Model M1715A Maxiflex 2PFC Module0 pages

Maxiflex 2PFC Precision Frequency Counter Module
Model M1715A 2 Channel High Precision Frequency Counter Module.

DATASHEET
FEATURES
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2 individually Isolated Frequency Counter Channels

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Interfaces to two Vibrating Tube Densitometers

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Measures 1Hz to 5kHz at 15ppm accuracy

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Outputs period of incoming frequency in nanoseconds

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Accepts 9-30Vdc or 3 to5Vdc Pulse Input

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Fits in any MAXIFLEX base I/O slot

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1500V rms Isolation

The M1715A high precision frequency counter
module provides individually isolated field inputs to
two 32-bit frequency counters. The counters are
designed to operate in the range 1Hz to 5Khz and
return the period in nanoseconds of each input to
an accuracy of better then 15ppm.
A target application for this module is as interface
to vibrating tube densitometers to allow the highest
accuracy of frequency to be measured in oil and
gas custody transfer applications.
Liquid density is one of the many parameters to be
accurately measured for product quality control,
custody transfer, process control, or liquid interface
detection purposes. In the hydrocarbon industry,
the vibrating tube densitometer is most common. In
this type of densitometer, a tube of known mass is
vibrated at its natural frequency. As the tube is
filled with the process fluid, the frequency will be
damped proportionate to the density of the
material. Other variables, such as specific gravity,

molecular weight, Brix and concentration can be
derived from this measurement if required. The
mass is related to the mass of the tubing plus the
mass of the fluid inside the tubing. As the mass (or
density) of the fluid in the tubing varies, the natural
frequency varies. Because of the relative mass of
the tube to the process fluid in the tube, the
measurement of frequency must be highly accurate
to achieve satisfactory results. The high accuracy
of the Maxiflex 2PFC module makes it ideal for this
measurement application.
The 2PFC module should be used in conjunction
with dedicated software to be used as part of the
user application. For use with Isagraf compatible
CPUs use the Omniflex supplied function block
“cn74_t”. For use with Forth compatible CPUs, ask
Omniflex for the necessary eziForth words.
Each input may be configured by links inside the
module to either be a 3-5V dc, or a 9-30V dc input
to support the widest range of densitometers.

SPECIFICATIONS
Input

Environmental

Number

2 Frequency Inputs (Inputs 1 and 2)

Operating Temperature

Type (Two Ranges)

9-30Vdc (default) or 3-5Vdc Pulses

Storage Temperature

Input Current

Standard: 2.6mA at 9V; 10mA at 30V
Low: 2.6mA at 3V; 8mA at 5V

Humidity

95% max. at 40°C (104°F) non-condensing.

Input Isolation

100% tested to 1500Vac for 1 minute

Protection

Electronics conformally coated

Insulation Resistance

1000MΩ min. at 500Vdc

Input Indication
(Green LED per channel)

LED on channel Active
LED off channel Inactive

Input Range

1Hz to 5kHz

Module ID

126

Period Measurement Range

200,000 to 1,000,000,000 nanosec.

Scan Code

127

Screw Terminal Wire Size

-40°C to +70°C (-40°F to +158°F)

Logic Power Consumption
From Logic Power Supply

60mA from 5Vdc max.

Auto Identification Codes

Mass

InputTermination
Types

-25°C to +60°C (-13°F to +140°F)

Screw clamp Plug-in Terminal Blocks
and 20 way ribbon header

Excluding Packaging

320g (11.3oz)

Including Packaging

410g (14.5oz)

2

2.0mm maximum
For manageable wiring to the module, 0.5
mm2 is recommended with 2mm overall
outside diameter

Ordering Information
Model

Order Code

Maxiflex 2PFC

M1715A

Copyright Omniflex ♦ Subject to change without notice

Datasheet DSM1715AR02 sheet 1 of 2

http://www.omniflex.com

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