Best Device for Control and Data Acquisition

[nathan.page]

Hello All,

I am looking for the best NI device to use in a control and data acquisition system. I am upgrading a test stand that previously used a Siemens PLC for control and an HBM MGCplus for data acquisition. These were two separate systems. My goal is to find a device that can perform both functions (control/monitoring and data acquisition) to reduce the size and complexity of the system. 

The primary constraint is that the control system must be able to run stand alone continuously due to our test lengths. We have 100+ hour tests for our products, so the device must be able to continuously monitor and control the system during the entire length of the test. The UUT is a hydraulic pump which is connected to an electro-hydraulic system . The device I'm looking for will control/monitor and acquires data from this electro-hydraulic system. 

Any ideas would be great and I appreciate the help! 

[crossrulz]

If it were me, I would be heavily looking at the cRIO platform.  The cRIO is based on a Linux RT controller with an FPGA backplane.  You then choose modules to put into the controller depending on your IO requirements.  You will need LabVIEW RT and LabVIEW FPGA modules in order to program the cRIO.

[AndyClegg · Accepted solution]

Yes CompactRIO probably best option, but really depends on the detail, and how far you want to take you LV development journey.

CompactDAQ - ideal for data acquistion, and can do some basic control (e.g. logic-based), can be simpler to programme if you are unfamiliar with LabVIEW, DAQmx functions provides some easy to use functions to build data acquisition applications.

CompactRIO - can do job of CompactDAQ but with much more flexibility, deterministic high speed control. Can be a bit more involved with programming - you will need LabVIEW RT (real-time) for the basic applications Some CompactRIO are compatible with DAQmx, but even building data acquisition with core LabVIEW isn't challenging (especially if you start with one of the pre-build example archiectures close to what you need). Just need to be more aware of timing when building applications, but that can only get complicated if your application involved multiple threads/loops or data coming in from lots of different places and processing on the fly. LabVIEW FPGA is a higher level of complexity (but again starter examples help), but you may not need that - typically used for v.fast signal processing or an independent bit of functionality (e.g. safety/watchdog).

CompactRIO is also well suited to headless operation - i.e. does not need a PC permanenty connected - and some have buit in display interfaces so you can have a UI / screen without having to resort to a separate device for that. There is a difference between a compactRIO chassis and a compactRIO controller - with the former much more like a cDAQ in regards to this aspect.

We've built test rigs using both cDAQ and cRIO - if it is more of an experimental system (somebody and PC always there) and where the customer may want to change functionality we may suggest cDAQ, but if need something more robust (e.g. 24/7 operation, unmanned) or fast control then it is cRIO.

[nathan.page]

Thanks for the quick reply and information! It looks like the cRIO platform is the best option for our application.

[nathan.page]

Thank you for the detailed response! We definitely need headless operation for the control and monitoring so the cRIO sounds like the better option. 

Just out of curiosity, what about the PXI chassis with a RT controller? Would that be basically the same as cRIO except with more channels and/or better hardware?

[crossrulz]

---

@nathan.page wrote:

Just out of curiosity, what about the PXI chassis with a RT controller? Would that be basically the same as cRIO except with more channels and/or better hardware?

---

A high channel count would make me look at going with the PXI route.  I'm not convinced about the "better hardware" part of your observation.

[AndyClegg]

If you have high channel counts have you considered the physical layout, as it may be that some sort of distributed IO may offer a neater / easier to maintain system, rather than having everything wired into a central location. Though I presume you are just looking at replacing the PLC and existing data acquisition. rather than redoing the wiring.

When we looked at PXI for one of the bigger test rig systems, we found the PXI IO modules a less than perfect fit - sometimes the lowest spec modules were much higher than needed and also a lot of unused channels.

Maybe best to do a side-by-side comparison of cost / IO options between cRIO and PXI.

[Clint1000]

Is this thread still open??  I was pointed to this discussion from one of my questions in another thread.  

if it is open..you said:

CompactDAQ - ideal for data acquistion, and can do some basic control (e.g. logic-based), can be simpler to programme if you are unfamiliar with LabVIEW, DAQmx functions provides some easy to use functions to build data acquisition applications.

I come from a PC based LABVIEW PXI environment.  I'm trying to monitor a number of transducers ( yet to be picked out).  Knowing LV would LV RT be relatively easy to learn?  Or should I stick to LV and Compact DAQ?

CompactRIO - can do job of CompactDAQ but with much more flexibility, deterministic high speed control. Can be a bit more involved with programming - you will need LabVIEW RT (real-time) for the basic applications Some CompactRIO are compatible with DAQmx, but even building data acquisition with core LabVIEW isn't challenging (especially if you start with one of the pre-build example archiectures close to what you need). Just need to be more aware of timing when building applications, but that can only get complicated if your application involved multiple threads/loops or data coming in from lots of different places and processing on the fly. LabVIEW FPGA is a higher level of complexity (but again starter examples help), but you may not need that - typically used for v.fast signal processing or an independent bit of functionality (e.g. safety/watchdog).

CompactRIO is also well suited to headless operation - i.e. does not need a PC permanenty connected - and some have buit in display interfaces so you can have a UI / screen without having to resort to a separate device for that.

Regarding that statement..How does the user interact ( if thats needed) if a PC isn't connected permanently ?? If I'm using COMPACT RIO I hook up a keyboard and monitor to the controller, program my application in LV RT then disconnect it ??  When the controller is powered up my application starts running??  Correct?

There is a difference between a compactRIO chassis and a compactRIO controller - with the former much more like a cDAQ in regards to this aspect.

Don't understand this statement.  Aren't you comparing "apples to oranges"??  Isn't a chassis something the controller plugs into??  Much like a PXI8101 plugs into a PXI1062??

Thanks!