Description
FOXBORO RH916DD Digital Input Module
Technical Specifications Model: RH916DD Brand: Foxboro Power Supply: DCS backplane bus power Input Type: Dry contact digital input Communication: DCS internal backplane bus Operating Temperature: 0 ℃ ~ +60 ℃ Storage Temperature: -40 ℃ ~ +85 ℃ Relative Humidity: 5% ~ 90%, non-condensing Mounting: DCS rack slot installation Protection Grade: IP20 Input Filter: Built-in signal debounce filter
Functional Features Multi-channel dry contact digital input collects status signal from field limit switches and auxiliary contacts. Built-in hardware debounce filter eliminates contact bounce interference of mechanical switches. Per-channel self-diagnosis monitors input channel hardware state. Backplane bus transmits collected digital status data to DCS controller. Front panel LED indicators display power status, running status and each channel signal state. Supports hot swap operation in compatible Foxboro DCS rack configuration. EMC protection circuit suppresses industrial electromagnetic interference. Channel status data can be displayed on DCS operator station in real time.
Application Scenarios Power plant auxiliary equipment status monitoring, chemical plant valve position feedback, oil & gas pipeline equipment contact signal collection, refining plant interlock system signal acquisition, water treatment plant pump and valve status monitoring.
Performance Parameters Debounce filter eliminates mechanical contact bounce signal and prevents false status trigger. Input channel reliably detects contact open and closed state under industrial interference environment. Self-diagnosis circuit detects module hardware abnormality and uploads fault alarm. Backplane bus keeps stable communication with DCS controller under rated operating temperature. LED indicators synchronously display real-time channel signal status. Hot swap allows module replacement without shutdown of whole DCS rack.
Material Composition Housing: Flame-retardant plastic front panel and metal shielding frame. Main PCB: FR4 multi-layer printed circuit board with conformal protective coating. Core Electronic Components: Bus interface chip, digital input sampling circuit, debounce filter chip, EMC protection components, non-volatile memory. Connector: Gold-plated backplane edge connector and field signal screw terminals. Indicator Components: LED channel status indicators on front panel. Fasteners: Stainless steel screws and metal fixing brackets.
Structural Features Standard DCS rack card mechanical structure for Foxboro control rack installation. Front panel equipped with LED indicators and module marking. Rear gold-plated edge connector connects with DCS rack backplane for power and bus communication. Screw terminals for field contact wiring are arranged on module front or rear side. Metal shielding frame reduces electromagnetic interference. Internal circuit separates field input signal circuit and DCS digital bus circuit.
Working Principle RH916DD obtains DC working power and DCS bus signal from DCS rack backplane. Field dry contact signals are connected to module input screw terminals. When field contact closes or opens, input sampling circuit captures contact state. Built-in debounce filter removes transient bounce signal of mechanical contact. The sampled digital signal is sent to onboard bus interface chip, and status data is transmitted to DCS controller through backplane bus. Self-diagnosis circuit continuously monitors module hardware and channel circuit state. If hardware fault occurs, fault LED activates and alarm information is uploaded to DCS operator station.
Installation Requirements Power off DCS rack if hot swap is not allowed by system configuration before module installation. Insert RH916DD module into empty DCS rack slot, lock front panel fasteners. Connect field dry contact wiring to module screw terminals according to wiring diagram. Complete module identification and channel configuration in Foxboro DCS configuration software. Power on rack and verify channel signal acquisition function. Keep ventilation space of DCS rack unobstructed. Separate field signal cables from high-power AC cables.
Usage Precautions Module protection grade is IP20, install only inside closed control cabinet. Do not apply external voltage to dry contact input terminals. Use shielded twisted pair cable for long-distance field contact wiring. Do not operate in environment with condensation, corrosive gas or conductive dust. Do not disassemble module housing without professional authorization. Check terminal screw tightness during regular maintenance. Cut off field equipment power before modifying field contact wiring.
