LabView Licensing recommendation for cDAQ: NI9426 Open Connector Pulse and NI9213 Temperature Alarm

Question

I am completely new to LabView/DAQ (normally a technical engineer and programmer).

Last year my company has bought National Instruments hardware in a rush to get a project up and running.

DAQ Hardware:

• 1x NI cDAQ-9188 CompactDAQ 8-Slot Ethernet Chassis
• 1x NI 9426 32-Channel, 24 V, 7 µs Sourcing Digital Input Module
• 2x NI 9213 16-Channel Thermocouple Input Module
• 2x NI 9205 32-Ch ±200 mV to ±10 V, 16-Bit, 250 kS/s Analog Input Module

Sensors:

There are three type of sensors attached to the hardware.

• 24 Liquid Level sensors attached to NI9205 (voltage/resistance)
• 24 Thermocouples attached to NI9213 (K-type)
• 24 Pressure sensors attached to NI9205 (voltage/resistance)
• 24 Flow rate sensors attached to NI 9426 (open collector 263 pulses per liter)

Most sensors are simply collecting data, there is no real processing involved with one exception of issuing an alarm (if the temperature exceeds a set value).

What we do right now is:

• Logging of liquid level of different machines
• Logging of temperature (and issuing alarm when temp to high)
• Pressure not logged at this moment (was used during development stage but no longer required)
• Flow rate not logged at all at this moment (but this will be needed and the major headache)

For almost everything (less the alarms), the free license of LabView Signal Express seems to suffice.

Flow Rate:

What is missing is logging of the flow rate. This seems to require a license of LabView, since the NI 9426 doesn't actually count pulses and a program has to be written. LabView Signal Express apparently can't log to text files in real time (correct me if I am wrong) and I am struggling to export logs in batch mode with my little knowledge and time.

Datasheet of the flow meter is here: http://www.digisavant.com/PDF/FS-4400H-Spec.pdf

A preliminary program has been made for the trial version of LabView (VI), but the person who did it is no longer available. It has shown that the sensors and the NI hardware can do that job, but that's about it.

Current Licenses (Trial):

LabView and LabView Signal Express are both available with a trial license that will run out in a week or two. The trial license of LabView Signal Express running out will effectively disable the alarms since this is a feature of the FULL license. The license of LabView running out will not do anything, since it's not even installed at this point.

Having these licenses running out means we have to purchase something very soon. And exactly this is my problem.

If I recommend to my company to buy the Signal Express, we are paying $999 just to have what we have right now with the alarms. But I am still not sure if it could handle the flow rates in real time or through the logs.

If I would go with LabView Full (?) it would cost $ 2,699 (or the equivalent plus a little more in my currency, since we are in Asia).

As you can tell, I am really confused with all the options. But from now on I will make DAQ my own and clean up the mess and do the right thing.

Here are my questions:

• What license would you recommend for our situation? Please keep in mind that we only plan to do simple things.

• Would I be able to work around the alarms with a free version of LabView Signal Express?

• Would an external person with a full LabView license and LabView knowledge be able to provide an EXE file that does what we need without the need to buy an extra license?

Answer 1

Although SignalExpress is quite limited, it can do real-time logging. There are at least two ways you can do it. One is to include a step in your project that logs to file. Another is to turn on the default logging. The latter method produces a tdms file, which is quite a convenient file structure, as it's binary (therefore fast), and you can download a plugin for Excel so you can import the data into Excel.

I do not know if SE can do the counting you require. It can do some limited signal processing such as add one signal to another in the Full license. Alarms are also available only in the Full license.

The LabVIEW code generation feature, IIRC, is pretty poor. The quality of the code generated is not that great, as it uses a lot of Express VI's, without the scalable architecture underneath you need.

SE is a quick-and-dirty solution that works for very basic DAQ. If you introduce even moderately complex control, it won't deliver.

My recommendation is to start from scratch with LabVIEW. Use a scalable architecture like producer-consumer, and you'll be fine.

Answer 2

The Base Package of LabVIEW will be adequate for what you want - assuming you're on Windows - but if you want to turn your LabVIEW program into a standalone executable file, rather than continuing to run it inside the development environment, you would also want the Application Builder. If you can afford that combination and you are happy to write some LabVIEW code, that will be the most flexible solution for you and good value in the long run, because you can build and distribute as many applications as you want with no further licence costs.

If you need more time with the LabVIEW trial licence to make your decision, contact National Instruments - they may well give you an extension if you explain what you need. Also, they will be able to suggest suppliers who can do LabVIEW development for you if that's the way you would prefer to go.