Allen-Bradley 1747-DTAM/B Data Table Access Module

The Allen-Bradley 1747-DTAM/B, also cataloged as the 1747-DTAM/B data table access module, operates as a dedicated hardware interface for processor data table monitoring, modification, and mode control within Rockwell Automation SLC 500 controller systems. The module executes direct read/write access to PLC memory areas and provides local operator interaction through a front-panel LCD interface without requiring programming software.

Suffix Breakdown & Model Matrix

No structured suffix hierarchy is defined for 1747-DTAM/B. The “/B” revision indicates a hardware design iteration within the DTAM product family without functional expansion of core data table access behavior.

Hardware Specifications

Backplane Bus Interaction and SLC 500 Data Table Access Behavior

Within Rockwell Automation SLC 500 architectures, the 1747-DTAM/B interfaces with processor memory via the backplane communication layer, operating as a supervisory terminal rather than a control-executing module. Data table access is performed through structured read/write transactions mapped to controller memory regions, including status words, fault registers, and mode control flags.

The module does not participate in cyclic I/O scanning or deterministic control execution. Instead, it issues asynchronous memory access commands governed by SLC 500 processor arbitration rules. Mode transitions (RUN, PROG, TEST) are executed through controlled state write sequences, with internal validation to prevent invalid mode switching during active scan conditions.

Backplane loading remains minimal due to non-continuous polling behavior, while LCD-driven user interaction introduces human-in-the-loop latency rather than network determinism constraints. The module is functionally dependent on SLC 500 processor availability and does not retain autonomous operational state.

Frequently Asked Questions (FAQ)

Q: Does the 1747-DTAM/B execute control logic independently of the PLC CPU?
A: No. It functions as a memory access and operator interface device and does not execute ladder logic or control tasks.

Q: What happens if the backplane connection is interrupted during operation?
A: All data table access operations are suspended, and the module loses communication with the SLC 500 processor until backplane connectivity is restored.

Q: Can the module operate while the PLC is in RUN mode?
A: Yes. Read operations are permitted in RUN mode, while write and mode changes are subject to processor state restrictions.

Field Installation Guidelines

The module is designed for panel mounting and requires a stable cutout installation with controlled environmental sealing. Power input must be maintained within 12 to 30 VDC with correct polarity alignment.

Backplane or processor interface connection shall be verified before energization to avoid invalid memory access states. Cable routing must be separated from high-noise power conductors to prevent interference with LCD control signals.

Environmental conditions must remain within 0 to 55 deg C and controlled humidity range to maintain display readability and prevent internal condensation on LCD layers.