Product Overview
The PFT-420 family are RecordALL’s analog flow transmitters — they take the pulses from a meter’s register drive, sensed by a reed switch inside the transmitter, and put out a two-wire 4–20 mA DC signal directly proportional to flow rate, plus an open-collector digital pulse for a totalizer or batch controller. The loop is powered on the same two wires (10–36V DC), the outputs are isolated from supply negative, and the signal holds ±0.5% of point over a 10:1 range. The factory calibrates the span to your meter and full-scale flow; if that changes, the span and zero adjust on screws in the field. Three current nameplates cover the line: PFT-420 for RCDL 25–70 disc meters, PFT-420/2 for industrial turbo, and RST-420 for the larger RCDL 120/170 — the cast-bronze FT-420B was discontinued by Badger Meter in 2021 (service parts only) and is replaced by the plastic PFT-420. Each mounts on the meter register in a NEMA 4X plastic housing.
One platform, four nameplates
All four are the same reed-switch analog flow transmitter — an isolated two-wire 4–20 mA DC output proportional to flow, plus an open-collector digital pulse, 10–36V DC loop-powered, ±0.5% of point. They differ only by the meter they mount on and the housing.
- RCDL Models 25, 35, 40 and 70 (5/8–1 in) disc meters
- NEMA 4X plastic housing
- RCDL Models 25, 35, 40 and 70 disc meters
- NEMA 4X cast-bronze housing — where a metal enclosure is preferred
- Discontinued by Badger Meter in 2021 — service parts only until stock is depleted; the plastic PFT-420 is the current equivalent
- Industrial Turbo meters (2, 3, 4 and 6 in)
- NEMA 4X plastic housing
- RCDL Models 120 and 170 (1-1/2 and 2 in) disc meters
- remote-style housing
Key Features & Benefits
- Isolated two-wire 4–20 mA — an analog output that tracks flow rate over a 10:1 range, loop-powered on two wires and isolated from supply negative
- Analog plus a digital pulse — one transmitter feeds both an analog input and a digital totalizer or batch controller — the open-collector pulse tracks the meter pulses
- Reed-switch simple, solid-state reliable — a reed-switch sensor and solid-state circuitry; reversed-polarity protection and a resettable over-voltage fuse
- Factory-calibrated, field-adjustable — calibrated to your meter and full-scale flow at the factory; the span and zero adjust on screws if the full-scale flow changes
- Matched to the meter and the duty — PFT-420 for RCDL 25–70 disc meters (the cast-bronze FT-420B was discontinued in 2021), PFT-420/2 for industrial turbo, RST-420 for the larger RCDL 120/170 — we match the nameplate to your meter
Specifications
- Function
- A flow transmitter that converts a meter’s register-drive pulses into a two-wire 4–20 mA DC signal proportional to flow rate, plus a digital pulse output — for a PLC, DCS, totalizer, batch controller or chart recorder
- Models
- PFT-420 (plastic, RCDL 25/35/40/70 disc meters); PFT-420/2 (plastic, industrial turbo); RST-420 (RCDL 120/170); FT-420B (cast-bronze, RCDL 25/35/40/70) — discontinued by Badger Meter in 2021 (service parts only), replaced by the plastic PFT-420
- Sensing
- A reed-switch sensor inside the transmitter assembly, driven by the meter register; input pulses are converted to the analog and digital outputs
- Output
- A 4–20 mA DC two-wire signal directly proportional to flow rate, plus an open-collector transistor digital pulse (80V DC max, 200 mW, 1 ms ± 0.1 ms pulse width) compatible with most totalizers and batch controllers
- Pulse resolution
- Set by the meter K-factor (pulses per US gallon); the factory calibrates the span to the meter and full-scale flow on the order, and the span is field-adjustable on a screw (7–24 mA span, 3–9 mA zero)
- Meter compatibility
- Badger Meter RCDL disc, oscillating-piston and industrial turbo meters — the four nameplates cover the line by meter type and housing (see Variants)
- Power
- 10–36V DC, drawn from the two-wire control loop; reversed-polarity protected, with a resettable 100 mA over-voltage fuse
- Isolation
- The 4–20 mA and pulse outputs are isolated from power-supply negative
- Enclosure
- NEMA 4X — plastic on the PFT housings, cast bronze on the FT housing
- Mounting
- Meter-register-mounted on the PFT/FT housings; the RST-420 is a remote-style housing
Common Applications
- 4–20 mA flow into a PLC, DCS, recorder or data logger
- Pulse totalizing or batch control off the open-collector digital output
- Process-control flow measurement — chemical, food & beverage, water conditioning, pharmaceutical
- Remote analog signal off a disc, OP or industrial-turbo meter
Design & Selection Considerations
- Two-wire 4–20 mA budget — check the loop resistance — the PFT-420 is a two-wire loop-powered transmitter: the same pair carries the 4–20 mA signal and the 10–36V DC supply, and the maximum load the loop can drive is 50 + 50 × (VDC − 10) ohms. Size the supply voltage to the loop’s total resistance (sense resistor plus wire) before you wire it. Use the input form to send your supply voltage and run length and we’ll confirm the loop budget.
- The span is calibrated to the meter — tell us the full-scale flow — the 4–20 mA span is set to a specific full-scale flow using the meter’s K-factor (pulses per US gallon), so the transmitter is meter- and range-specific. The factory calibrates it on the order; if the full-scale flow later changes, the span adjusts on a screw against a milliammeter rather than needing a new unit. Use the input form to send your meter model and the full-scale flow the 20 mA point should represent.
- Not for hazardous locations — the PFT-420 family is not intended for use in hazardous (classified) locations and carries no Ex rating. For a Division/Zone area, the transmitter must sit in a safe location or the signal taken off the meter another way — tell us the area classification up front so we route the signal correctly.
- Pick the analog transmitter only when you need a 4–20 mA loop — if the receiving device takes a pulse rather than an analog input, a register-driven pulse (the HR-E LCD encoder scaled pulse) or the high-resolution PEPT-1 / EPT-1XP is the simpler, lower-cost path; the PFT-420 earns its place where the PLC, DCS or recorder input is 4–20 mA. Use the input form to tell us what the receiving input is and we’ll match the output.
To size & select the right 4-20 mA flow transmitter:
Use the input form to tell us the meter and what the read-out has to do — a local total, a resettable rate / total counter, a scaled pulse or 4–20 mA into a PLC or SCADA, batch control, or a cellular cloud read — and we’ll match the register, transmitter or controller to it.
Flow Meter Application Sheet ›Talk to an engineer directly — Scott Prater, Principal · 917-580-0878 · scott@pratertechnical.com
Specifications compiled by Prater Technical Partners from Badger Meter RecordALL commercial & industrial water-meter product literature.