The PFS FML250 Liquid Flow Monitor calculates and displays real-time liquid flow rate and total. It pairs with Turbines, Inc. turbine meters and other frequency-generating flow devices. A front keypad simplifies programming, while the two-line LCD provides clear local process information.
The FML250 supports 2–40-point linearization and automatic K-factor correction. These functions help users optimize the monitor for a connected flow meter. The auto-ranging rate display also adjusts the displayed value as operating conditions change.
A scalable pulse output comes standard with the FML250. Users can also select an optional 4–20 mA loop output with programmable low and high values. In addition, the monitor supports battery-powered or externally loop-powered operation.
Optional temperature compensation uses a two-wire PT1000 RTD sensor. However, temperature compensation does not come with the intrinsically safe FML250-IS configuration. The standard FML250 carries CSA/US certification and uses a NEMA 4X polycarbonate enclosure.
Westech Industrial supplies the PFS FML250 across Canada. Our team can assist with application review, configuration selection, service support, and custom fabrication. Therefore, customers can integrate the monitor into a complete flow measurement solution.
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Description
Simultaneous Rate and Total Display
The FML250 Liquid Flow Monitor provides two independent LCD display lines. This layout allows users to view liquid flow rate and accumulated total at the measurement point.
The rate display automatically adjusts its range for easier reading. Its display specification reaches ±0.01% of the reading for rate. The total display specification reaches ±1 count.
Users can configure rate values per second, minute, hour, day, or a custom period. The monitor also supports several engineering units. These include gallons, cubic feet, litres, cubic metres, barrels, pounds, kilograms, and thousand cubic feet. A custom engineering unit provides further flexibility.
Multi-Point Flow Linearization
The FML250 supports between two and 40 linearization points. This capability allows the monitor to account for variations across a connected meter’s operating range.
Automatic K-factor correction further simplifies configuration. Consequently, users can match the monitor more closely to the flow meter’s calibration information.
EEPROM retains the configured parameters without relying on continuous power. A secondary storage location also protects the parameters and linearization table. This design helps preserve important settings during maintenance or battery replacement.
Configurable Pulse Output
The standard FML250 includes a factored pulse output. It uses an opto-isolated open-collector output rated for 150 mA and 30 VDC maximum.
Users can configure frequency output or select a fixed pulse width. Available pulse widths include 2, 5, 10, 50, 100, 250, and 500 milliseconds. The monitor also supports a custom pulse-width setting.
Pulse output dividers include 1, 10, 100, 1,000, and custom values. In addition, pulse multipliers provide 0.01 and 0.1 scaling options. These settings help match the output to downstream monitoring or control equipment.
Optional Scalable 4–20 mA Output
An optional factored 4–20 mA rate output supports connection to compatible control and monitoring systems. Users can program the low and high scaling values to match the required flow range.
The factored rate output carries a specification of ±0.3% of reading. It also supports loop-powered operation from 7.5 to 36 VDC.
This output option provides a continuous analog representation of the measured flow rate. Therefore, it can support remote indication, recording, or integration with compatible automation equipment.
Flexible Input and Power Options
The FML250 accepts sine-wave and square-wave pulse inputs. Its field-adjustable signal input covers frequencies from 0 to 6,000 Hz. It also supports signal levels from 50 mV to 36 V with 10 kΩ input impedance.
A lithium primary D-cell battery comes standard. An alkaline 1.5 V D-cell clip remains available as another option. Selectable power modes allow users to balance display performance and battery life.
Alternatively, the monitor supports external loop power. Reverse-polarity protection helps protect the electronics during wiring and commissioning.
Built-In Testing and Diagnostics
The FML250 includes a built-in test system for troubleshooting and commissioning. Users can simulate pulse and 4–20 mA outputs without separate signal-generation equipment.
The test suite also displays battery voltage and raw flow meter input frequency. These diagnostic values help technicians verify the incoming signal and monitor condition.
Automatic maintenance reminders support planned service activities. Flow-rate warnings can also alert users when operating conditions reach configured thresholds.
Rugged Enclosure and Mounting Choices
The standard FML250 uses a polycarbonate enclosure with a NEMA 4X rating. It operates from -22°F to +150°F.
Available mounting arrangements include direct meter mounting, swivel or pedestal mounting, and wall mounting. The wall-mount configuration includes a 30-foot signal cable.
These choices allow users to place the display near the meter or at a more accessible viewing location. The complete monitor weighs approximately two pounds.
Optional Temperature Compensation
The standard FML250 can include temperature compensation with a two-wire PT1000 RTD sensor. The option includes a 1,000-ohm RTD and a 36-inch temperature cable.
The temperature-compensation range extends from -328°F to +1,000°F. Its accuracy reaches ±0.03% of full scale at 75°F.
However, the intrinsically safe FML250-IS does not offer temperature compensation. Westech can help confirm the correct configuration for each installation.
Intrinsically Safe Configuration
The FML250-IS provides an intrinsically safe option for applications that require approved equipment. This model carries CSA/US and IECEx approvals and an IP66 enclosure rating.
The FML250-IS supports wall or swivel mounting. However, it does not support direct meter mounting or temperature compensation.
Because hazardous-location requirements vary, users should confirm the complete approval and installation requirements before ordering.
Applications
The PFS FML250 Liquid Flow Monitor supports applications that require local rate indication, totalization, or retransmission. Its configurable input, output, power, and mounting options suit many liquid flow monitoring systems.
- Local flow rate and accumulated total indication
- Turbine flow meter monitoring
- Other frequency-generating flow devices
- Battery-powered flow monitoring locations
- Systems requiring scalable pulse retransmission
- Systems requiring a 4–20 mA flow signal
- Applications requiring multi-point flow linearization
- Temperature-compensated liquid measurement with the standard FML250
- Hazardous-location installations using the FML250-IS
- Custom-fabricated flow monitoring panels and packaged systems
Manufacturer info
Primary Flow Signal designs and manufactures flow measurement solutions for liquid, gas, and steam applications. Its product offering includes Venturi flow meters, wedge-type meters, orifice flow elements, flow nozzles, and custom-engineered differential pressure measurement products for industries such as water and wastewater, oil and gas, power generation, industrial processing, automotive, and cryogenic service.
