The 1794-IE8H is an HART capable analog input module. This module is manufactured by Allen-Bradley and supports the Highway Addressable Remote Transducer (HART) communication protocol. This module is also a high resolution module, and capable of bipolar and unipolar configuration.

The 1794-IE8H features Eight (8) non-isolated, single-ended analog inputs, supporting analog signal ranges of 0-20 mA and 4-20 mA. The module’s resolution is 16-bit resolution with an accuracy of 0.1% Full Scale @ 20 °C (68°F) and accuracy drift with temperature of 0.05% Full Scale for 0 °C...55 °C (32...131 °F).

With HART protocol support, the module’s data and operational state may be accessed. HART is an open protocol that can be used to communicate 4-20 mA analog instrumentation loops.

The 1794-IE8H is compatible with communication adapters such as ControlNet adapters, Ethernet adapters, and ProfiBus adapter with catalog number 1794-APBDV1 only. ControlNet revision 5.1 or greater and Ethernet Revision 4.2 or greater are compatible for a Series B HART Module with a series B profile.

This HART capable module comes with a local microprocessor for handling advanced features, support for multiple data format and ranges that are individually configurable and capable of detecting module alarms such as lead breakage detection, overrange/underrange alarms and remote transmitter alarm.

Aside from the integrated alarm sensing capability, the 1794-IE8H is also built with Eight (8) fault indicators, Eight (8) channel indicators and One (1) power indicators. The module has an isolation voltage rating of 50V (continuous), Basic Insulation Type Routine tested at 850V DC for 1 s, between field side and system.

It has 8 single-ended, non-isolated HART interface inputs. This module comes with status indicators where in 8 of these indicators are red fault indicators, 8 are yellow channel indicators, and 1 is a green power indicator. The 1794-IE8H inputs have selectable filters. This module also has a resolution of 16 bit unipolar and 15 bit bipolar. Terminal base units compatible with the 1794-IE8H module are the 1794-TB3G and the 1794-TB3GS. No enclosure is needed.

The 1794-IE8H module features a remote transmitter alarm, lead breakage detection, local microprocessor intelligence for the advanced features, over-range and under-range alarms, data ranges that the user can independently program in channel groups, and it can function without switches or jumpers. Its configurable features are the input filter cutoff, fault mode, data format, high/low error level, and the remote transmitter error correcting feature. To configure these features, use the PLC programming software’s I/O configuration. The default input range for the 1794-IE8H is 0 to 20 mA. It has a voltage rating of 19.2 to 31.2 Volts DC and comes with a functional data range of more than 23 Volts at 0 mA and more than 17 Volts at 22 mA. It also has a nominal external DC supply current of 295 mA at 24 Volts DC. Its functional data range is greater than 17 Volts at 22 mA and greater than 23 Volts at 0 mA. The module’s flexbus current external input is 5 Volts DC 80 mA and 24 Volts DC 190 mA.

The 1794-IE8H module has an absolute accuracy of 0.1% full scale at 20 degrees Celsius, while its accuracy drift with temperature is 0.05% full scale for 0 to 55 degrees Celsius. This module has no isolation between channels however, it is rated for 50 Volts continuous isolation voltage between the field side and system. The maximum power dissipation is 3.9 W and maximum thermal dissipation is 13.5 BTU/hour, both at 31.2 Volts DC. The 1794-IE8H’ step response to 99% is 80 milliseconds and it has a voltage variation of 10 milliseconds interruption on DC supply ports. It has an operating temperature of -20 to 55 degrees Celsius and a non-operating temperature of -40 to 85 degrees Celsius. Its operating vibration is 2 g at 10 to 500 Hertz and it also has an operating and non-operating shock of 15 g.