The AB 1771-DBMEM1 is a Memory Module for PLC 5 1771-DB Basic Module. It has an 8-KB EEPROM for attaching to a 1771-DB Basic module to increase user memory. The 1771-DB module provides an easy interface between a PLC-5 processor, 1771 backplane, and an RS-232, RS-422, or an RS-485 device. The 1771-DBMEM1 can also communicate with a remote SLC processor or remote device across the DH-485 network via a DH-485 port. It provides fast communication independent of the processors. It allows for data analysis and manipulation gathered from the processors and unattended report generation. The 1771-DBMEM1 saves processor memory by solving complex math or application-specific problems. It has application in various remote communication devices such as computers, printers, modems, and other third-party devices.


The 1771-DBMEM1 module has isolation voltage of 500V DC from port-to-port and port-to-backplane. It has a 32-KB battery-backed RAM and a 24-KB available user memory. It has communication rate ranging from 300 – 19.2 Kbps. It has a backplane current load of 0.75A with a DH-485 interface connected to the DH-485 port and a load of 0.65A without a device connected to the DH-485 port. The 1771-DBMEM1 has a time-of-day clock with a 10ms resolution and maximum power dissipation of 4W. For installation, it takes one slot in the I/O chassis and supports the BASIC and C programming languages. It requires 2 ports for RS-232, RS-422, or RS-485 and 1 port for DH-485 connections.


The 1771-DBMEM1 module supports BASIC statements and commands and its additional 128 calls. It has Block-transfer capability which allows complete data transfer between the data table and the module’s memory, thus minimizing user programming. The 1771-DBMEM1 has 8 defined and 2 user-defined indicators for troubleshooting and indicators.