This document describes the different signal connection schemes that should be adopted while working with NI PCI/PXI-651x 30 V Bank Isolated Industrial DIO boards with high current outputs. This document defines terminology such as sourcing current and sinking current and relates these definitions to your applications using the NI 651x boards. It also provides the pinouts for all the NI 651x boards (with output lines) coupled with examples related to the proper field wiring signal connections. Finally, it describes the main causes for damage to these boards and how to avoid these issues.
The output lines on these boards can either source or sink current to an actuator (or a sensor) depending on the type of actuator. Therefore, different signal connection schemes are required for proper operation.
For devices with current sourcing capabilities, notice how the Darlington Driver is involved in sourcing the current that is flowing through the load.
For devices with current sinking capabilities, notice how the Darlington Driver is involved in sinking the current that is flowing through the load.
Sourcing NI PCI/PXI-6512/6514/6516/6518
Figure 3(a): NI 6512 Pinout
Figure 3(b): NI 6514 Pinout
Figure 3(a and b) shows the pin configuration for the NI 6512 and NI 6514. Please refer to Figure 1 in conjunction with Figures 3a and 3b to conceptualize the actual load connections. Notice that the pinouts for the two devices are different because of the fact that the NI 6514 also supports digital input lines
Figure 4(a): NI 6516 Pinout
Figure 4(b): NI 6518 Pinout
Figure 4(a and b) shows the pin configuration for the NI 6516 and NI 6518. These devices have lower channel counts than the NI 6512 and NI 6514, and support a 37-pin connector instead of a 100-pin connector.
Figure 5 illustrates the actual connections that would be required to drive a sinking load using one of the sourcing devices. The pinout for the NI 6516 has been used for reference and the signal connections would be similar for other sourcing devices.
Sinking NI PCI/PXI-6513/6515/6517/6519
Figure 6(a): NI 6513 Pinout
Figure 6(b): NI 6515 Pinout
Figure 6(a and b) shows the pin configuration for the NI 6513 and NI 6515. Notice how the pin functions change for a sinking and a sourcing output device.
Figure 7(a): NI 6517 Pinout
Figure 7(b): NI 6519 Pinout
Figure 7(a and b) shows the pin configuration for the NI 6517 and NI 6519. These devices are similar to the NI 6513 and NI 6515 in operation, respectively, and differ in the number of available digital lines and the device mating connector.
Figure 8 illustrates the actual signal connections that would be required for connecting a sourcing load to a sinking device. The pinout for the NI 6517 has been used for this illustration and the connections would be similar for other sinking devices.
When used properly (within specifications), the NI 651 x devices are powerful products that provide isolation, high current drive, and up to 30 V digital output signaling. Following are some common misuses that can cause damage to the device. These misuses should be avoided and are not covered by NI hardware warranties which cover only design or manufacturing defects.