OPT2091 accessory consists of a Cold Junction Compensator resistance kit to be used with D2010M, D2011M analog/temperature input multiplexer units.
These units, when programmed for acquiring temperature inputs from Thermocouple Sensors, have a choice of selecting fixed or automatic compensation.
The latter is accomplished by inserting OPT2091 option directly on channel 16. One OPT2091 provides cold juction compensation for all channels (up to 15) of the unit on which it is installed.
See data sheet of D2010M/D2011M or D2000M instruction manual for more details.
OPT2091 is provided already mounted on blue terminal block.