# Binary Input Module - Quick Reference SSO **Device Type:** Binary Input - Digital Status Monitoring **Signal:** Dry contact (NO/NC) or voltage input **Power:** 24VAC/VDC (for controller input) or dry contact **Version:** 1.0 | **Date:** Dec 2025 --- ## DEVICE OVERVIEW **Common Models:** - Standalone binary input modules (part of controller), Functional Devices RIB relay with status, Dry contact monitors **Used For:** Proof of operation (fans, pumps, dampers), status monitoring (filter status, flow switches, door contacts), alarm monitoring (fire alarm, freeze stat, high temp), end switches, limit switches **Specifications:** - **Input Types:** * Dry contact (most common) - voltage-free switch closure * Wet contact - voltage present on input * Voltage sensing - monitors presence of voltage (24V-277V) - **Contact Types Monitored:** * NO (Normally Open) - closes when activated * NC (Normally Closed) - opens when activated - **Wire Type:** 18AWG minimum - **Wiring:** 2-wire typical (digital input + common) **Environment:** Varies by monitored device --- ## SAFETY - PPE REQUIRED - ☑ Safety glasses (ANSI Z87.1) - ☑ Work gloves - ☑ **Insulated gloves if monitoring voltage >50V** - ☑ Hard hat (if in mechanical room) ### HAZARDS - ⚠️ **VOLTAGE SENSING APPLICATIONS** - May involve line voltage (120V-277V) - ⚠️ **MECHANICAL EQUIPMENT** - Monitored devices may have moving parts - ⚠️ **Warning:** Binary input indicates electrical status, not mechanical safety ### LOCKOUT/TAGOUT - [ ] **Required if wiring to energized equipment** - [ ] **Required if accessing equipment with moving parts** - [ ] NOT required for low-voltage dry contacts - [ ] Verify voltage type before working --- ## INSTALLATION CHECKLIST ### TOOLS NEEDED - Wire strippers (18AWG) - Screwdrivers - Multimeter (DMM) - Continuity tester - Label maker ### MATERIALS - Wire (18AWG) - Wire nuts or terminal blocks - Binary input device (if external module) - Status switch/relay (if monitoring equipment without built-in contacts) ### PRE-INSTALL - [ ] Identify device/equipment to monitor - [ ] Determine contact type available (NO or NC) - [ ] Verify contact rating if switching current - [ ] Confirm controller has available binary input point - [ ] Review wiring diagram ### INSTALL STEPS - DRY CONTACT MONITORING **MOST COMMON: Monitoring Auxiliary Contacts** 1. **Identify source contacts:** - Pump/fan starter: Auxiliary contacts (typically NO) - Motor starter: Status contacts - Relay: Extra contacts if available - End switch: Mechanical position switch - Flow switch: Paddle or differential pressure switch - Pressure switch: High/low pressure cutout - Thermostat: Heat/cool status contacts 2. **Determine contact state:** - **NO (Normally Open):** Open when off, closes when on * Use for: Proof of operation (pump running = closed contact) - **NC (Normally Closed):** Closed when off, opens when on * Use for: Alarm monitoring (fire alarm = opens when tripped) 3. **Connect to controller binary input:** - **2-wire connection (most common):** * Wire 1: From contact terminal 1 → Controller BI terminal * Wire 2: From contact terminal 2 → Controller common - **Polarity doesn't matter** for dry contacts - Tighten terminals: 7-9 in-lbs - Route wiring away from high-voltage cables 4. **Configure controller input:** - Set as NO (normal state = open) or NC (normal state = closed) - Example: Motor status NO contact: * Motor OFF: Contact open = Binary input FALSE/0 * Motor ON: Contact closed = Binary input TRUE/1 5. **Label wiring:** - Example: "PUMP-1-STATUS" or "FILTER-ALARM" - Label at both controller and device ends ### INSTALL STEPS - VOLTAGE SENSING **For monitoring