OI-7543-6 Non-Explosion Proof Monitor with 3 Relays and RS-485 Modbus Output


The Otis Instruments OI-7543-6 six channel Gas Monitor with 3 Dry Contact Relays can monitor up to 6 individual GEN II WireFree Gas Detectors and Transmitters. An RS-485 Modbus output allows for data communication to a PLC or other system monitoring device. The OI-7543-6 is available with an optional WirelessHART® module that allows the received sensor readings to be viewable on a WirelessHART® network. Standard DC or optional AC power options make this monitor a great addition to your gas detection network.

OI-7543-6-[Radio Frequency]-[Power Supply]-I





Product Type: Gas Monitor

Power Type: Wired Power Operating Voltage 12V to 35V DC

Current Draw: 275 mA Maximum

Power Supply: 3.13A (75W), 85/264V AC to 24V DC (Optional)

Protection: Power Electromagnetic Interference (EMI) Filter

Display Screen:

  • 128×64 Resolution Graphical LCD Screen

  • Transflective (Sunlight Readable) with LED Backlight


  • 3 Push-Buttons (MENU, ADD, and SUB)

  • 3 Magnetic Non-Intrusive Switches

Output: RS-485 Modbus Optional WirelessHART® Module (disables RS-485 Modbus Output)

TambTemperature Range: -30°C to +70°C (-22°F to +158°F)

WireFree (Digital) Input: Up to 6 WireFree Sensor Inputs


  • 3 Dry-Contact Relays with 4 Amp Replaceable Fuses

  • Wet Contact Fault Terminal 3 Individually-Configurable Alarm Set-Points/Channel

  • Latching and Non-Latching Relay Settings/Channel

Product Compatibility:

  • GEN II WireFree Sensors and Transmitters

WireFree Radio Options: GEN II 900 MHz Radio OR GEN II 2.4 GHz

Radio Networks:

  • 52 Networks (GEN II 900 MHz Radio)

  • 78 Networks (GEN II 2.4 GHz Radio)

  • 255 Addresses per Network

Enclosure Material: Fiberglass Enclosure w/ Clear Window

Product Dimensions: 8 in. L x 8 in. W x 4 in. H (Max. Dimensions w/ Attachments)

Total Weight: 12.8 lbs.

Hardware Warranty: 1-Year, Limited

Optional WirelessHART® Kit: OI-HART-KIT — WirelessHART® Module with 2.4 GHz external antenna


OI-7543-6 Data Sheet

OI-7543 Operation Manual


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Additional information

Radio Configuration

Gen II 900 MHz Radio, Gen II 2.4 GHz Radio



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