Product Safety Alert: Fuses Recommended in NI 651x ApplicationsHardware: Digital I/O (DIO)>>Isolated>>PCI-6516, Digital I/O (DIO)>>Isolated>>PCI-6517, Digital I/O (DIO)>>Isolated>>PCI-6519, Digital I/O (DIO)>>Isolated>>PCI-6518, Digital I/O (DIO)>>Isolated>>PXI-6512, Digital I/O (DIO)>>Isolated>>PXI-6515, Digital I/O (DIO)>>Isolated>>PXI-6513, Digital I/O (DIO)>>Isolated>>PCI-6514, Digital I/O (DIO)>>Isolated>>PXI-6514, Digital I/O (DIO)>>Isolated>>PCI-6513, Digital I/O (DIO)>>Isolated>>PCI-6515, Digital I/O (DIO)>>Isolated>>PCI-6512
Problem: One of the most common failure modes of NI 651x devices that have been returned to National Instruments for repair is damage caused by incorrect wiring - typically a short circuit between outputs and power or ground. Creating this short circuit will damage the board and can result in a fire if the current source is not interrupted. Solution: In order to reduce the chance of damage to the board, and/or damage to the chassis/PC and the surroundings, NI strongly recommends that you install external fuses to prevent excessive current flow. NI 6512/6513/6514/6515 devices NI recommends that a 1.5 A slo-blo fuse be used to protect the power connection for each port. For the 6512 and 6514 boards, the fuses should be placed in the Vcc lines (see figure 1). For the 6513 and 6515, the fuses should be placed in the GND lines (see figure 2). In each case, there are three pins per port on the connector. For most installations, it is sufficient to connect and fuse a single power or ground pin per port. If extremely long custom cables are used, you may wish to connect and fuse additional power or ground pins to reduce voltage drop and heating on the cable. In this case, each line should be fused, with the total current still limited to 1.5 A per port. NI 6516/6517/6518/6519 devices On the 6516/17/18/19 products, the ground or Vcc pins are shared across all output ports. If the total current used for all ports will be less than 1.5A, then NI recommends that a slo-blo fuse rated at 150% of the expected current be used. For the 6516 and 6518 boards, the fuse should be placed in the Vcc lines (see figure 1). For the 6517 and 6519, the fuse should be placed in the GND lines (see figure 2). If the total current for all ports exceeds 1.5A, then each output line should be individually fused (see figures 3 and 4 for the 6516/6518 and the 6517/6519 respectively.  Figure 1: NI 6512, 6514, 6516, and 6518 Connection Diagram  Figure 2: NI 6513, 6515, 6517, and 6519 Connection Diagram  Figure 3: NI 6516 and 6518 Connection Diagram for Current More Than 1.5 A  Figure 4: NI 6517 and 6519 Connection Diagram for Current More Than 1.5 A
For a complete list of affected products see Knowledgebase listed below.
Related Links: KnowledgeBase 4KLCKUNO: Which 651x Products are Affected by the April 2008 Product Safety Alert? Attachments:
Report Date: 04/22/2008 Last Updated: 04/30/2008 Document ID: 4KLB51NO |
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