Product Introduction

The NI TB-2605 is a high-precision isothermal wiring terminal block, specifically designed to be used with the PXI-2501 and PXI-2503 multiplexing switch modules. The device features an integrated isothermal design, with a sealed enclosure that can prevent airflow from affecting the temperature, effectively reducing the temperature difference between each wiring terminal. The body is equipped with a high-precision thermistor, which can achieve the cold end temperature compensation required for thermocouple measurements. The overall design is a screw wiring form, mainly used for the front-end conversion of thermocouples, thermal resistors, thermistors, and various low-level voltage signals, significantly improving the overall accuracy of weak signals and temperature measurement. 

Model Interpretation

TB is the abbreviation for terminal block in English, indicating that this product is a wiring terminal accessory. 2605 is the exclusive series number of the product, corresponding to the dedicated terminal blocks with isothermal structure and cold end compensation function under the NI brand, mainly serving the high-precision temperature measurement scenarios of PXI switch modules. Technical Specifications

This terminal platform is only compatible with the PXI-2501 and PXI-2503 switch modules. It can connect thermocouples, thermoresistors, thermistors, as well as single-ended and differential low-level voltage signals. The built-in thermistor serves as a cold-end compensation device, with a temperature measurement accuracy of ±0.5 degrees Celsius within the normal working range, and a repeatability error controlled at ±0.2 degrees Celsius. The overall structure achieves isothermal effect, suppressing temperature gradient changes in the terminal area, and the housing can prevent temperature fluctuations caused by external air currents. The screw-type terminal connectors are suitable for conventional single-strand and multi-strand wires. The maximum common-mode voltage of the single-channel signal superposition does not exceed 30 volts RMS AC or 60 volts DC. The equipment operates within a temperature range of 0 to 55 degrees Celsius, has a storage temperature range of -20 to 70 degrees Celsius, maintains a relative humidity of 10% to 90% in the operating environment, and does not allow condensation during operation. The product is constructed with flame-retardant circuit boards, metal terminal screws, and insulated housings, featuring excellent vibration resistance and corrosion resistance.

Interface and Communication Configuration

The rear of the device has a dedicated interface for direct insertion into the front panel interfaces of the PXI-2501 and PXI-2503 modules, making installation convenient without the need for additional adapter components. Multiple groups of screw terminal connectors are arranged on the front to connect external sensors and signal sources. Two groups of analog bus interfaces are set at the front, enabling bus interconnection of multiple switch modules with the help of matching connectors, thereby expanding the system's acquisition channels. This terminal platform is an inductive hardware accessory and does not have an independent communication circuit or control chip. It only performs physical signal conversion and relies on the accompanying PXI module and NI-DAQmx driver program to achieve data transmission and functional control, and is compatible with mainstream test development software.

Core Functions

The built-in temperature sensing element collects the temperature of the terminal area in real time, providing precise cold-end compensation for thermocouple measurements, effectively eliminating measurement errors. The integrated isothermal structure combined with a sealed housing reduces signal drift caused by environmental air currents and local temperature differences, stabilizing weak signal transmission. One device can be compatible with multiple temperature sensors and low-level voltage signals, simplifying the setup process of multi-type test systems. The screw terminals are securely connected and do not loosen during operation. The analog bus interfaces support multi-module cascading, enabling flexible expansion of channel numbers and meeting high-channel acquisition requirements. The overall structure is stable and is suitable for long-term continuous operation in laboratories and industrial sites. Applicable scenarios

Mainly used in multi-channel high-precision temperature acquisition systems, including multi-point temperature measurement in industrial sites, laboratory temperature instrument calibration, environmental monitoring, etc. It can be used as a front-end wiring device to complete the conversion and acquisition of low-level signals such as strain signals and microvolt-level voltages, and is suitable for working environments with electromagnetic interference. Widely used in automated test platforms based on PXI architecture, combined with corresponding switch modules, to achieve cyclic scanning and monitoring of multiple temperature and electrical signals.

Usage and Maintenance Instructions Instruction Manual

Before installation, it is necessary to turn off the power supply of the entire PXI system. Align the terminal block with the front interface of the switch module and insert it smoothly to ensure a proper connection. Complete the wiring according to the signal type and terminal markings. After connecting the wires, tighten the screws to avoid poor contact. When using thermocouples for measurement, enable the cold junction compensation function in the accompanying software and complete the temperature correction using the built-in sensor. When expanding the multi-module channels, connect adjacent modules through the analog bus interface to ensure reliable line connection. During use, strictly adhere to voltage limits and avoid connecting high-voltage signals beyond the specifications.

Maintenance Instructions

The operating and storage environment of the equipment must be kept dry and ventilated, away from dust, corrosive gases, and strong electromagnetic interference sources, and the environmental temperature and humidity should be maintained within the rated range. Regularly check if the wiring screws are loose, if the insulation layer of the wires is damaged, and if there is any oxidation on the terminal surface. If any problems are found, immediately cut off the power supply and handle them. When cleaning the equipment, cut off the system power supply, use a dust-free soft cloth to wipe the surface and terminal connections, and do not use liquid cleaners to directly contact the components. When the equipment is idle for a long time, remove the external connection cables, place the terminal block in a cool and dry place for proper storage, and avoid squeezing and severe impacts.