Allen Bradley1772LXMini-PLC-2/16 Processor Module, 4K Word Memory, 256 I/O, Series D

Product Description

What this part is

Allen-Bradley 1772-LX Mini-PLC-2/16 processor module, Series D Revision E. Controller Platform: PLC-2. Product Type: Programmable controller processor. Memory Capacity: 4,000 words. Data Table Expansion: 3,968 words. Maximum I/O: 256 points. I/O Addressing: half-slot, single-slot and two-slot. Mounting Type: 1771 chassis slot. Unit Quantity: 1 Pc.

Decoding the designation

1772 — the Mini-PLC-2 processor family, which runs the same 1771 I/O rack hardware as the larger PLC-2 processors.

LX — the Mini-PLC-2/16 processor, the 256-point member of the family, supplied for a separate 1771-family power supply.

Series D — the fourth hardware revision of the module.

Rev E — the firmware revision level carried on this unit.

What these specs mean in practice

Memory Capacity: 4,000 words. That is the total program and data space the processor addresses, and it is the number that decides whether an existing PLC-2 program will load without editing.

Maximum I/O: 256 points. The processor scans up to 256 discrete points across its 1771 racks, which sizes the machine it can run.

I/O Addressing: half-slot, single-slot and two-slot. Half-slot addressing doubles the point density a chassis can carry; two-slot addressing matches the original PLC-2 convention and keeps legacy rack layouts and their addresses intact.

Instruction Set: arithmetic add, subtract, multiply and divide, square root, BCD to binary and binary to BCD conversion, FIFO load and unload, log10, sine, cosine and power-of-ten. The maths instructions let scaling and totalising run in ladder without an outboard computing module.

Front panel and diagnostics

Mode Selection: keyed front-panel switch. Indicators: front-panel diagnostic LEDs reporting processor and memory status. The key switch fixes run and program mode at the module, so a mode change is a physical act on the panel rather than a software one.

Quantity and configuration

Unit Quantity: 1 Pc. One processor module. Power is taken from a separate 1771-family power supply; the 1772-LXP is the equivalent processor with the supply integrated.

Interchange guidance

Manufacturer Status: discontinued. Part Number: 1772-LX. MPN Variants: 1772LX, 1772 LX, PLC-2/16. Within the Mini-PLC-2/16 range the 1772-LXP carries an integral power supply and the 1772-LXD is the extended-memory execution, so those two are related processors rather than drop-in equals for this catalogue number. Series D Rev E hardware runs the same 1771 I/O modules as earlier series of the 1772-LX.