National Instruments 781420-17 Matrix Switch Card

The National Instruments 781420-17 (Model Name: NI 2817A) is a high density matrix switch card designed to integrate into the NI SwitchBlock platform. This allows scalable switching configurations when combined with other cards. The card is particularly useful for creating complex switching networks in test systems and providing users with the flexibility to configure multiple paths between test points and instruments. This modular design feature allows users to combine several NI 2817 cards to build a customized multicard switch configuration that meets specific testing needs. 

Each channel of the 781420-17 card is designed to handle a maximum switching voltage of 100 V with a current limit of 0.25 A per channel and a maximum switching power of 3 W. This makes it suitable for applications requiring reliable switching of low power signals. The maximum carry current is slightly higher at 0.3 A per channel. The card offers a mechanical relay life of up to 2.5 × 10^8 cycles.The DC path resistance of this matrix switch card is kept low at the start less than 1.6 Ω and increases to greater than 2.6 Ω at the end-of-life. The open channel resistance exceeds 1 × 10^9 Ω effectively isolating the switched-off pathways to minimize interference or signal leakage. This isolation capability is complemented by isolation values that range from 65 dB at 10 kHz down to 30 dB at 1 MHz. 

The 781420-17 card supports the simultaneous operation of up to 61 relays with relay operate and release times ranging from <1 ms for up to 8 relays and <2 ms for up to 50 relays. This offers a fast response for rapid switching applications. With a bandwidth of 5 MHz, it supports a wide range of analog signal frequencies. Power consumption for the NI 781420-17 card is optimized with each relay consuming 63 mW and an overall power consumption limit of 3.9 W. The card’s compact form factor of 11.2 cm × 1.2 cm × 17.1 cm and 320 g weight makes it suitable for integration into space-limited setups. The Reed relays used in the card ensure low contact wear further extending the card’s operational life.