National Instruments  777687-25 Terminal Block

Part Number 777687-25 is the identifying part number for the National Instruments SCXI-1325 Terminal Block. It is a shielded board featuring 26 screw terminals and is designed to work with the SXCI-1124 input connector. Among the 26 screw terminals, one pair is connected to the SCXI-1124 chassis ground while the other 24 are for signal connection. To use the terminal block with the input connector, the following accessories are required: SCXI chassis, number 1 and number 2 Philips-head screwdrivers, ⅛ in. flathead screwdriver, long nose pliers, wire cutter, and a wire insulation stripper. The 777687-25 offers 250 Vrms channel-to-channel and channel-to-ground isolation. When the device is used with high common-mode voltages, it is necessary to insulate the signal wires for the highest input voltage. Wires of size 26-14 AWG and a rating of 300V and 60 °C are suitable for signals that come in contact with 250V. 

The 777687-25 requires the user to follow certain guidelines for safe operation. First, the module must be kept away from live circuits. Likewise, procedures involving the cover or shield removal must not be performed without sufficient training and all field power must be removed before. Second, the module should only be operated in an Installation Category II as defined by the datasheet. Furthermore, when high voltages (≥30 Vrms and 42.4 Vpeak or 60 VDC),  a safety earth ground wire must be connected to the terminal block safety ground lug. Lastly, the module should be cleaned by brushing off light dust with a soft, nonmetallic brush and other contaminants must be removed with deionized water. 

The recommended temperature range for the operation of the 777687-25 is 0 °C to 50 °C at a relative humidity of up to 5% to 90% RH. Likewise, the device is only meant to be used within a maximum altitude of 2000m. On the other hand, it can be stored at -20 to 70 °C. The device meets the following safety standards for electrical equipment for measurement, control, and laboratory use: IEC 61010-1, UL 3111-1, and CAN/CSA C22.2 No. 1010.1.