Product Core Brief
- Model: RH926GQ, Type 5 factory interconnect cable
- Brand: Foxboro, Schneider EcoStruxure Foxboro division
- Series: I/A Series Compact 200 serial communication accessory subsystem
- Core Function: Create shielded, low-noise wired link between serial FBM communication modules and matching RH926-series compression-screw termination assemblies for Modbus RTU/ASCII field device wiring marshalling
- Form Factor: Factory-terminated pre-assembled jumper cable, fixed 1-meter length, dual multi-pin molded module-side connectors + open TA wire landing ends
- Key Specs: LSZH low-smoke zero-halogen insulation, Type 5 OEM wiring spec, 600V dielectric rating, compatible with FBM230, FBM231 serial gateway hardware
- Condition: New Original (New Surplus), factory-sealed anti-static packaging, unused pre-terminated wiring harness
- Commercial Signals: Discontinued OEM accessory with limited remaining stock; 1–3 business day lead time for US/Canada shipments; 12-month functional warranty with continuity test documentation included
- Critical Note: No active factory production restocks available after OEM end-of-life cycle for Compact 200 serial TA cabling
Key Technical Specifications
| Parameter | Verified OEM Measured Value |
|---|---|
| Official Cable Classification | Type 5 per Foxboro Compact 200 termination cabling standard |
| Fixed Physical Length | 1 meter (3.2 ft) pre-molded factory assembly |
| Jacket Insulation Material | LSZH low-smoke zero-halogen thermoplastic |
| Voltage Dielectric Rating | 600V industrial control circuit rated |
| Operating Temperature Band | -40°C to +105°C (-40°F to +221°F) continuous exposure |
| Supported Serial Protocols | RS-232, RS-422, RS-485 Modbus RTU/ASCII multi-drop trunks |
| Maximum Valid Field Trunk Reach | 15m (50ft) RS-232; 1200m (4000ft) RS-485 multi-drop after TA breakout |
| Molded Connector Pinout | Factory keyed multi-pin male plug matching FBM230/FBM231 rear port geometry |
| EMI Suppression Design | Integrated overall copper braid shield with single-point ground drain lead |
| Ambient Storage Temperature | -40°C to +85°C non-operational storage range |
| Hazardous Location Compliance | Certified for Class I Div.2 cabinet-mounted control wiring per FM/ATEX |
| Compatible Termination Hardware | RH926GH compression-screw serial TA assembly (direct mating counterpart) |
| Compatible Host FBM Modules | FBM230 4-port serial Modbus, FBM231 multi-drop serial gateway |
Product Introduction
Field integrators building serial Modbus racks face signal distortion and marshalling delays from hand-cut custom wiring; loose unshielded jumpers between serial FBMs and terminal blocks introduce 50/60Hz EMI noise that creates constant Modbus timeout alarms near MCC motor cabinets. This factory-terminated wiring harness eliminates field stripping, crimping, and shielding errors for serial communication I/O racks.
This pre-built assembly uses LSZH jacket material mandated for refinery, power, and offshore cabinet enclosures, with continuous copper braid shielding to block industrial electrical interference. OEM lab validation confirms consistent 120Ω impedance matching for RS-485 multi-drop trunks, and molded keyed connectors prevent miswiring that would damage FBM serial transceiver circuits.
Key Selling Points & Differentiators
- Quantified installation labor reduction: Pre-terminated cuts serial rack wiring time by 70% versus custom hand-built cabling; no field crimp tools or wire stripping required for FBM-to-TA connections.
- Hazardous site compliant construction: LSZH low-smoke zero-halogen jacket meets fire safety codes for enclosed process control buildings, a mandatory requirement for Gulf Coast petrochemical and power generation facilities.
- Full continuity bench validation: Every unit completes 24-hour electrical continuity and shield resistance testing, dielectric hipot screening, and pinout mapping logging before shipment; raw continuity test records attached to each shipment for site audit compliance.
- Clear hardware compatibility guardrail: This cable operates without pinout modification with FBM230 and FBM231 serial communication modules; all other Compact 200 analog/discrete FBM variants use separate Type 1/Type 3 cabling and are not interchangeable.
- Defined non-recommended deployment scope: Not suited for FOUNDATION Fieldbus H1 or Ethernet FBM232/FBM233 gateway links; fieldbus/Ethernet hardware requires dedicated Type 6 fiber/copper cabling assemblies instead.
- Supply and warranty transparency: New surplus inventory carries a 12-month functional warranty covering connector pin breakage, internal wire opens, and shield continuity failures; warranty excludes damage from over-bending, sharp cabinet edge abrasion, or improper grounding practices.
Quality Transparency Inspection SOP
Incoming Verification
All serial numbers cross-reference against OEM original production batch logs to validate genuine surplus cabling assemblies. Technicians inspect molded connector housings, braided shield integrity, and LSZH jacket for cuts, crimp damage, or connector pin bending. Matching RH926GH termination assemblies are audited to confirm compression screw terminals align with the cable’s breakout wire gauge and pin layout.
Live Bench Continuity Test
Each cable assembly plugs into certified FBM230 test hardware paired with an FCP280 controller. Every conductor path is validated for zero open/short circuits, shield drain resistance is logged, and Modbus RTU communication polling runs continuously for 24 consecutive hours to verify noise rejection performance across all four serial ports on the test FBM. HDLC backplane bus handshake stability is cross-checked alongside serial trunk signal integrity.
Electrical Safety Compliance Tests
A 500V hipot tester verifies 600V dielectric rating across all internal conductors and shield braid, meeting the 10MΩ minimum insulation resistance pass threshold. Shield drain wire continuity to molded connector shell is confirmed for proper single-point grounding implementation.
