TECHNICAL SPECIFICATIONS

The Allen-Bradley 1756-IF8 ControlLogix analog input module is commonly used to connect instruments and equipment that generate analog signals, such as transmitters, transducers, signal splitters, signal isolators, panel meters, and other devices with comparable capabilities. It has eight input channels that may be configured for a range of input signals, including 0...20 mA for current signals and 0...10V dc, 0...5V dc, and ±10V dc for voltage signals.

The single-slot 1756-IF8 analog input module has a high conversion resolution. It has several resolutions. The number of significant bits is 16, which corresponds to 65,536 counts. The resolution is 320 µV per count at an input range of ±10.25 V, 160 µV per count at an input range of 0...10.25 V, 80 µV per count at an input range of 0...5.125 V, and 0.32 µA per count at an input range of 0...20.5 mA.

There is essentially no restriction on how many times this module may be installed. Up to 4000 analog I/O signals can be supported by most ControlLogix controllers. The 1756-IF8 analog input module may be installed adjacent to the controller in the local chassis or distributed I/O racks.

Sigma-Delta signal conversion and IEEE 32-bit floating point data storage format are also capabilities of the 1756-IF8 analog input module. It makes use of user-defined, mechanical keying on the 1756-TBCH and 1756-TBSH removable terminal blocks (RTB).

Depending on the needs of the user and the application, the 1756-IF8 analog input module may be connected in single-ended, differential, or high-speed differential wiring. The single-ended method works well when every input device is connected to the same ground. To give digital data to a controller, the module first determines the difference between the signal ground and one side of the input of the signal.

Differential wiring is advised for uses where there may be separate signal pairs or where there is no shared common ground. This wiring technique is also suitable for environments that call for improved noise immunity. In a differential mode, the channels are not isolated from one another. The reading of one channel may have an impact on the reading of some other channel if multiple differential input signals make use of various common voltage references. Users should connect the input on distinct modules or replace the non-isolated module with an isolated module if this occurs.

The high-speed differential wiring approach enables the fastest data changes. The wire configuration affects how long it takes the module to scan. For single-ended, differential, and high-speed differential wiring, the scan time is 16 to 488 ms, 8 to 244 ms, and 5 to 122 ms, respectively.

Module filter, under-range/over-range detection, process alarms, wire-off detection, various input ranges, real-time sampling, digital filter, and rate alarms are characteristics specific to the 1756-IF8 analog input module. The highest current ratings for its backplane are 150 mA at 5.1V dc and 40 mA at 24V dc. The device has a 1.73 Watt power consumption and maximum overvoltage protection of 30V dc.