Data acquisition device product question

[vepa]

I was looking for a multifunction data logger (for temperature, pressure, flow sensors) that can also, based on the reading, generate an output which can be used by a switch to control other equipment. Does NI have such a product?

[santo_13]

NI has a lot of products that fit your description. More descriptive requirements would help the forum members to suggest better DAQ choices.

To provide a better analogy, your requirement is as simple as my phone should have a touch screen, able to make calls, send messages.

[vepa]

So I am looking for a system with 16 analog input channels (for thermocouple, pressure sensor, and flow sensors). A BNC connector for pH sensors would be great if built in the system. at least 2 pulse counters for flow sensors, and at most 16 digital I/Os that can be configured as output that can be set based on reading of the sensors. A 100kS/s to 1MS/s sampling and at least 16 bit ADC.

Built in signal conditioning for thermocouples and pressure sensors would be great if there is a system like that from NI.

[santo_13]

Do you have any budget in mind?

Few things to consider,

• Low-cost DAQ are purely +/-10V range input AI
  • This is undesirable for Thermocouple, 4-20mA current loop sensors such as pressure/flow sensors
• There are dedicated DAQ models for Thermocouple and current loop sensors/actuators
• Most DAQ come with at least 8 DIO lines operating at 3.3V/5V logic levels
• 100kS/s - 1MS/s seems reasonable but not for thermocouples, these tend to be pretty slow typically < 100S/s

General recommendation would be towards cDAQ modules but if restricted by budget could be simple USB-DAQs

cDAQ is more robust, flexible and incorporates signal conditioning for Thermocouples and current loop sensors.

[vepa]

Thank you for the information! Yes, I have a budget of under $2000, and a PC connected DAQ is preferred. Sorry for not putting that in in previous post.

For your note on +/- 10V for thermocouple being undesirable, why is that the case? Does the voltage go above these thresholds?

[crossrulz]

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@vepa wrote:

For your note on +/- 10V for thermocouple being undesirable, why is that the case? Does the voltage go above these thresholds?

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It is more of a resolution issue.  Therocouples output in the <100mV range.  So a 100mV across a 10V range and you are using less than 1% of the range of the A/D.  This can be compensated for if you find signal conditioners to bump up the voltage range of the TC.

[vepa]

I see, so will something like USB-6003 work? I know it does not meet all specs I listed but the most important thing is in SW I can set the output based on reading values of sensors connected as input. What do you guys suggest?

[santo_13]

USB-6212/6216 likely fits your requirements better.

USB-6003 is a very basic DAQ and, may not meet all your requirements.

[vepa]

Ok,  how would you recommend connecting a pH sensor and thermocouple to these loggers like will I need to buy signal conditioning hardware for the sensors?

[santo_13]

pH sensor, you definitely need a signal conditioning circuit. (https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MsvSAE)

Thermocouple, it would be best to have a signal conditioning circuit with CJC too.

I hope all the sensors or signals you plan to use are 5V logic (digital) and +/-10V max range and not 12/24V, if so, you need a voltage translator too.