1785-L20E Product datasheet  

1785-L20E Functional Description

The Allen-Bradley 1785-L20E Controller Module is a versatile PLC5 processor that serves as a key part of the legacy PLC5 product family. It is a single-slot module designed to be compatible with 1771-A1B, -A2B, -A3B, -A3B1, and -A4B chassis, making it ideal for medium-range automation needs. The Allen-Bradley 1785-L20E Controller Module can handle up to 512 I/O (mixed) or 512 complementary I/O, which allows for efficient control of connected field devices.

This controller boasts a built-in 16K words of volatile memory, powered by the 1785-XYC Lithium battery. This battery ensures the SRAM content remains intact even when power is lost. For added reliability, optional non-volatile memory backup devices like the 1785-ME16 (16Kwords), 1785-ME32 (32Kwords), 1785-ME64 (64Kwords), and 1785-ME100 (100Kwords) can be installed to enhance system uptime.

Communication is key for this controller, which includes multiple interfaces: one DH+ port, a DH+/Remote I/O combination port, a serial port (RS-232, 423, RS-422A), and an Ethernet port supporting 10/100 Mbps transmission. The Allen-Bradley 1785-L20E Controller Module supports up to 13 chassis, with one local and up to twelve remote I/O racks, making it highly scalable.

With 512 I/O link capacity, the Allen-Bradley 1785-L20E Controller Module supports various data types such as Integer, Float, Block, and String. It operates with an Allen Bradley 1770-XYC Lithium battery and features a calendar/clock with high accuracy. Its maximum I/O scan time is 10 milliseconds at 57.6 kbps and 3 milliseconds at 230.4 kbps, ensuring fast processing speeds.

Operating within a temperature range of 32 to 140°F, the Allen-Bradley 1785-L20E Controller Module can withstand a shock of 30G and vibration up to 1G. It is built to meet industrial standards, with CSA, UL, and C-certifications, ensuring robust performance in demanding environments.