Foxboro RH916RB Dual-Input Panel-Mount Recorder with RS-485

Technical Specifications:

• Input Channels: 2 universal inputs (independent configuration)
• Input Types: Thermocouple (J, K, T, E, S, R, B); RTD (Pt100, Pt1000, Cu50, Cu100); 4–20 mA; 0–10 V; 1–5 V
• Display: Dual-line 6-digit red LED, 14 mm digits
• Recording Memory: 8000 data points per channel with date/time stamp
• Recording Interval: 1 second to 60 seconds (user-configurable)
• Communication: RS-485, Modbus RTU, 9600–38400 baud
• Alarm Outputs: 2 SPDT relays per channel, 250 V AC / 30 V DC, 3 A
• Retransmission: Isolated 4–20 mA per channel
• Power Supply: 85–265 V AC / 90–300 V DC / 24 V DC
• Operating Temperature: -10°C to +55°C (+14°F to +131°F)
• Protection Rating: IP65 front panel
• Dimensions: 96 mm x 96 mm x 92 mm (W x H x D)
• Cutout Size: 92 mm x 92 mm
• Weight: Approximately 450 grams

Functional Features:

• Extended Trend Recording: 8000 points per channel with full date and time stamp
• Dual Display: Simultaneous real-time display of both channels
• Data Download: Trend data downloadable via RS-485 Modbus to host system
• Alarm with Latching: Relays latch in alarm state until manually reset
• Max/Min/Avg: Per-channel statistical display

Material Composition:

• Front Bezel: Flame-retardant ABS, matte black
• Housing: Polycarbonate (Lexan), IP65 gasket seal
• Display Window: Optical-grade polycarbonate, anti-reflective
• Terminals: Phosphor bronze, nickel-plated screw terminals

Structural Characteristics:

• Form Factor: 96 x 96 mm panel-mount (1/4 DIN)
• Keypad: 6-button membrane with channel toggle and menu navigation
• Communication Connector: RJ-11 modular jack, rear-mounted
• Memory Type: Non-volatile EEPROM — data retained during power loss

Working Principle:
Each channel’s signal is digitized by a dedicated 24-bit ADC. The microcontroller applies range-specific linearization and stores the value in EEPROM at the configured recording interval along with a real-time clock timestamp. The current value is displayed on the LED. The RS-485 interface responds to Modbus function codes to read current values, alarm status, and download recorded trend data. Alarm comparators drive SPDT relays independently per channel.

Advantages / Highlights:

• 8000-point non-volatile memory provides extensive trend history without external recorder
• Dual-channel recording captures two process variables simultaneously
• Modbus RTU enables direct integration with Foxboro I/A and third-party DCS/SCADA
• Latching alarms ensure alarm conditions are not missed during transient events
• IP65 front panel suitable for washdown and outdoor panel applications

Applicable Industries:

• Oil and Gas (production, refining, transportation)
• Chemical Processing
• Power Plants (thermal, hydro, nuclear)
• Pharmaceutical Manufacturing
• Food and Beverage

Installation Requirements:

• Cut 92 mm x 92 mm panel opening
• Mount with snap-in clips and IP65 gasket
• Wire Ch1 input to Ch1 terminals, Ch2 input to Ch2 terminals
• Connect RS-485 to A, B, GND — use shielded twisted pair cable
• Provide 85–265 V AC or 24 V DC power
• Set Modbus address via DIP switches (default address typically 1)
• Install 120 Ω termination at bus endpoints

Usage Precautions:

• Do not power cycle during trend recording — may corrupt EEPROM data
• Verify recording interval matches application requirements (shorter interval = faster memory fill)
• Maximum 8000 points per channel — configure recording interval accordingly
• Do not apply > 50 V DC to mA/V input terminals
• Cold junction compensation is automatic — do not disconnect CJC sensor