1756-IF8H | Allen-Bradley 8 Point Hart Analog Input Module

The Allen-Bradley 1756-TBCH is an analog input module from the ControlLogix controller platform This module mainly features Eight (8) differential input channels, compatible with Voltage and current signals. It also has an added compatibility with Highway Addressable Remote Transducer (HART) protocol having a single HART modem per module. Configurable current signals to the 1756-IF8H include industry-standard 0-20 mA and 4-20 mA. For voltage input signal, supported voltages are +/-10VDC, 0-5 VDC, 1-5 VDC, and 0-10 VDC. This module has a resolution range of 16-21 bits with a backplane current requirement of 300 mA @ 5.1 VDC and 135 mA @ 24 VDC. It has a total backplane power consumption of 4.77 Watts while the thermal dissipation varies depending on the configured signal. For voltage signal processing, the thermal dissipation is 11/0 BTU / hr while for current, 13.7 BTU / hr. It comes with an open-circuit detection time of 5 seconds and overvoltage protection of 30 VDC and 8 VDC for voltage and current signal configuration, respectively. This module is a single-width module, therefore, occupies a single slot of a 1756 chassis. It can be part of a local I/O or distributed I/O system. The 1756-IF8H has a HART scan time of 18...488 ms and 1 second if HART enabled while with all channels HART activated, the estimated scan time is 10 seconds. Module passthrough configuration and communication to HART communication and devices may significantly increase scan time. The 1756-IF8H uses successive approximation as input conversion method while output conversion method is via R-Ladder DAC, monotonicity with no missing codes.

The Allen-Bradley 1756-IF8H is a HART Analog Module belongs to the ControlLogix system. It requires a 36-position spring clamp RTB, or removable terminal block housing, and it can either be the 1756-TBCH or 1756-TBS6H and is compatible with the HART 5, 6, and 7. 8 differential voltage or current inputs are available for this module, with one HART modem per module. This 1756-IF8H input module receives signals from process value transmitters and then converts them to the corresponding measurement values for use in the Logix controller. The 1756-IF8H has three data formats for you to choose from using the Studio 5000 Logix Designer: analog only, analog and HART PV, and analog and HART by channel. If you want the members of the tag to be arranged like those of non-HART analog input modules, you should choose the analog and HART PV format. Analog values are grouped together near the end of the tag, making it easier to view all 8 analog values at the same time. But if you want the Status, Analog Value, and Device Status for every channel to be grouped together in a tag, you should choose the analog and HART by channel format. This will make it easier for you to view all data related to a field device.

Using this module will let you have an analog and HART connectivity in one module HART commands can be transmitted as unscheduled messages with the 1756-IF8H. Other features of the 1756-IF8H include multiple current and voltage input ranges, real-time sampling, process alarms, wire-off detection, module filter, under-range and over-range detection, rate alarm, and highway addressable remote transducer (HART) communication. The 1756-IF8H has variable operational ranges for every channel in the module. Possible ranges for you to choose from include -10 to 10 Volts, 0 to 5 Volts, 0 to 10 Volts, 0 to 20 milliamps, and 4 to 20 milliamps, with HART instruments using the latter range. The resolution of this module ranges from 16 to 21 bits. Backplane voltage and current ratings are 5.1 Volts DC, 300 milliamps, 24 Volts DC, and 135 milliamps and its total backplane power is 4.77 Watts. Voltage power dissipation is 3.21 Watts and 4.01 Watts for the current and it also has a maximum overvoltage protection of 30 Volts DC (voltage) and 8 Volts DC (current).