This is a pair of DGH D1252M modules, an analog current input module made in the USA by DGH Corporation. Specifically, it's designed to accept a 4-20mA current loop signal u2014 the industry-standard range used widely in industrial process control for sensors like pressure transducers, flow meters, and level sensors.
It communicates over Modbus RTU, a common serial communication protocol used in industrial automation and SCADA systems. The terminal block on the side provides connections for the analog input (u00b1IN), digital I/O lines (DI0, DO0, DO1), power supply (+VS/GND), and the RS-485 data lines (Y/G).
These items are likely used.
1 in stock at Habitat for Humanity of the St. Vrain Valley ReStore