Honeywell 2MLF-AC4H MasterLogic ML200 Analog Input Module

The Honeywell 2MLF-AC4H is a 4-channel analog input module engineered for the MasterLogic ML200 PLC series. It processes current field signals with a high 1/64000 digital output resolution and enables bidirectional HART communication overlaid on standard 4-20 mA analog wiring without requiring separate digital networks.

Analog Signal Acquisition and HART Integration

The module accepts current input ranges of 4-20 mA (with HART protocol support) and 0-20 mA (without HART support). It achieves an accuracy of +/-0.1% at 25 deg C with a temperature coefficient of +/-0.25%, providing stable signal processing across ambient temperature fluctuations. Field signals connect via an 18-point terminal block connector.

The integrated HART interface enables remote device configuration, process variable access, and field instrument diagnostics directly through the primary signal pair.

Output Formatting and Diagnostics

Converted analog signals can be scaled into signed values (-32000 to 32000), precise values, or percentile representations (0 to 10000). The module features automatic input disconnection detection on the 4-20 mA range to detect open loop or sensor failure conditions.

Board assembly incorporates protective coating to safeguard components in harsh operating environments. Internal power draw is approximately 340 mA at 5 VDC from the system backplane rail.

Technical Specifications

Frequently Asked Questions

Q: Is HART communication supported on both current input ranges of the 2MLF-AC4H module?

A: No, HART communication is supported exclusively on the 4-20 mA current loop range. It is not supported on the 0-20 mA range.

Q: How does the module indicate open field circuit or sensor failures?

A: It features built-in input disconnection detection that identifies loop breaks when operating within the 4-20 mA signal range.

Q: What output data formats can be selected for signal processing?

A: Converted values can be formatted as Signed Values (-32000 to 32000), Precise Values, or Percentile Values (0 to 10000).