The Cutler-Hammer D100ERA20 is part of the manufacturer’s expanders for Programmable Logic Controllers. This expander serves to expand the input and output capabilities of a controller; connected to the controller by a 30-centimeter cable, the D100ERA20 comes with twenty I/O points comprising of 12 inputs and 8 output ports. The D100ERA20 has an input voltage of 115 Volts AC. The 12 input ports are also powered by 115 Volts AC while the eight output relay-type ports are rated between 24 Volts DC and 230 Volts AC. An expander may be connected to another expander in order to increase I/O ports, but the maximum I/O capacity of the controller must not be exceeded. The expander is connected to the controller or to another expander using the 30-centimeter connecting cable that comes with the expander.

Weighing approximately 2 pounds and 8 ounces (1.1 kilograms), the D100ERA20 can be mounted either vertically or horizontally in the same enclosure as its controller. The spacing of the units is determined by the connecting cables, which carry high-speed signals. Controllers and expanders may be mounted side by side, using an optional, longer connecting cable. This expander may be mounted with one of two options:  either it can be mounted directly on the panel using screws, or it can be mounted onto a DIN rail. When mounting, ensure that the controller is mounted on top or to the right and the cable connections are made from the bottom. The connecting cables that are used with this module must not be twisted. The D100DER20 CPU’s features include a direct connect message display, a 256 step sequence, and a 128 step shift register, a scan time per 1K of memory in 8 milliseconds with 16 timers and 16 counters, and a memory of 1K RAM, EE PROM or UV PROM.