National Instruments 777687-22 Temperature Sensor Terminal Block

Part Number 777687-22 is the identifying part number for the National Instruments SCXI-1322 Temperature Sensor Terminal Block. The 777687-22 features a shielded board with 48 screw terminals that allows easy connection to the SCXI-1122 input connector and out of these 48, 16 pairs of screw terminals connect to the SCXI-1122 module inputs. The rest of the 7 pairs of screw terminals are used for the module excitation channels.

The 777687-22 has a cold-junction sensor whose output value ranges from 1.91 at 0 °C to 0.58 V at 55 °C. Likewise, the accuracy of the sensor is 0.65° from 15 to 35 °C 0.85° from 0 to 15 °C and 35 to 55 °C while the repeatability is 0.4° from 15 to 35 °C. Furthermore, the terminal block has a common-mode isolation of 250 Vrms between terminal-to-terminal and 480 Vrms between terminal-to-earth. The module has an operating temperature of 0 to 50°C and a storage temperature of -20 to 70 °C. The recommended relative humidity for the operation of the temperature sensor terminal block is 5 % to 90 % noncondensing. Likewise, it is recommended that the terminal block be operated within a maximum altitude of 2000 m. 

The 777687-22 is designed for electrical measuring and test equipment safety as per IEC 61010-1, UL 3111-1, and CAN/CSA C22.2 No. 1010.1. The terminal block is cleaned by brushing off light dust with a soft, nonmetallic brush while deionized water is used to remove other contaminants. Note that the block must be completely dry and free from contaminants before it is put to use. To use the 777687-22 with the SCXI-1122 input connector, first, signal wires are connected to the terminal block. This is done by stripping about 7 mm (maximum) of insulation from the signal wires and connecting them to the screw terminals by tightening them to a torque of 5 to 7 in-lb. The SCXI module front connector and the terminal block are then linked by matching the mating connection on the terminal block to the module front connector.