SC Express Physical Channels
- Updated2024-10-22
- 2 minute(s) read
SC Express Physical Channels
In physical channel names, PXI1Slot1 is the default device name for SC Express devices, where PXI1 is the chassis number, and Slot1 refers to the slot number. You can change these names in MAX.
Analog Input
SC Express Devices have from four to 32 analog input channels. A 4-channel device has physical channels ranging from PXISlot1/ai0 to PXISlot1/ai3, an 8-channel device has physical channels ranging from PXISlot1/ai0 to PXISlot1/ai7, and a 32-channel device has channels ranging from PXISlot1/ai0 to PXISlot1/ai31.
You can use channels from multiple analog input SC Express devices in the same NI-DAQmx task.
Analog Output
NI 4322 devices have eight analog output channels ranging from PXI1Slot1/ao0 to PXISlot1/ao7. You can use channels from multiple analog output SC Express devices in the same NI-DAQmx task.
Strain and Wheatstone Bridge Measurements
The NI 4330 and 4331 devices support only the AI Strain Gage, AI Force Bridge, AI Pressure Bridge, AI Torque Bridge, AI Bridge (V/V), and AI Custom Voltage With Excitation channel types. The NI 4339 supports AI Voltage in addition to the previously mentioned measurement types.
When using NI 4330 and 4331 devices with an AI Custom Voltage With Excitation channel, you must set the AI.Excit.UseForScaling attribute/property to true. This attribute/property causes the channel to return ratiometric data: Vin/Vex. These devices perform this division in hardware. The NI 4339 does not require the AI.Excit.UseForScaling attribute/property. Disabling this property allows for the NI 4339 to perform voltage measurements while providing voltage excitation.
NI 4330 and 4331 devices return a voltage ratio rather than a voltage. Therefore, use the AI.Bridge.InitialRatio attribute/property to specify the initial voltage ratio, or set the AI.Bridge.InitialVoltage attribute/property to the ratio Vin/Vex returned by the device, multiplied by Vex.