Allen-Bradley 1747-M1 SLC 500 Memory Device

The Allen-Bradley 1747-M1, also cataloged as the 1747-M1 Memory Device, operates as a dedicated hardware component for non-volatile program and data table storage within SLC 500 network platforms.

Hardware Specifications

Backplane Bus Communication and Firmware Compatibility

The 1747-M1 executes data transfer via the SLC 500 backplane interface. The internal EEPROM architecture ensures data retention without requiring battery-backed RAM, facilitating long-term storage of instruction sets and data tables. Deterministic scan times are maintained through direct backplane integration, with program scan rates synchronized at 0.9 milliseconds. Firmware compatibility is dictated by the SLC 500 processor series; users must ensure the processor revision supports EEPROM flash backup configurations to utilize the 64,000-word user memory capacity effectively. The module interfaces with existing I/O chassis configurations, supporting up to 30 module slots per rack architecture.

Frequently Asked Questions

Q: Does the 1747-M1 module support hot-swapping during processor operation?

A: No. The memory device must be installed or removed only when the SLC 500 processor is in Program mode or when backplane power is removed to prevent data corruption or bus communication errors.

Q: How does the module handle memory overflow when user data exceeds 64,000 words?

A: The 1747-M1 is hard-coded for a 64,000-word limit. Attempting to write a program that exceeds this capacity will trigger a processor fault, requiring a reduction in the data table size or the use of a high-density memory module.

Field Installation Guidelines

1. Static Discharge Prevention: Utilize a grounded wrist strap when handling the 1747-M1 to prevent ESD damage to the EEPROM integrated circuits.
2. Insertion Alignment: Align the module connector pins with the processor memory port. Apply firm, even pressure until the locking mechanism engages.
3. Shielding and Grounding: Ensure the SLC 500 chassis is properly earth-grounded to minimize common-mode noise that may impact backplane communication stability.
4. Firmware Verification: After installation, verify the processor status indicators. A flashing fault LED may indicate a memory mismatch or improper seating of the device.