Scl & pulser assembly – Fill-Rite TS06 LPG Precision Meter User Manual
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SCL & Pulser Assembly
SCL
(Scaler/Calibrator/Linearizer)
Description:
Tuthill SCL is a small electronic device de-
signed to provide the function of a pulse Scaler, an electron-
ic Calibrator and Linearizer. This electronics package
replaces a mechanical gear plate and mechanical calibrator
while at the same time providing the ability to improve the
accuracy of a metering device during low flow operation,
thus improving the overall meter accuracy, and extending
the flow range of the metering device. The SCL may be
used in conjunction with other Tuthill electronics to solve
many of your electronic interface requirements.
Specifications:
Input Voltage
:
5Vdc and 6 to12 Vdc
Input Current
:
25ma @ 5Vdc
Operating Temperature: -40
o
C to +85°C
(U/L T4 upper limit is +40C)
Input signal
: Hall Effect sensors, single or
dual,
or
single
ended
input
from 5Vdc logic
Input Frequency
:
2000 Hz (max)
Output:
Quadrature Pulse
Output Voltage
:
Proportional to
power supply voltage
Duty
Cycle
: Symmetrical
Quadrature
with 50/50 D.C.
Output Frequency
:
(Input Frequency) X (ECF)
Scaled to application
Linearizer :
32
points
maximum
Calibrator Range
:
+/- 3.0%
Output pulse on-time :
Fixed by firmware
OPERATION:
The SCL may be used to perform a number of functions
depending upon the users application. The following is a
brief description of several of the SCL functions.
SCALER MODE:
When operating in the Scaler mode only, the SCL applies a
single error correction factor (ECF) to the incoming pulse
signal. If a single correction factor is applied to the entire
range of meter frequency inputs then the output frequency is
proportional to the input frequency times the ECF (SCL
Pulses out = SCL Pulses in times ECF). If the ECF is 1.0
(no scaling factor) the output frequency is equal to the input
frequency.
As an example, use this feature when the customer’s elec-
tronics requires a precise frequency or pulse resolution in-
put. If the customer’s electronics required 100 pulses per
liter, then 100 PPL becomes the base pulse resolution
based on which all input pulses are scaled. If, as an exam-
ple, the meter is providing 108 pulses per liter, then an ECF
of 0.925 (100/108) would be programmed into the SCL, and
the output pulse frequency would be equivalent to the se-
lected base resolution of 100 PPL.
LINEARIZER MODE:
If a metering device is not producing an output within the
limits of accuracy required for an application, the SCL may
be used as a linearizer. A linearizer is a device, which rec-
ognizes the output frequency of the metering device, and
applies a correction factor (ECF), chosen for that frequency
to improve the accuracy of the metering device.
The number of ECF points chosen for a specific application
depends upon the accuracy of the metering device. In
weights and measure applications, there is an ECF applied
at each flow rate point where the meter accuracy varies by
0.25% from the previous flow rate point.
The ECF data is stored electronically in the SLC at the facto-
ry . The electronic chip storing this data is permanently at-
tached to the printed circuit board. The ECF chip is marked
with a code, that is used to reference the exact set of ECF
data, that is supplied in your SCL device.
CALIBRATOR MODE
:
The SCL is equipped with two rotary switches
S3 and S4,
and a two position switch
S2. The three switches allow the
SCL to adjust the pulse output up or down by 3%.
This allows the operator, or W&M authorities to calibrate the
meter without having to alter scale factors in customer elec-
tronics. This feature is designed to replace mechanical cali-
brators used in the field for years to adjust the meter output
to accurately match the volume in a proving vessel.
The calibrator feature may be used if the SCL in being used
as a scaler only, or as a scaler/linearizer.
SWITCHES:
S1 :
Allows the choice of either a single channel input,
or a two channel quadrature input.
S2 : Is used in conjunction with S3 and S4.
If in the minus (-) position, an increase in the S3 and
S4 switch settings will decrease the pulse output. A
decrease in pulse output will increase the volume in
a prover vessel. If in the plus (+) position, an in-
crease in the S3 and S4 will increase the pulse out-
put. An increase in pulse output will decrease the
volume in the prover vessel.
S3/S4 Adjust the SCL pulse output up or down +/-3.0%.
S3 and S4 will allow for 00-99 settings. Each incre-
ment changed in this setting, changes the SCL
pulse output by approximately 0.03%