presence of voltage (line voltage proof):** 1. **Select voltage sensing module:** - Must be rated for monitored voltage (24V, 120V, 208V, 277V) - Example: Functional Devices RIBS voltage sensing relay 2. **Connect to monitored circuit:** - **INPUT side (voltage to monitor):** * Connect voltage sensing module to circuit being monitored * Follow module wiring diagram * **Verify voltage rating before connecting** - **OUTPUT side (dry contacts to controller):** * Connect module output contacts to controller binary input * Typically NO contacts (closed when voltage present) 3. **Configuration:** - Controller sees dry contact status - Voltage present = contact closed = TRUE - Voltage absent = contact open = FALSE ### POST-INSTALL - [ ] Wiring connections tight - [ ] Correct contact type confirmed (NO vs NC) - [ ] Labels applied at both ends - [ ] Controller input configured correctly - [ ] Work area cleaned - [ ] Photos taken --- ## EXPECTED READINGS ### PRE-POWER (Equipment OFF) **Monitoring NO (Normally Open) Contact:** - **Continuity:** Open circuit (infinite resistance) - **Controller Reading:** FALSE / 0 / OFF / Inactive **Monitoring NC (Normally Closed) Contact:** - **Continuity:** Closed (<1 ohm) - **Controller Reading:** TRUE / 1 / ON / Active ### POWER-UP (Equipment ON) **NO Contact (Proof of Operation):** | Equipment State | Contact State | Controller Reading | |----------------|---------------|-------------------| | OFF | Open | FALSE / 0 | | ON | Closed | TRUE / 1 | **NC Contact (Alarm Monitoring):** | Equipment State | Contact State | Controller Reading | |----------------|---------------|-------------------| | Normal | Closed | TRUE / 1 | | Alarm | Open | FALSE / 0 | **Controller Configuration:** - Set controller to expect NO or NC - **Alarm on Change:** Trigger alarm when state changes - **Alarm on State:** Trigger alarm when specific state (TRUE or FALSE) --- ## PROOF OUT TESTS ### TEST 1: Contact Continuity Test (Power OFF) - **Do:** Measure continuity across contact with multimeter - **Expect:** * NO contact: Open (infinite ohms) when de-energized * NC contact: Closed (<1 ohm) when de-energized - **Pass If:** Contact state matches specification ### TEST 2: State Change Test - **Do:** Activate equipment (turn pump/fan ON) - **Expect:** * NO contact: Changes from open to closed * NC contact: Changes from closed to open * Controller binary input changes state - **Pass If:** State changes when equipment operates ### TEST 3: Manual Contact Test (if accessible) - **Do:** Manually operate contact (close/open by hand if possible) - **Expect:** Controller input responds immediately - **Pass If:** Controller sees state change ### TEST 4: Graphics/Controller Display - **Do:** Observe controller graphics or display - **Expect:** Binary input status updates in real-time - **Pass If:** Display matches actual equipment state ### TEST 5: Alarm Function Test - **Do:** Trigger alarm condition (if monitoring alarm) - **Expect:** Controller alarm activates - **Pass If:** Alarm notification works correctly ### TEST 6: Load Switching Test (if contacts switch power) - **Do:** Verify contact rating adequate for load - **Measure:** Current through contact (if switching power) - **Pass If:** Contact operates without chattering or overheating --- ## TROUBLESHOOTING ### BINARY INPUT ALWAYS FALSE (Never TRUE) 1. **Check equipment:** Is device actually running? 2. **Test contact:** Measure continuity across contact - **If open when should be closed:** Contact not closing - device issue 3. **Check wiring:** Verify connections at both ends 4. **Test continuity end-to-end:** Should be <5 ohms when closed 5. **Verify controller config:** Input set to correct contact type (NO vs NC)? 