• Sensorsoft Real Time Voltage & Contact Sensor (RS232)

The Sensorsoft Real-Time Contact and Voltage Sensor (SS6420) has 15 Boolean inputs that allow you to connect and monitor, in real-time, the state of dry contact based sensors and voltage sources. It also includes two relay outputs (SPDT) for controlling low voltage actuator loads such as lamps, audible alarms or solenoids. The SS6420 is housed in a mountable plastic module with screw terminal strips where external dry-contact security devices, voltage sources and actuator loads can be connected. The SS6420 communicates with the monitoring host/software over an RS232 serial port or 10/100 Base-T Ethernet interface.

Applications for the SS6420 include, but are not limited to monitoring/controlling the following:
•motion, glass-break and door sensors for physical security and activity
•smoke and fire detectors/systems
•diesel generators activity
•gas leak detectors
•AC power supplies or battery voltages
•door strike or lock solenoid
•door chimes and buzzers
•photocell detection of room lighting
•dry contact monitoring

The SS6420 is based on the Sensorsoft Device Protocol (Version 3.0) and includes protocol enhancements that immediately detect and report a state change on any of its dry-contact monitor inputs. For this reason you will know immediately when a door closes or a motion sensor triggers without waiting for a polling interval. The SS6420 works with Sensorsoft Remote Watchman Enterprise software. You can also develop your own software for the SS6420 using our Simple Text Command interface or our free Windows developer tools.

Similar to alarm panels, the SS6420 has a peripheral DC power supply for dry contact based detectors or actuator loads that require such to operate (i.e. motion sensors, smoke detectors, solenoids). This supply voltage is made available through screw terminals.

Two models of the SS6420 are available. The lower cost RS232 model (SS6420J) is powered by the serial interface from the RTS and DTR lines. It can be located up to 80 feet (24 m) from the serial port (depends on serial port) without the need for extenders or amplifiers. The Ethernet model (SS6420E) with its 10/100 Base-T interface has the advantage of direct IP connectivity without the need for a separate IP based device server. The SS6420E is supplied with a AC-DC mains power adapter or PoE adapter.

User Guide

General Features
•Monitor up to 12 dry contacts simultaneously
•Monitor up to 3 voltage sources with optical isolation
•Supports Sensorsoft Device Protocol (SSDP) or Simple Text Commands
•Provides 2 SPDT relays controllable by software
•Detects real-time pulses as short as 60 mS
•Responds to real-time state changes within 300 mS
•Option to filter out unwanted short pulses
•Terminals to distribute power to external peripheral devices
•Operates in polled or real-time mode
•Custom Boolean state strings and descriptions can be assigned to each input
•Serial RS232 model (SS6420J) does not require a power supply to operate *
•Ethernet model provides direct IP connectivity (no device server required)
•All power supplies protected by self-healing fuses
•Works with our full line of dry-contact security and safety detectors




Total Number of Monitored Inputs: 15
 (12 - contact inputs, ground referenced, numbered C1-C12)
 (3 - opto-isolated voltage inputs, not ground referenced, numbered V1-V3)
Total Number of Controlled Outputs: 2
 (2 - SPDT electromagnetic relay contacts (NO, NC, COM), numbered RL1 and RL2)
Screw Terminal Connectors: 8 connectors x 6 polls/connector (48 poles total), 3.50 mm pluggable screw-down connector, AWG 16-24, Molex P/N 39351-0006.
Relay contact load rating (RL1 or RL2): 1.5 Amp at 30 VDC
Maximum relay contact operating voltage (RL1-RL2): 30 VDC
Maximum relay contact operating current (RL1-RL2): 1.5 Amp
Maximum relay contact switching capacity (RL1-RL2): 62.5 VA, 33 W
Detection Method - Contact Inputs (C1-C12): Input transistor circuit detects external resistance between input and ground terminals. External resistances below 15K ohm produce a CLOSED condition/state. External resistances above 600K ohm produce an OPEN condition/state.
Input Resistance of Opto-isolated Voltage Inputs (V1-V3): 16K Ohm
Detection Method - Opto-isolated Voltage Inputs (V1-V3): Optical coupler detects voltage difference between V+ and V-. A voltage difference, on these terminals, below approximately 3 volts produces an OFF condition/state. A voltage difference, on these terminals, equal to or greater than approximately 3 volts produces an ON condition/state. The minimum recommended voltage input for an ON condition/state is dependent upon resistance of the voltage source.
Minimum Detectable Input Duration: 60 mS. This specification is not valid during a write to any variable in the SS6420’s non-volatile memory.
Maximum Time from State Change to Issue of Interrupt Packet: 300 mS. This specification is not valid during a write to any variable in the SS6420’s non-volatile memory.
Maximum Applied Voltage on Opto-isolated Voltage Inputs (V1-V3): 30 V
Power source: Port-powered (RTS and DTR, both asserted) or using an external AC-DC power adapter. To operate relay contacts, requires external power.
Power supply current drain: < 20 mA
External Power Source Connector: 2.1 mm jack
External Power Source Requirements: 6 VDC, 20 mA capability, center positive (input circuit is polarity protected). Recommended power adapter is P/N PA6106.
Peripheral DC Power Source: for external peripheral devices
Peripheral Power Source Connector: 2.5 mm jack
Peripheral Power Source Requirements: Center negative (input circuit is polarity protected). The input DC voltage will depend on the requirements of peripheral devices that the customer is powering. The maximum input voltage allowed is 30 VDC. The maximum current that can be conducted is 0.75 Amp after which the internal overload protection will trigger. The overload protection is provided by a self-healing poly-fuse. This power source is made available through 12 polls of the screw terminal connectors. The recommended power adapter for powering security detectors is P/N PA6420-XX (12 VDC, 1.2 A).

Software Interface

Communications Interface: RS232C using TX,RX,RTS,DTR and GND. One device per serial port.
Communications Settings: 57600 bps, 8 bits, no parity and 1 stop bit
Communications Connector: 8 position modular jack, (accepts 8 position plug, RJ45)
Maximum communications cable length: 24 m (80 ft.) using recommended cable type. Low capacitance shielded cable or UTP is recommended
Firmware Version: 5.08
Communications Protocols: Sensorsoft Device Protocol (SSDP) Version 3.0 or Simple Text Command Interface (see User Manual for commands)
Communications Error Control: (SSDP only) 16 bit CRC (cyclic redundancy checking) for detection of communication errors between the device and host.
EEPROM: 2 Kbytes. Stores user defined input description and Boolean state strings
Number of Variables: 87
Maximum Length of Input Description String: 32 characters
Maximum Length of Boolean State String: 8 characters


Housing Dimensions: 7.5” (190.0 mm) x 2.8” (71 mm) x 1.1" (28 mm)
Housing Material: injection molded ABS thermoplastic
Housing Color: Grey
Operating Temperature Range: -40 º C to +60 º C (-40 º F to +140 º F)
Operating Humidity Range: 90% or less, non-condensing

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Sensorsoft Real Time Voltage & Contact Sensor (RS232)

  • Brand: Sensorsoft
  • Product Code: SS6420J
  • Availability: In Stock
  • £225.00

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