Description
Foxboro FBM218 RH922VW Product Page
Product Overview
The Foxboro FBM218 RH922VW is a HART communication analog output module designed for Foxboro I/A Series and Foxboro Evo distributed control systems. It provides eight electrically isolated output channels, each capable of delivering a 0–20 mA current signal. A channel can be used for a conventional analog output or for a 4–20 mA signal with HART digital communication superimposed. This allows the control system to command compatible field devices while exchanging supported digital information with smart instruments over the same current loop.
The module supports HART versions 5, 6, and 7 and communicates with compatible field devices using point-to-point, asynchronous, half-duplex signaling at 1200 baud. Its dedicated FSK modem on each channel enables bidirectional communication. The module can support up to two digital messages per second from each field device, subject to system loading and configuration. Analog output accuracy is specified at ±0.05% of span between 4 mA and 20 mA, with 13-bit resolution and a maximum load of 750 ohms. Each output channel has galvanic isolation from the other channels, ground, and module logic, helping limit electrical interaction between field circuits.
For plant maintenance teams, the Foxboro FBM218 RH922VW is particularly relevant to applications where smart valve positioners and other HART-capable actuators must remain connected to an established DCS. Two FBM218 modules can operate as a redundant pair, with one designated Master and the other Tracker. When a module fault is detected, the faulty module’s output is driven to 0 mA so the healthy module can continue supplying the loop current, provided the system has been configured for the documented redundancy behavior. Replacement planning should include the RH916QD redundant adapter, RH926SP termination assembly, termination cable, field-loop load, and configured fail-safe settings. The part number identifies the module, not the complete installation kit.
Product Introduction — Field Engineering Focus
A failed analog output can leave a valve positioner without the intended command, while a loss of HART communication can remove access to useful field-device diagnostics. The Foxboro FBM218 RH922VW combines eight isolated analog outputs with HART communication, supporting compatible current-loop actuators and smart positioners in a Foxboro DCS.
For replacement work, verify the redundant-module arrangement, termination hardware, loop resistance, and output fail-safe configuration. Test both the analog command and HART communication before returning affected control loops to service.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Model | FBM218 |
| Part number | RH922VW |
| Previous part number | P0922VW |
| Manufacturer | Foxboro / Schneider Electric |
| Product type | HART communication redundant output module |
| Module family | Standard 200 Series FBM |
| Output channels | 8 isolated channels |
| Output range | 0–20 mA |
| Typical process signal | 4–20 mA |
| HART versions | 5, 6, and 7 |
| HART communication | Point-to-point, master/slave, asynchronous, half-duplex |
| HART baud rate | 1200 baud |
| HART message rate | Up to 2 messages per second per field device |
| Analog output accuracy | ±0.05% of span, 4–20 mA |
| Output resolution | 13 bits |
| Maximum output load | 750 Ω |
| Maximum output rate of change | 20 mA in 60 ms |
| Channel isolation | Galvanic isolation between channels, ground, and module logic |
| Module power supply | 24 VDC, +5%/−10% |
| Maximum power consumption | 7 W |
| Maximum heat dissipation | 5 W |
| Module fieldbus | Redundant 2 Mbps HDLC |
| Redundancy adapter | RH916QD |
| Termination assembly | RH926SP |
| Termination cable length | Up to 30 m, depending on cable type |
| Operating temperature | −20°C to +70°C |
| Storage temperature | −40°C to +70°C |
| Relative humidity | 5–95%, non-condensing |
| Contamination rating | Suitable for ISA S71.04 Class G3 environments when properly installed |
| Mounting | Standard 200 Series baseplate; DIN rail or 19-inch rack with mounting kit |
| Dimensions | 102 mm high; 114 mm including mounting lugs × 45 mm wide × 104 mm deep |
| Module weight | Approximately 284 g |
FBM218 RH922VW
Related Products
- FBM215 RH922VU: An eight-channel HART output module in the same general product family, but with different redundancy characteristics. Confirm the exact system requirements before considering it as an alternative.
- FBM216b RH927AJ: An eight-channel redundant-ready HART input module for reading field signals rather than driving output loops.
- FBM214b RH927AH: An eight-channel HART input module with a different input-focused role.
- FBM244 RH927AK: A four-input/four-output analog I/O module with HART support; it has a different channel arrangement.
- RH916QD: Redundant adapter used to connect a pair of modules to a common termination assembly.
- RH926SP: Compression-type termination assembly documented for output wiring.
- RH916DA: 0.5 m polyurethane termination cable option.
- RH916DC: 3 m polyurethane termination cable option.
- RH928AA: 0.5 m LSZH termination cable option.
- RH928AD: 3 m LSZH termination cable option.
These components serve different signal or installation roles. Confirm the exact module generation, cable length, termination hardware, and system configuration before ordering related parts.
Frequently Asked Questions
Q1. What is the Foxboro RH922VW used for?
It provides eight analog output channels for compatible Foxboro DCS installations. Each channel can deliver a current command to a field device and support HART communication when used with a compatible instrument.
Q2. Is the an analog input or output module?
It is an analog output module. For HART input applications, a model such as FBM216b RH927AJ may be more appropriate, subject to the required system configuration.
Q3. Can the communicate with HART 7 devices?
Yes. The official product specification lists compatibility with HART versions 5, 6, and 7. Device-specific functions still depend on the instrument’s implementation and the available DCS configuration tools.
Q4. Can I hot-swap the ?
The manufacturer states that the module can be removed or replaced without disconnecting field termination cabling, power, or communications cabling. That physical capability does not automatically authorize replacement during live process operation. Follow the site’s approved maintenance procedure and confirm the effect on affected output loops before removal.
Q5. How does redundancy work with the ?
A redundant pair consists of two adjacent modules connected through the RH916QD redundant adapter to a common termination assembly. One module acts as Master and the other as Tracker. If a detectable module fault occurs, the faulty module’s output is driven to 0 mA, allowing the healthy module to maintain the loop current under the documented configuration.
Q6. Which termination assembly is specified for ?
The Schneider Electric specification lists RH926SP as the compression-type termination assembly for the . Confirm the cable part number and required length against the installation drawings before ordering.
Q7. What is the maximum permitted output load?
The specified maximum output load is 750 Ω. The actual loop budget must include field-device impedance, wiring resistance, barriers, and other series components. If the total resistance exceeds the available compliance capability, the output may not reach the commanded current.
Q8. What should procurement verify when buying a refurbished ?
Confirm the label, module condition, connector integrity, test evidence, warranty, and return terms. For a redundant installation, also verify the RH916QD adapter, RH926SP termination assembly, and correct termination cable. Ask for evidence that all eight output channels and HART communication have been tested rather than relying solely on a power-up check.
