National Instruments VXI-TB-1303 Isothermal Terminal Block

The VXI-TB-1303 is an efficient Isothermal Terminal Block. The manufacturer of the VXI-TB-1303 is National Instruments. The VXI-TB-1303 is used to connect to a VXI-SC submodule. A special feature of the NI VXI-TB-1303 is the minimum level of temperature gradients across its screw terminals while taking measurements using thermocouples. For this purpose, the Terminal Block is equipped with an isothermal copper plane and a temperature sensor. The sensor used in the VXI-TB-1303 is a thermistor cold-junction temperature sensor with high accuracy.  

The National Instruments VXI-TB-1303 is a 32-channel Isothermal Terminal Block. The VXI-TB-1303 is equipped with 80 screw terminals. These screw terminals make it easy to connect the device. These terminals are used for different purposes. 32 pairs of the screw terminals are connected to the 32 different input connections of a VXI-SC submodule. Four terminals of the NI VXI-TB-1303 Terminal Block are tagged as GND and are connected to the ground pins of the chassis housing the VXI-SC submodule. The remaining screw terminals are kept free and are reserved for any additional VXI-SC submodules, which may be required to be connected in the future.

This Terminal Block incorporates a pull-up resistor and a ground-reference resistor. The pull-up resistor of the VXI-TB-1303 connects the Ch+ channel with +5 V. The pull-up resistor detects the output saturation of the amplifier of a VXI-SC submodule. In this way, open thermocouples can be detected and identified. The ground-reference resistor of the NI VXI-TB-1303 is inserted between CH- and chassis ground channels. This ground-reference resistor provides the reference to the floating thermocouples with respect to ground.

VXI-TB-1303 Obsolete Status has been announced by National Instruments, but the terminal block will still be available for purchase and repairs by Apex Waves.