D2000M series Intrinsically Safe Multiplexing System consists of one to four Analog-Temperature Multiplexer units model D2010M, up to twelve Expander units model D2011M, or up to four Digital Multiplexer units model D2030M, mounted in Hazardous Area/Hazardous Locations Zone 1-2, Gas Group IIC-IIB-IIA T4 or Class I, Division 1-2, Group A, B, C, D T4 and connected via a single/redundant 2 wires data communication/supply line to a Modbus Gateway unit model D2050M, mounted in Safe Area/Non Hazardous Locations and connected to a PLC, DCS or PC. Multiplexer Expander D2011M units can be installed in the field, close to input sensors, for data acquisition of signal from Hazardous Area/Hazardous Locations Zone 0-1-2 or Class I, Class II, Class III, Division 1-2. The units are primarily intended for Hazardous Area/Hazardous Locations acquisition of low level signals from mV, thermocouples, thermoresistances or mA (via external shunt device like D1090Q four channel shunt resistor) sources. D2011M scans all channels using state of the art solid state isolated relays, and stores all data in the D2010M memory buffer connected to it, where they can be rapidly accessed by the Modbus Gateway D2050M unit. Each D2011M unit accepts directly up to 16 input channels. An integrating type, high rejection, high accuracy (18 bits) A/D converter installed on D2010M unit that control up to three Expander D2011M, provides accurate and stable measurements. All parameters are software configurable by serial commands via D2050M Gateway unit and stored in the D2010M unit connected to the Expander.