Key Technical Specifications
| Parameter | Value |
|---|---|
| Input Signal | 4–20 mA DC (170 Ω impedance), direct action |
| Output Signal | 3–15 psi (20–100 kPa) |
| Accuracy | ±1.0% of span |
| Linearity | ±0.5% of span (typical) |
| Repeatability | ±0.25% of span (typical) |
| Hysteresis | ±0.5% of span (typical) |
| Dead Band | 0.1% of span |
| Supply Pressure | 1/4 NPT air supply connection |
| Operating Temperature | 0°C to 60°C (32°F to 140°F) |
| Enclosure Rating | IEC IP65 / NEMA Type 4 |
| Approximate Weight | 2.3 kg (5 lbs) |
| Mounting | Surface, valve yoke, or nominal DN 50 / 2-inch vertical pipe |
Product Introduction
I’ve pulled more E69F converters off pipe racks than I can count. This thing is a workhorse — a simple, no-nonsense I/P transducer that takes your 4–20 mA signal from the DCS or controller and spits out a clean 3–15 psi air signal to position a control valve. No firmware to flash, no configuration software to fight with. You wire it up, set your air supply, adjust the zero and span screws, and it runs.That simplicity is exactly why plants still rely on these decades after they went obsolete. The galvanometer motor design gives decent clearance between the coil and housing, which means dust and moisture don’t kill it the way they do with voice-coil-type instruments. The rigid feedback structure handles vibration well — I’ve seen these survive on compressor skids where other converters rattled themselves to death within a year. Accuracy holds at ±1.0% of span, which is more than adequate for valve positioning.One thing to watch: the E69F is calibrated for vertical mounting by default. If you’re bolting it on a horizontal surface or at an angle, you’ll need to recalibrate at the installed position or accept up to 0.25% zero shift per 5° of tilt.
Quality SOP & Tech Pitfalls
The Lab Report (Pre-Shipment Testing)
- Visual & counterfeit inspection: Check the die-cast aluminum housing for casting marks, verify the data plate is pressure-sensitive adhesive (not engraved into suspect metal), and confirm the 1/4 NPT ports are clean and undamaged.
- Bench test on air supply: Hook it to a regulated 20+ psi air source, inject 4 mA and 20 mA from a loop calibrator (Fluke 789 or equivalent), and verify the output reads 3 psi and 15 psi respectively.
- Mid-span linearity check: Inject 12 mA — output should read 9 psi ±1.0% of span.
- Insulation resistance: Megger the electrical input terminals to the housing ground at 250 VDC to confirm isolation integrity.
- Zero and span adjustment verification: Confirm both adjustment screws turn freely and hold position without drifting.
- Anti-static packaging and sealing before shipment.
The Engineer’s Warning
Here’s where people mess this up:Pitfall #1 — Swapping without noting direct vs. reverse action. The E69F-BI2 is direct-acting (increasing current = increasing pressure). If your old unit was reverse-acting, a direct-acting replacement will drive the valve the wrong direction. Check the model code suffix carefully — the “I” in “BI2” indicates input range and action direction.Pitfall #2 — Ignoring the supply air quality. This converter has a 1/4 NPT air supply port but no integral filter regulator unless you ordered the “-R” suffix. I’ve seen supply air contaminated with compressor oil gum up the nozzle/flapper assembly and cause the output to stick at full pressure. If your air supply isn’t clean and dry, install an external filter-regulator upstream.
Installation & Configuration Guide
- ⚠️ Pre-Installation Safety
- Isolate the control valve from the process if possible.
- Block and bleed the air supply line.
- Disconnect the 4–20 mA loop and verify zero current with a multimeter.
- Take a photo of the old unit’s mounting orientation, tubing connections, and wiring before removing anything.
- Removal
- Label the air supply tube, output tube, and electrical leads.
- Disconnect the 1/4 NPT air fittings using two wrenches (one to hold the converter body, one to turn the fitting).
- Remove the mounting hardware (surface bolts, yoke clamp, or pipe strap).
- Installation
- Mount the replacement E69F in the same orientation as the original — vertical is preferred.
- Reconnect the 1/4 NPT air supply and output tubing. Use Teflon tape or pipe dope on the threads.
- Wire the 4–20 mA input to the 1/2-inch conduit connection using 18 AWG twisted pair leads.
- Calibration & Commissioning
- Apply air supply (minimum 20 psi for a 3–15 psi output range).
- Inject 4 mA — adjust the zero screw until output reads exactly 3 psi.
- Inject 20 mA — adjust the span screw until output reads exactly 15 psi.
- Repeat zero/span adjustment 2–3 times until both points are stable.
- Verify mid-span at 12 mA (should read 9 psi).
- Return the loop to automatic control and monitor valve response.
Compatible Replacement Models
| Model | Compatibility | Notes |
|---|---|---|
| FOXBORO E69F-BI2 | ✅ Drop-in Replacement | Exact same unit — verify your nameplate reads “BI2” not “B12” |
| FOXBORO E69F-BI3 | ⚠️ Mechanical Fit, Different Output | Same enclosure and input, but output is 1–18 psi instead of 3–15 psi. Do NOT substitute unless your valve actuator accepts that range. |
| Fischer & Porter / ABB I/P converters | ❌ Hardware Mod Required | Different mounting, tubing connections, and calibration procedures. Only consider if doing a full instrument upgrade. |
Frequently Asked Questions
Can I use the E69F-BI2 with a 10–50 mA input signal?
No. The “I” in the model code BI2 designates the 4–20 mA input range with 170 Ω impedance. If your system outputs 10–50 mA, you need a different model code (the “H” suffix variants handle 10–50 mA with 27 Ω impedance).Does this converter need external power?
No. The E69F is a passive I/P converter — it draws its operating energy from the 4–20 mA current loop itself. You don’t need a separate power supply. Just make sure your loop has enough voltage headroom to drive the 170 Ω internal impedance plus your wiring resistance.What air supply pressure do I need?
For the standard 3–15 psi output range, you need a clean, dry air supply of at least 20 psi (ideally 25–30 psi) at the 1/4 NPT inlet. If your supply pressure is marginal, the converter will clip at the high end and your valve won’t reach full travel.My output is stuck at full pressure. What’s wrong?
Most likely cause: contaminated air supply has gummed up the nozzle/flapper mechanism. Shut off the air, disconnect the supply line, and blow clean dry air backward through the unit. If that doesn’t clear it, the internal mechanism is fouled and the unit needs bench service or replacement.Is the E69F-BI2 explosion-proof?
No. The “-B” housing is weatherproof (IEC IP65 / NEMA 4) with a bolted cover. If you need explosion-proof certification for a hazardous area, you need the “-T” housing variant with a threaded cover and the appropriate electrical certification suffix (e.g., “-J” for integral explosion-proof junction box).How do I know if my old unit is direct or reverse acting?
Direct action means increasing input current produces increasing output pressure. Reverse action is the opposite. Check the data plate — if it says “direct,” a standard BI2 replacement will work. If it says “reverse,” you need a reverse-acting variant, which uses a different model code suffix.
