Liquid Controls AN25 - Manual (Page 3)

Sponsler Co., Inc. AN25 Totalizer/Rate Indicator pg. 3 DOC#: MN-AN25
INTRODUCTION
General
The Model AN25 Totalizer and Rate Indicator is comprised of compact, convenient and precision electronics
designed to interface with any frequency generating device such as a turbine flowmeter. The Model AN25 provides
flow totalization and rate in any engineering unit. Total and rate are displayed simultaneously via two 8 digit liquid
crystal displays. A backup battery is incorporated in the Totalizer display circuitry to retain the total until Reset.
Reset is accomplished externally by a magnetic field.
Negatives previously associated with LCD’s – poor cold temperature performances, condensation which is a by
product of heaters and display ghosting – have all been eradicated by incorporating a low temperature coefficient
LCD (-35
o C).
In addition to totalization and rate indication, the Model AN25 (Analog) provides an interface 4-20mA output and an
interface voltage output of 0-5V or 0-10V, selectable. The AN25 (Analog) linearly converts a frequency to
equivalent analog outputs of 4-20mA and 0-5V or 0-10V. When incorporated with a turbine flowmeter, interface
outputs of 4-20mA and 0-5V or 0-10V proportional to flow are obtainable.
An input supply voltage of 110VAC or 12VDC is standard.
The Model AN25-L is a Loop Powered Totalizer & Rate Indicator which accepts a 4-20mA Loop Powered Input.
Model AN25-L provides the same totalization and rate indication as the Model AN25.
Theory of Operation
Model AN25 amplifies and shapes the incoming pulses generated by the turbine's response to flow. The amplified
pulse train is factored by a phase locked loop (PLL). The factored pulse train is then scaled & divided to produce a
totalized display in the desired engineering unit. For rate, the divided pulse train is combined with a crystal
timebase for absolute accuracy. This configuration permits the calibration factor to be universal for both total and
rate indication.
Model AN25-L Loop Powered Totalizer & Rate Indicator accepts a 4-20mA loop input. An analog to frequency
converter is incorporated in the circuitry to establish a calibrated 10KHz full scale frequency pulse. This pulse is
then scaled and divided by the same circuitry as the standard AN25 to provide totalization and rate indication in
engineering units.
Calibration
Field calibration for Totalization and Rate is accomplished by incorporating a calibration factor based on the turbine
K-Factor. Divider switches provide divisional increments of .00000001 – 1.9999. The calibration factor is entered
via 4 BCD switches, a divider switch, and a ‘0-1’ switch.
Calibration of the analog control outputs is established by installation of a F/S frequency jumper in conjunction with
the zero and span adjustments. 0-5 or 0-10VDC output is selected by installation of a jumper. 4-20mA and 0-5/
0-10V calibrations are independent of each other and independent of the calibration factor entered for total and rate
indication.