6. **If wiring OK but no response:** Controller input may be failed ### BINARY INPUT ALWAYS TRUE (Never FALSE) 1. **Check equipment:** Is device actually off? 2. **Test contact:** Should be open when equipment off - **If closed when should be open:** Contact stuck - device issue 3. **Check for short circuit:** Wires touching somewhere 4. **Verify controller config:** May be configured backwards (NO vs NC) 5. **If persistently closed:** Contact welded shut or wiring short ### BINARY INPUT ERRATIC / CHATTERING 1. **Mechanical chatter:** Contact bouncing during switching - Solution: Add time delay in controller (0.5-1 sec) 2. **Loose wiring:** Check all connections tight 3. **EMI/RFI interference:** Route wiring away from power cables 4. **Contact arcing:** Contact switching too much current - add relay 5. **Vibration:** Secure device and wiring to prevent movement ### BINARY INPUT REVERSED (Shows opposite of actual) 1. **Controller config:** Input configured as NO when should be NC (or vice versa) 2. **Solution:** Change controller configuration to opposite type 3. **Verify logic:** Some controllers use "Active High" or "Active Low" ### ALARM NOT TRIGGERING 1. **Verify binary input changing state:** Check controller display 2. **Check alarm configuration:** - Alarm enabled? - Correct trigger condition (state change vs specific state)? - Time delay too long? 3. **Check notification routing:** Email, text, or on-screen only? ### VOLTAGE SENSING NOT WORKING 1. **Check voltage present:** Measure with multimeter at monitored circuit 2. **Verify voltage sensing module powered:** Some require separate power 3. **Check voltage rating:** Module rated for monitored voltage? 4. **Test module output contacts:** Should close when voltage present 5. **If voltage present but module no output:** Module failed - replace --- ## ESCALATION - COMPLETE BEFORE CALLING ### PRE-ESCALATION CHECKLIST - [ ] Verified equipment actually operating (visual/audible) - [ ] Tested contact continuity (open vs closed) - [ ] Verified all wiring connections tight - [ ] Tested continuity end-to-end (<5 ohms when closed) - [ ] Checked controller configuration (NO vs NC) - [ ] Verified binary input point configured in controller - [ ] Documented actual equipment state vs controller reading - [ ] Taken photos of wiring ### PROVIDE THIS INFO - **Monitored Device:** [Type / Location] - **Contact Type:** NO / NC / Voltage sensing - **Equipment State:** ON / OFF / Cycling - **Contact Continuity:** Open / Closed / _____ ohms - **Controller Reading:** TRUE/1 / FALSE/0 / Erratic - **Controller Config:** NO / NC / Unknown - **Symptoms:** [Always false, always true, erratic, reversed] - **Steps Taken:** [Troubleshooting completed] ### CONTACTS - **Field Specialist:** [Phone] - **Programmer:** [Phone] (if alarm/logic issue) - **Electrician:** [Phone] (if device repair needed) - **Dispatch:** [Phone] --- ## COMMON APPLICATIONS & WIRING ### PROOF OF OPERATION (Most Common) **Pump/Fan Status:** - Source: Auxiliary contacts from motor starter (NO) - Wiring: NO contact → Controller BI - Logic: Closed when running = TRUE = Equipment ON - Alarm: If FALSE for >60 seconds = Failed to start **VFD Run Status:** - Source: VFD auxiliary relay output (NO) - Wiring: Relay NO contact → Controller BI - Logic: Closed when VFD running = TRUE - Alarm: Command ON but status FALSE = VFD fault **Valve/Damper End Switch:** - Source: Mechanical limit switch at actuator (NO or NC) - Wiring: Switch contact → Controller BI - Logic: Closed when fully open (or closed) = TRUE - Alarm: Position doesn't match command = Stuck