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The NI cDAQ-9174 and cDAQ-9178 chassis represent the next generation of NI CompactDAQ USB data acquisition systems. These two chassis build on the original feature set of NI CompactDAQ by incorporating user feedback and the latest technology from NI data acquisition, NI-STC 3 technology.
New Physical Features
Because of reduced physical component space needed by NI-STC 3 technology, users have two chassis options for NI CompactDAQ systems: the 4-slot cDAQ-9174 and the 8-slot cDAQ-9178. The chassis are made of the same grade of A380 aluminum for added ruggedness. The most notable physical difference in the 8-slot chassis is the addition of two front BNC connectors for external clocks and triggers. These triggers make it easier to synchronize an NI CompactDAQ system with external devices or systems.
Figure 1. NI CompactDAQ has two new options for mixed system development.
Several NI CompactDAQ systems are deployed in environments more rugged than a lab or engineering benchtop. The cDAQ-9174 and cDAQ-9178 chassis were designed with this in mind and offer an improvement on the USB cable strain relief with a captive USB cable. This special USB cable, which connects much like a VGA monitor cable, is included with the chassis. To make it easier to use alternate power supplies, both new chassis also offer the option of screw terminals for the power connection. The power supply is shipped with a connector already wired for simple setup, but it is also shipped with an empty connector plug with open screw terminals for alternate power supply use. The image below shows some of the new physical features of the cDAQ-9178.
Features include:
- Strain relief from the USB cable
- BNC trigger lines1
- Three status LEDs
- Screw terminal power connector
1This feature is only on cDAQ-9178
Visit the NI CompactDAQ chassis model page for prices and ordering information.
Multiple Timing Engines for Multiple Acquisition Rates
With the cDAQ-9174/78 chassis, you can install a thermocouple module next to an accelerometer measurement module and acquire from both simultaneously at different rates. The cDAQ-9174/78 chassis have multiple analog input timing engines, which means you can group all of your analog input modules in up to three sets of modules. These sets, known as tasks, can all run at different rates because each one has its own timing engine in the chassis backplane. This alleviates the need to decimate or parse lower-speed data from the higher-speed data as you need to do in the original cDAQ-9172 chassis. Figure 2 shows a screenshot of a LabVIEW program that acquires from multiple modules at multiple rates.
Figure 2. This image shows different AI tasks running at different rates in the same chassis.
With the original cDAQ-9172, there were no digital input or output timing engines requiring the use of another subsystem such as a counter or analog clock. This type of digital task is referred to as being correlated. The cDAQ-9174/78 chassis now provide the ability to use internal timing, inherent to the digital task, to run digital input or output as hardware timed. This leaves more resources open to perform other operations in parallel. Table 1 lists some of the benefits associated with the multiple timing engines and NI-STC 3 technology.
| Features | Benefits |
| 3 AI Timing Engines | Run multiple AI tasks at different rates |
| 1 DI Timing Engine | Run DI task without external clock |
| 1 DO Timing Engine | Run DO task without external clock |
| 1 AO Timing Engine | Run AO task without external clock |
Table 1. Simultaneously run all different systems with the new chassis.
Visit the NI CompactDAQ Advisor to configure your NI CompactDAQ system based on the cDAQ-9174 or cDAQ-9178.
Advanced Counter Functionality from NI-STC 3 Technology
The original cDAQ-9172 chassis has two counters. However, the cDAQ-9174/78 chassis now have the new feature of four, full-function 32-bit counters. These counters are inherently different from the counters in the cDAQ-9172 chassis in that each now has its own embedded counter. These improved counters make it possible to run many advanced counter tasks using one counter instead of cascading two. The cDAQ-9174/78 chassis can now output finite pulse trains with the use of only one counter. Table 2 highlights some of the new benefits of the counters from NI-STC 3 technology.
| Features | Benefits |
| Four counters | Multiple counter tasks compare to two onboard counters on the previous cDAQ-9172 |
| Separate counter for correlated DIO | Saves counter usage |
| Buffered sample clock frequency measurement with one counter | Saves counter usage |
| Route DIO and PFI line to any slot | Can do correlated DIO in any slots compared to previous cDAQ-9172, where it can be done only in slots 1 and 4 and PFI lines from 5 and 6 |
Table 2. This table lists some of the new benefits of counters from NI-STC 3 technology.
For more information on NI CompactDAQ, see the Product Overview.
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Configure your system with the NI CompactDAQ Advisor
View pricing and purchasing information on the NI CompactDAQ chassis model page
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