Allen Bradley 1797-IE8 Flex Ex Analog Input Module

Configured for high-density signal acquisition in hazardous environments, the Allen Bradley 1797-IE8 (1797-IE8 FLEX Ex Analog Input Module) provides direct physical and electrical execution of 8-channel non-isolated analog input processing within hazardous area zones.

Hardware Specifications

Intrinsic Safety and Field Network Stability

The 1797-IE8 integrates intrinsic safety (Ex i) barriers, achieving compliance for Ex ia IIB/IIC T4 or Class I, II, III Division 1 environments. The module maintains DIN-rail mounting stability via standardized 1797-TB3 or 1797-TB3S terminal bases, ensuring consistent electrical contact across the backplane. To mitigate protocol conversion latencies, the module utilizes a 4 ms step response time, allowing for deterministic signal sampling in control loops. Surge voltage protection limits are implemented within the input stage to prevent damage from transient energy sources. System status and diagnostic health are monitored through an 8-channel fault LED array and a dedicated module power indicator.

Frequently Asked Questions

Q: Is this module hot-swappable in a hazardous environment?

A: Yes, the 1797-IE8 supports insertion and removal under power (RIUP) provided the installation is within an approved FLEX Ex system configuration and the local hazardous area safety permit allows for such maintenance.

Q: What is the required key switch position for this module?

A: The module must be configured with a key switch position of 3 to ensure mechanical compatibility with the corresponding terminal base and to prevent improper module insertion.

Field Installation Guidelines

1. Mounting: Snap the 1797-TB3 or 1797-TB3S terminal base onto the DIN rail. Verify the key switch is set to position 3 before installing the module.
2. Wiring: Use stranded conductors up to 4 mm2 (12 gauge) for input connections. Route intrinsically safe signal wiring separately from non-intrinsically safe cabling to prevent hazardous coupling.
3. Shielding: Terminate cable shields at the ground lug on the terminal base to ensure a low-impedance path to earth and to minimize noise interference.
4. Configuration: Set the data format via the host software to match the required resolution (16 bits) and range of the connected field instrumentation.
5. Verification: Inspect the 8 red fault indicators to confirm input integrity and monitor the green module power indicator to verify sufficient field-side power (7.5 W).