Honeywell HA71 Digital Gas Controller

• Accepts up to 16 inputs from many sensor types and signal ranges. Inputs may be analog, or Modbus Master capability allows input data to be retrieved via RS-485 data highway reducing wiring costs at installation
• 8 channel display mode and option boards allow economical configuration of systems requiring only 8 channels or less
• Dual Modbus RS-485 ser ial ports for simultaneous master / slave operation. Optional phone modem 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 trends, bar graphs and engineering units. Alarm LED’s flash when new and become steady after acknowledged
• Standard A SPDT common alarm relays for HORN, HIGH, WARN & FAULT. Optional discrete channel alarm relays also available
• Options such as alarm event printer interface, direct sensor inputs, 4-20mA outputs, discrete alarm relays and others are sup-ported via an I 2C expansion bus
• Cal Mode offers pushbutton zero / span calibration for direct sensor interface applications. Authorization Mode allows locking of critical configuration variables
• Magnetic keypad available for non-intrusive operation in potentially hazardous locations
• NEMA 4X, Explosion-Proof, surface mount, panel and rack mount packaging options available
   

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. These include monitoring of ambient gas detection, rotating machinery, tank levels, flow, temperature and others.

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.