How to connect 80 inputs from PCI-6225 to SCB-68?

[Aaron T.]

Hello,

Recently, I purchased and received:

(1) PCI-6225 M Series DAQ card

(2) SHC68-68-EPM Cables

(2) SCB-68 Shielded Connector Blocks

This hardware is for a project that will require all 40 differential inputs to be wired to the connector blocks. 

First, I am unable to find an I/O label for using the SCB-68 with the 6225 card.  The closest I came to finding the required information was this post:

http://forums.ni.com/ni/board/message?board.id=250&message.id=18467&requireLogin=False&bcsi_scan_489...

However, the original poster's question was not answered.  The last post in this thread looked promising until I followed the link and found that none of the reference lable pdf files was for a 6225 card.  With further searching I was able to find a reference label for M series devices, but it only shows pin assignments for 16 total differential inputs (8 on connector 0 and 8 on connector 1).  Where can I find the pin assignments that show all 40 differential inputs???  Does one even exist?

Second, I have found some discussions about what cables are required to connect the 6225 to two SCB-68s.  It seems some information suggests two different cable types are required.  The product page for the 6225 only indicates that two cables are connected and then lists all the cable options.  Will two SHC68-68-EPM cables, as I have ordered, be sufficient for connecting to the connector blocks?

[Tom_W_[DE]]

Hi Aaron-

The documents are indeed attached to that KB, but a formatting problem masked a few of the links off.  I have attached the connector 1 pinout for the 6225 here.

The SHC68-68-EPM cable will work for connector 0.  However, the SHC68-68 cable is recommended for connector 1.

Hopefully this helps-

[Aaron T.]

Tom,

Thank you for the attached .pdf file.  It contains the exact information I was seeking.  Can you send a note to the web developers to fix the formatting so that all links are visible on the KB page?  That would save someone from searching the NI web site for an hour like I did trying to find terminal assignments for the 6225 card.

With regard to the cable, let's see if I understand this correctly... SHC68-68-EPM contains seperate analog and digital sections while the SHC-68-68 does not have separation for analog and digital signals.  The SHC68-68-EPM should be used with connector 0 on the PCI-6225 because this connector contains both analog and digital I/O.  The SHC-68-68 should be used with connector 1 on the PCI-6225 because it contains only analog inputs.

Currently, I have two SHC68-68-EPM cables.  I realize that I could use this cable with connector 1, there is a wire for each pin, but the shielding and twisted pair wires will not be optimal for analog signals. 

How would I know from looking at the product information page for the PCI-6225 that I need one of each cable?  The page says that two cables are required and says that the SHC68-68-EPM is the "NI Recommended" cable. 

Thanks again,

- Aaron

[Tom_W_[DE]]

Hi Aaron-

Absolutely- I forwarded a request to the web team as soon as I saw your post.

I'll also file a request with the web team to add a mention of the need for two different types of cables- our sales team should know the difference, but it's not obvious to someone who just orders from the web.  Thanks a lot for the valuable feedback.