04-11-2018 02:09 AM
I am very much a novice in the field of data acquisition systems, therefore i have a series of questions related to a setup that i have 'inherited' from a previous postgraduate. The setup consists of a cDAQ 9174 with three modules; 1 x NI9237 (with NICB-37F-LP D-sub terminal block attached) and 2 x NI9211 modules.
I wish to acquire data from 4 x Kistler 6152A mould cavity pressure sensors, is it a case of soldering each pressure transducer to the NICB-37F-LP? How many pressure transducers can be attached to the terminal board if it is 37 pin? Is the NI9237 module able to power all four transducers? Does the analogue signal need to amplified and converted to a digital signal?
Similarly with the NI9211 modules, i would like to measure melt temperature using 4 x type k thermocouples. Is it just a case of directly wiring each thermocouple to one module, as from my understanding each module can accommodate up to four thermocouples?
For context, the set up is going to be used to monitor key process variables within an injection moulding unit.
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04-12-2018 01:59 AM - last edited on 11-21-2024 10:11 AM by Content Cleaner
@aje864 wrote:
I wish to acquire data from 4 x Kistler 6152A mould cavity pressure sensors, is it a case of soldering each pressure transducer to the NICB-37F-LP?
How many pressure transducers can be attached to the terminal board if it is 37 pin? Is the NI9237 module able to power all four transducers?
Does the analogue signal need to amplified and converted to a digital signal?
I don't think so. A NI-9237 is meant for measuring the resistance of up to four strain bridges. That's a component that has a specific resistance that changes slightly under load (https://www.ni.com/en/shop/data-acquisition/sensor-fundamentals/measuring-strain-with-strain-gages.h...). As far as I can see from the datasheet, the Kistler 6152A outputs an electric charge(?) (http://www.helmar.com.pl/helmar/plik/6152_nn3934.pdf). The datasheet does not state exactly what the sensor output is, so I don't know if there is a way to measure the sensor directly. However Kistler has an amplifier that converts the sensor's charge to a voltage. There are many modules available for CompactDAQ that can measure voltage.
(Edit: I found that Kistler produces a Charge Amplifier Module for CompactRIO; it should normally work in CompactDAQ as well. Have a look at https://www.ni.com/en/support/documentation/supplemental/06/compactrio-third-party-products-complete... and https://www.kistler.com/en/products/components/signal-conditioning/charge-amplifier-module-ki-5171a-... )
@aje864 wrote:
Similarly with the NI9211 modules, i would like to measure melt temperature using 4 x type k thermocouples. Is it just a case of directly wiring each thermocouple to one module, as from my understanding each module can accommodate up to four thermocouples?
Yes, that is correct. The NI-9211 supports four thermocouples (https://www.ni.com/en-us/shop/model/ni-9211.html).
04-12-2018 02:21 PM
So as i understand it, the NI-9237 module is not able to receive a current signal directly from the pressure transducer so it would normally go via an external amplifier? However now you can use a charge amplifier module (Kistler 5171A)? What exactly is the NI-CB-37F-LP used for that is attached to the NI-9237?
And you can wire the K type thermocouples directly to the NI-9211 module?
Thank you very much for your reply, it is extremely helpful
04-13-2018 02:24 AM - last edited on 11-21-2024 10:12 AM by Content Cleaner
@aje864 wrote:
And you can wire the K type thermocouples directly to the NI-9211 module?
Yes, you can do that! You can find this information in the NI 9211's Datasheet on page 6. Be aware that you need to wire the thermocouples directly to the NI-9211, not putting any other material types extending cables inbetween (correct thermocouple extension are okay). The NI-9211 even has cold-junction compensation (it measures the temperature of the connector block and therefore knows the temperature of the cold-junction).
@aje864 wrote:
So as i understand it, the NI-9237 module is not able to receive a current signal directly from the pressure transducer so it would normally go via an external amplifier? However now you can use a charge amplifier module (Kistler 5171A)?
Maybe I don't understand how the Kistler 6152A's works, but as I understand they produce a small charge that can be measured. Like a small capacitor that has a charge and you want to know how big the charge is.
On the other hand the NI-9237 outputs a set voltage and measures the resistance of a connected bridge, that is something different. Yes, as I understand from Kistler's homepage, they make amplifiers that shall be used with the 6152A's. Have you used the 6152A's before? There might be another way to use them!
@aje864 wrote:
What exactly is the NI-CB-37F-LP used for that is attached to the NI-9237?
The NI-CB-37F-LP is basically a breakout box, making it easier to manually wire things to a module with D-SUB connector. I used them in lab a lot as it is easy to change the connections a lot. A more ruggedized solution is creating a cable with a D-SUB connector as well and having fixed, soldered connections.
04-16-2018 08:32 AM
Thank you ikaiser!!
04-17-2018 06:24 AM