Foxboro RH916MZ Dual-Input Panel-Mount Indicator with Communication

Technical Specifications:

• Input Channels: 2 independent universal inputs (Ch1 and Ch2)
• Input Types (per channel): Type J, K, T, E, S, R, B TC; Pt100, Pt1000 RTD; 4–20 mA; 0–10 V; 1–5 V
• Display: Dual-line 6-digit red LED, 14 mm digits, 100,000 count per line
• Accuracy: ±0.1% of span (mA/V); ±0.5% of span (TC/RTD)
• Communication: RS-485, Modbus RTU, 9600/19200/38400 baud (configurable)
• Alarm Outputs: 2 SPDT relays per channel (4 total), 250 V AC / 30 V DC, 3 A
• Retransmission: Isolated 4–20 mA output per channel (optional)
• 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 90 mm (W x H x D)
• Cutout Size: 92 mm x 92 mm
• Weight: Approximately 420 grams

Functional Features:

• Dual Independent Channels: Simultaneously monitor two process variables with independent configuration
• Modbus RTU Communication: Enables integration with SCADA, DCS, and PLC systems
• 4 Alarm Relays: 2 per channel with independent high/low setpoints and hysteresis
• Peak/Valley Hold: Per-channel peak and valley capture
• 24 V Loop Power: Provides loop power to 2-wire transmitters on each channel (max 600 Ω)

Material Composition:

• Front Bezel: Flame-retardant ABS, black matte finish
• Housing: Polycarbonate (Lexan), IP65 gasket-sealed
• Display: High-brightness red LED, optical-grade polycarbonate window
• Terminals: Phosphor bronze, nickel-plated

Structural Characteristics:

• Form Factor: 96 x 96 mm panel-mount (1/4 DIN)
• Display Layout: Top line = Channel 1, Bottom line = Channel 2
• Keypad: 6-button membrane keypad with navigation between channels
• Communication Port: RJ-11 jack on rear panel (terminals A, B, GND)

Working Principle:
Each input channel has an independent 24-bit ADC and microcontroller. The signals are digitized, linearized (for TC/RTD), and scaled to engineering units. Channel 1 is displayed on the top LED line; Channel 2 on the bottom line. The Modbus RTU master polls the device via RS-485 to read process values, alarm status, and setpoints. Each channel has an independent alarm comparator driving its own SPDT relays.

Advantages / Highlights:

• Dual-channel monitoring in a single 96 x 96 mm instrument saves panel space
• Modbus RTU communication enables seamless DCS/SCADA integration
• 4 independent alarm relays provide comprehensive protection
• Per-channel loop power eliminates external power supplies for 2-wire transmitters
• Dual-line display allows simultaneous observation of two variables

Applicable Industries:

• Oil and Gas (refineries, pipelines)
• Chemical and Petrochemical
• Power Generation and Distribution
• Water and Wastewater
• Mining

Installation Requirements:

• Cut 92 mm x 92 mm panel opening
• Mount with gasket-sealed snap-in clips
• Connect Ch1 field wiring to terminals Ch1-IN+/-
• Connect Ch2 field wiring to terminals Ch2-IN+/-
• RS-485 bus connects to A, B, GND terminals (daisy-chain topology, max 32 devices)
• Power connections to L, N (AC) or +, – (DC)
• Ensure 120 Ω termination resistor at each end of RS-485 bus

Usage Precautions:

• Set correct Modbus slave address (1–247) via DIP switches — no two devices on same bus may share an address
• Do not mix AC and DC power on the same unit
• Maximum RS-485 cable length is 1200 meters at 9600 baud
• Verify input type per channel before energizing — mismatched input causes display error
• Do not exceed 600 Ω total loop resistance per channel