actuator ### ALARM MONITORING **Fire Alarm Interface:** - Source: Fire alarm panel relay (NC typical) - Wiring: NC contact → Controller BI - Normal: Closed = TRUE = No alarm - Alarm: Opens = FALSE = Fire alarm active - **Critical:** Fail-safe design (wire break = alarm condition) **Freeze Stat (Low Temp Alarm):** - Source: Capillary tube thermostat (NC) - Wiring: NC contact → Controller BI - Normal: Closed = TRUE = Temp OK - Alarm: Opens = FALSE = Freeze condition - Action: Shut down system, notify operator **High Static Pressure Switch:** - Source: Pressure switch (NC typical) - Wiring: NC contact → Controller BI - Normal: Closed = TRUE = Pressure normal - Alarm: Opens = FALSE = High pressure - Action: Shut down fan, check filter **Flow Switch (Proof of Flow):** - Source: Paddle-type flow switch (NO) - Wiring: NO contact → Controller BI - Normal (flow): Closed = TRUE = Flow proven - Alarm: Open = FALSE = No flow detected - Action: Check pump operation, strainer, valves **Smoke Detector:** - Source: Duct smoke detector relay (NC) - Wiring: NC contact → Controller BI - Normal: Closed = TRUE = No smoke - Alarm: Opens = FALSE = Smoke detected - Action: Shut down air handler, activate smoke control ### STATUS MONITORING **Filter Differential Pressure Switch:** - Source: Differential pressure switch (NO) - Wiring: NO contact → Controller BI - Normal: Open = FALSE = Filter clean - Alarm: Closed = TRUE = Filter dirty (high ΔP) - Action: Schedule filter change **Water Leak Detector:** - Source: Water detection sensor (NO) - Wiring: NO contact → Controller BI - Normal: Open = FALSE = No water - Alarm: Closed = TRUE = Water detected - Action: Shut down equipment, investigate leak **Door/Window Contact:** - Source: Magnetic reed switch (NC) - Wiring: NC contact → Controller BI - Normal: Closed = TRUE = Secure - Alarm: Open = FALSE = Door/window open - Action: Adjust HVAC for infiltration --- ## WIRING DIAGRAMS ### Dry Contact - NO (Normally Open) ``` Equipment Controller Aux Contact Binary Input ┌─┐ ┌────┐ │ │ │ BI │ NO │ │──────────────│ 1 │ │ │ │ │ │ │──────────────│COM │ └─┘ └────┘ ``` ### Dry Contact - NC (Normally Closed) ``` Equipment Controller Aux Contact Binary Input ┌─┐ ┌────┐ │█│ (closed) │ BI │ NC │█│──────────────│ 1 │ │█│ │ │ │█│──────────────│COM │ └─┘ └────┘ ``` ### Voltage Sensing (Line Voltage) ``` Line Voltage Voltage Sensor Controller 120VAC RIBS Module Binary Input ┌──┐ ┌──┐ ┌────┐ HOT │ │───────────│IN│ │ │ │ │ │ │ NO ┌───│ BI │ NEU │ │───────────│ │───────┤ │ 1 │ └──┘ │ │ └───│COM │ └──┘ └────┘ ``` --- ## COMMON ISSUES & TIPS ✓ **NO vs NC confusion:** Most common wiring error - verify contact type before wiring ✓ **Fail-safe design:** Use NC contacts for critical alarms (wire break = alarm) ✓ **Fire alarm interface:** Always NC contact - must fail to alarm condition ✓ **Controller configuration:** MUST match actual contact type (NO vs NC) ✓ **Contact ratings:** Don't exceed contact amp/voltage rating ✓ **Time delays:** Add 0.5-1 sec delay to prevent contact bounce false alarms ✓ **Wire routing:** Keep binary input wiring away from high-voltage to prevent interference ✓ **Voltage sensing:** Use when no dry contacts available (direct voltage monitoring) ✓ **Status feedback:** Always verify equipment actually operating (BI shows contact state, not mechanical operation) ✓ **Alarm logic:** "Alarm on change" vs "Alarm on state" - choose correct ✓ **Multiple contacts:** Can wire multiple NO contacts in series for "ALL ON" logic ✓ **Multiple contacts:** Can wire multiple NC contacts in parallel for "ANY ALARM" logic --- **Document ID:** SSO-BINARY-INPUT-001 **Revision:** 1.0 **Next Review:** Dec 2026