 999,999. If the low-end cutout value is programmed negative (ex.
-100, reference Program Module #5), and the input signal is between zero and the
low-end cutout value, the totalizer value will decrement. If the input signal goes
above zero the total will increment. If the signal goes below (more negative than),
the low-end cutout value, totalization will stop.
Note: The totalizer value will roll over and flash when the total exceeds,
999999 or -99999, indicating an overflow condition. Reverse signal input
will cause the totalizer value to count in the opposite direction and
eventually no longer be in an overflow condition.
TOTALIZER EXAMPLE
The indicator is employed to indicate and totalize the natural gas consumption
of a factory. A gas flow meter with a linearized 0-5 VDC output that corresponds to
0 to 250 CFM is selected. The input is scaled to read the actual gas flow in cubic
feet per minute (CFM) with 0.01 CFM resolution and the totalizer is scaled to
indicate total cubic feet used. The ±20 VDC range is selected. In order to hold and
display larger values, the totalizer is scaled to display the total gas usage (cu. ft.) in
hundredths. The following programming steps are followed:
BASIC SET-UP
“Pro 1 or 2”.....“dECPNt” - 0.00
“round” - 0.01
“dSP 1” - 0.00
“INP 1” - 0.000
“dSP 2” - 250.00
“INP 2” - 5.000
TOTALIZER SET-UP
With an average signal input which gives a Process Display of 250.00 CFM
for a one-minute time period, the following formula applies:
S.F. =
D.T.
x (
T.B.
)
*
x
D.T.D.P.
I.D. TIME I.D.D.P.
S.F. = Programmable Scale Factor
D.T. = Desired Totalizer value for a
fixed time duration
T.B. = Programmable Time Base
T.B. = If Program Select Number Chosen Is:
Enter in Formula
“0” for sec. 1
“1” for min. 60
“2” for hr. 3600
I.D. = Input Display Value
TIME = Actual Time period in seconds
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