HA71 Digital Gas Controller 

The Honeywell Analytics HA71 16 Channel Digital Gas Controller  provides simultaneous display and alarm functions for up to 16 input variables. The HA71 can expand with up to ten additional HA71 units to provide up to 160 points of gas detection.

A graphic LCD displays monitored data as trends, bar graphs and engineering units. Three adjustable alarm levels are provided per channel. Relay outputs allow control of beacons horns and other alarm events. A horn relay may be set for steady or pulsing operation. Nonvolatile memory retains all configuration data indefinitely.

Analog inputs may be accepted and conditioned via sensor specific analog input cards. Alternatively, the standard Modbus Master port allows input data to be retrieved from Modbus slave devices including the many Modbus compatible Honeywell Analytics sensor transmitter products.

The HA71 is easy to configure and user friendly. Measurement ranges in engineering units, adjustable alarm set-points, dual serial interfaces and many other features combine to allow the HA71 satisfy the needs of many demanding applications. It is widely used for centralizing the display and alarm processing functions in critical multipoint monitoring applications. The optional HA-71-HMI (Human Machine Interface) software provides complete data display and storage, with real-time channel data available in 24-hour or 15-minute trends, including historical alarm and maintenance data.

A RS-485 Modbus slave port allows up to 128 HA71’s to be multidropped onto a single data highway for interrogation by another Modbus master. HA71’s may also be cascaded by connecting one unit’s master port to another’s slave port and others are added by connecting appropriate 8 channel boards (2 required for more than 8 channels) to the economical I2C expansion bus. Familiar “telephone style” cables and connectors interface to this bus. This method allows versatile system configuration of options satisfying the most unusual user applications.

HA71 facilitates monitoring of ambient gas detection, rotating machinery, tank levels, flow, temperature and other controls.  

Features & Benefits Accessories Technical Library Image Gallery

Trouble-free operation--menu driven easy calibration, no moving parts
• Improved drift and temperature compensation

• Accepts inputs from up to 16 4-20mA sensors transmitters.

• CSA certified to C22.2 NO. 152 for combustible detection and Class I, Div. 2, Groups A,B,C,D CE


• Touch & magnetic keypad for nonintrusive operation in potentially hazardous locations

• NEMA 4X (Div. 2 certified) and Explosion-Proof wall mount packaging options available

• 3 independent alarm levels per channel. Relay Acknowledge feature allows silencing of external audible devices during existing alarm conditions

• Graphic LCD readout displays monitored data as bar graphs, trends and engineering units
• Cal Mode offers pushbutton zero / span calibration for direct sensor interface applications. Authorization Mode allows locking of critical configuration variables








  • Discrete alarm relays ( per channel)
  • 4-20mA I/O direct sensor input
  • HMI data display/storage software
  • Public Documents
    Date Title Type File Size
    28 Feb 11 Gas Detection for the Water Treatment Industry 459 kb
    28 Feb 11 Controllers brochure 440 kb
    28 Feb 11 Controllers spec sheet Datasheet 293 kb
    01 Apr 13 Fixed-Point Industrial Fire and Gas Detection Brochure 1,194 kb

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    02 May 12 HA-71 Digital Gas Controller Technical Manual Manual / Supplement 3,545 kb
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     Gas Detection Explained

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