Description
Foxboro E69F-BI2-S | Current-to-Pneumatic Converter, In Stock
Architect’s Product Breakdown
The Foxboro E69F-BI2-S builds upon the standard E69F-BI2 architecture by incorporating the -S optional selection: an integral miniature junction box. This model receives a standard analog current signal (such as 4-20 mA) from an electronic control system or PLC and utilizes an internal galvanometric motor and pneumatic relay module to regulate clean instrument air into an exact proportional output range (such as 3-15 psi).
The addition of the junction box suffix (-S) provides a dedicated, protected terminal housing for field wiring termination directly on the device, simplifying conduit entry and electrical hookups in standard industrial environments. Because this unit is heavily integrated into legacy process loops across chemical, refining, and power generation sectors, matching the precise -S suffix configuration is essential when replacing field units to ensure physical wiring and connection layouts match seamlessly.

E69F-BI2-S
Key Technical Specifications
| Parameter | Specification |
| Series | Foxboro E69F Field-Mounted I/P Converter |
| Model / Part Number | E69F-BI2-S |
| Enclosure Type (B) | Bolted cover – weatherproof design for general industrial applications |
| Input Signal Range (I) | 4 to 20 mA dc (direct or reverse action selectable; ~170 Ω impedance) |
| Output Signal (2) | 3 to 15 psi (20 to 100 kPa / 0.2 to 1.0 bar) |
| Optional Feature (-S) | Integral miniature junction box for direct field wiring termination |
| Air Supply Requirements | Clean, dry, oil-free instrument air |
| Mounting Options | Surface, valve yoke, or vertical 2-inch (DN 50) pipe mount |
Field Engineer’s Pitfall Guide
- WARNING: Moisture Contamination in Junction Box. Failing to properly seal the conduit entry feeding the
-Sminiature junction box allows ambient condensation or washdown moisture to run down into the terminal terminals, causing signal grounding faults. - WARNING: Unfiltered Instrument Air Supply. Introducing oil, water, or particulate matter from plant air headers will foul the internal pneumatic relay and restrictor, resulting in calibration drift or output lockup.
- WARNING: Calibration Interaction. Adjusting the zero potentiometer changes the baseline output, but altering span settings requires a subsequent zero check to maintain precise 4-20mA to 3-15psi tracking linearity.
- Field Anecdote: I remember an automation technician spending hours troubleshooting an erratic control loop because moisture entered through an unsealed conduit plug on the unit’s junction box, corroding the internal input signal landing terminals.
QA & Testing SOP
- Visual & Origin Verification: Inspect the die-cast housing, junction box cover gasket, and pneumatic ports for structural cracks, thread damage, or corrosion, and verify original Foxboro nameplate details.
- Live Test Bench Environment: Mount the converter to a pneumatic test bench, connect the signal wiring inside the
-Sjunction box to a calibrated 4-20mA source, and supply regulated instrument air. - Calibration & Performance Testing: Step the input current through 0%, 50%, and 100% ranges, measuring the pneumatic output against a high-accuracy digital pressure gauge to verify linearity and check for hysteresis.
- Anti-Static & Protective Packaging: Plug all pneumatic ports and pack the unit in high-density foam cushioning to protect external fittings and housing enclosures during shipping.
Technical FAQ
What does the “-S” suffix explicitly designate on this model?
The -S suffix indicates that the unit is equipped with an integral miniature junction box, providing a clean enclosure for field wiring terminations.
Can the E69F-BI2-S be used in hazardous explosion-proof areas?
The baseline “B” bolted cover enclosure is weatherproof for non-explosionproof applications. For hazardous locations, specific explosion-proof versions (such as the “T” threaded cover designs) are required.
What is the recommended replacement if this legacy unit fails permanently?
Schneider Electric/Foxboro typically points toward modern IP26 Series current-to-pneumatic converters as direct functional replacements for obsolete E69F units.
Does the unit require an external power supply separate from the signal loop?
No. The -BI2-S is loop-powered, deriving its operating energy directly from the incoming 4-20 mA control current loop.


