SCXI Hardware Configuration Conflict

[OKors]

I’m hoping someone can help me confirm a necessary hardware change with our current SCXI unit.

Here's our current hardware setup:

• SCXI- 1000 Chassis
• SCXI- 1520 Bridge Board w/ 1314 Terminal Block
• SCXI- 1180 Feedthrough Panel w/ 1302 Block
• SCXI- 1349 Cable Adapter
• PCI DAQ Card  

I was trying acquire a +/- 10v signal through the SCXI- 1180 Feedthrough Panel and have it recognized by the DAQ board. It appears that the 1349 Cable Adapter originally purchased is not the correct one for what we need. Based on this Knowledge Base Article the 1349 adapter does not free up the necessary channels needed to acquire an external analog signal. From what I understand we need a SCXI- 1346 adapter?

I’d like to confirm that this is what we need before the purchase is made and was hoping someone could help verify this for me.

What we’re looking to do is acquire typical strain data using the above mentioned bridge board and terminal block, but also read two channels of signal coming from our hydraulic controller (MTS-407). The controller outputs are a simple +/- 10v signal (LVDT and LoadCell signal, pre-conditioned and calibrated at the controller). My understanding is that we could use the differential amplifier inputs of the feedthrough panel to read this signal- but again our main issue seems to be in our current 1349 Cable Adapter not freeing up the necessary channels on the DAQ board to read the feedthrough panel in the first place.

So please confirm, if I understand this correctly we need to purchase the SCXI- 1346 adapter to read external signals from the Feedthrough panel?

Thank you for your time,

[Russ@Davis]

I don't believe the 1349 is the issue.  The 1346 is intended when you have multiple SCXI chassis -- you indicate a single chassis so the 1349 should be correct.

In describing your problem, you don't identify the DAQ device or the channel of the DAQ card you are using to interface the SCXI chassis and to acquire the signal of the hydraulic controller.  Keep in mind, when you connect the SCXI chassis to the DAQ card, channel 0 is typically dedicated to reading the SCXI modules. This is described in the SCXI Getting Started manual, pg 1-17, 1-18.  If the hydraulic controller is connected to chn0, the value won't be read.

I would first verify the channel you've connected for the hydraulic controller.  If it is channel 0, connect to a different channel.  Use MAX to configure the channel and verify the signal.  If you still have conflicts, remove the 1520 from the chassis and check for the signal from the hydraulic controller on the appropriate channel. 

If you still have problems, identify the chn you are connecting for the hydraulic controller,  what you tried, and post your results.  Please include the model of DAQ card.

[OKors]

6281 PCI DAQ Card

[Russ@Davis]

Sorry, the way you listed, I missed the PCI-6281.

What were the results from my suggestions?

[Speedy_Badger]

Hello OKors,

While Russ@Davis is correct in stating that the SCXI-1346 is intended for chaining multiple SCXI chassis together, it is also the correct solution for your situation. As the knowledgebase article describes, the combination of the SCXI-1520 and SCXI-1349 will use a channel on your DAQ device for each of the 8 analog input channels of the 1520 (parallel operation). Since the SCXI-1346 is designed to internally disconnect unused channels and make use of a single channel (channel 0) it is a workaround that allows the SCXI-1180 to access these unused channels.

From a certain viewpoint, you could consider the SCXI-1180 as your "second" chassis in the system. The SCXI-1346 assigns the output channels of the SCXI-1520 to a single channel on your PCI-6281 and then frees up the unused channels for your external signals through the SCXI-1180.

I hope this clears up and confirms what you had already researched using the knowledgebase article.

Regards,