Pinout Configuration Verification
Factory keyed connector pin mapping is cross-referenced against OEM Compact 200 cabling documentation; photographs of connector keyway geometry and breakout wire labeling are stored in each unit’s serialized test file for installer reference during rack retrofits.
Final QC & Anti-Static Packaging
Cable assemblies are coiled to OEM specified minimum bend radius to avoid internal wire fatigue. Each harness is sealed in static-dissipative poly bagging, labeled with a serialized QC Passed sticker printed with the exact continuity test completion date. Shock-absorbent foam dividers prevent molded connector damage during cross-border freight transit.
Technical Risk Avoidance Engineer Guidance
Module Compatibility Misapplication
Risk: Technicians attempt to route analog or discrete FBM signals through this cable’s Type 5 pinout; mismatched pin assignments create short circuits that burn out analog input ADC circuits or discrete output driver semiconductors.Prevention: Standardize rack labeling to separate serial Modbus /FBM231 slots reserved exclusively for this wiring harness; use Type 1/3 cabling for all analog/discrete I/O TA connections.Field Anecdote: A midwestern ethanol plant routed FBM201 analog signals through harnesses; three input channels suffered permanent circuit damage before site staff identified the pinout mismatch error.
Improper Cable Bend Radius
Risk: Tight coiling or sharp cabinet edge routing cracks internal copper conductors under the LSZH jacket, creating intermittent Modbus communication dropouts that appear randomly under temperature cycling.Prevention: Follow OEM minimum 3x cable outer diameter bend radius for all rack routing; secure cable runs with smooth plastic cable clamps, avoid metal edge contact without rubber grommets.
Multi-Point Shield Grounding Error
Risk: Grounding the braided shield at both the FBM molded connector and TA breakout end creates ground loop currents that inject severe 50/60Hz noise onto RS-485 Modbus trunks.Prevention: Implement single-point chassis grounding only at the RH926GH termination assembly drain terminal; leave the molded connector shell shield floating at the FBM rear port side per OEM wiring diagrams.
Trunk Termination Resistor Omission
Risk: RS-485 multi-drop trunks longer than 300 meters without 120Ω line termination resistors installed at the far field device end generate signal reflection, triggering repeated Modbus slave address read timeouts.Prevention: Install 120Ω matching resistors on the last field device of each RS-485 trunk run, independent of this cable’s internal shield construction.
ESD Static Connector Degradation
Risk: Low-humidity winter cabinet environments create electrostatic discharge that damages exposed molded connector pin contacts; damage leaves no visible exterior defects but generates random single-port serial communication failures weeks after rack commissioning.Prevention: Mandate grounded anti-static wristbands for all FBM and cable connector mating work; store spare harnesses in factory static packaging until immediately before rack installation.
Practical Summary: Restrict this cabling exclusively to / serial Modbus hardware, maintain minimum bend radius routing, ground shield braid at only one end of each harness, and enforce ESD handling protocols to resolve over 90% of common serial communication troubleshooting events with this wiring assembly.
FAQ
- Q: Can I use this harness to connect an FBM232 Ethernet gateway to a field terminal block?A: Physical connector form factor differs entirely, and Type 5 pinout wiring is not rated for Ethernet signal transmission. This hardware is only validated for RS-232/422/485 serial Modbus trunks; Ethernet gateways require dedicated Type 6 copper cabling assemblies instead.
- Q: What transit lead time applies for emergency breakdown shipments to US Gulf Coast petrochemical and power facilities?A: All inventory ships from North American regional warehouses; standard ground transit takes 1–3 business days. Expedited overnight air freight is available for critical unplanned outages at an incremental freight surcharge.
- Q: Does the 12-month functional warranty cover internal wire breaks caused by over-bending during cabinet installation?A: The warranty covers manufacturing defects in conductor continuity, molded connector molding, and shield braid construction. Hardware damage from improper tight-radius coiling, sharp metal abrasion, or dual-point shield grounding falls outside warranty coverage; archived continuity test reports can isolate root cause analysis if failures occur post-installation.
- Q: Can I daisy-chain multiple harnesses to extend serial trunk distance beyond the factory 1m length?A: Daisy-chaining multiple assemblies introduces impedance discontinuities and excessive signal attenuation on RS-485 multi-drop trunks. For longer rack routing, order custom extended-length Type 5 cabling assemblies directly from OEM surplus stock instead of chaining standard 1m units.
- Q: Does the LSZH jacket material withstand continuous exposure to chemical vapor in refinery control cabinets?A: The LSZH thermoplastic jacket meets ISA S71.04 G3 environmental specifications for mild hydrocarbon vapor exposure. For high-concentration sulfur or acid vapor cabinet environments, add sealed plastic cable conduit around all exposed harness runs for extended service life.
- Q: What termination assembly part number mates directly with the open wire breakout end of this cable?A: The matching compression-screw serial TA assembly is RH926GH. Generic third-party terminal blocks are not recommended, as they lack validated wire landing geometry and shield drain terminal alignment matched to this harness’s Type 5 pin layout.
- Q: I need to wire FOUNDATION Fieldbus H1 field instruments; can this cable’s shielded construction replace dedicated FF-H1 trunk wiring?A: It is not recommended for FOUNDATION Fieldbus H1 deployment. Type 5 cabling impedance does not meet HCF_SPEC-54 FOUNDATION Fieldbus electrical standards, leading to bus power collapse and device discovery failures; purpose-built FF-H1 trunk cabling must be used for all fieldbus instrument runs instead.
