DMM4070 trigger connector

[mperu]

Hi all,

I wonder which kind of connector (brand/type) I should use to connect an external trigger signal to a PCI DMM 4070.

Thank you for helping.

Michel

[R_Duval]

Hello Michel.

You should phone to the NI Commercial Service.

They will advice you on this choice.

Regards.

[mperu]

Hi,

I called the french hotline and the the answer that I got is "minidin", far from enough to buy a connector... What I search for is a brand name and a reference of the connector.

This is the kind of crazy situation where you loose time searching for something which should be written somewhere in the documentation. Presently I am searching the paper catalogs of electronics vendors to find something which could work.

Anyway I thank you for the suggestion.

Michel

[wildcat_600]

Here is a link to the trigger cable NI sells to go into the AUX connector.  Is this what you're looking for?

Brian P.

[mperu]

Hi,

I want to build a custom cable that I will use here at my institute, consequently I need to know the brand and the type of the connector to be plugged into the DMM4070 trigger connector.

Thank you for helping,

Michel

[wildcat_600]

The cables we use at NI are custom made, but they are 9-pin mini din connectors.  There are different types of 9 pin din connectors on the market, but I did a few searches and found some that are similar.  Here is one cable that I found that has not been tested by NI but it looks like it has the same pin configuration that we use on our DMMs.  I don't know how easy it will be to find just a connector of this type but another option would be to get a trigger cable from NI and just cut it so you can make your custom connections.  I hope this helps.

Brian P.

[mperu]

Hi,

Thank you for all of your help.

I still continue to search for the connector, I can't imagine buying a NI cable just to cut it in order to make a custom cable.

Have a nice time this weekend.

Michel

[RayFarmer]

Hi,

I just did a google search for "9-pin mini din connectors" and came up with a number of hits for suppliers of such an item.

Regards

Ray Farmer

[mperu]

Hi,

I spent some time to finally find: Radiospares - Mini-DIN 9 pins male - Ref: 176-8785 - Cost: 1.5 euros

I am waiting for the part and I will check on monday that this is the right connector I am waiting for.

NI should consider that some people need to build custom cables and that it could well be a good idea to give the reference of the connectors one can connect to a NI product.

Thank you to all of you who kept me motivated to continue my quest of the Graal.

Have a nice weekend.

Michel Peru

[Claudia]

Michel,

NI sells two cables for the AUX connector:

1) AUX Trigger Cable (NI Part Number 184931-0R5 (0.5m long)). Brian pointed this one to you earlier.
2) SH9MD-AUX Cable (NI Part Number 185258-01 (1m long) and 185258-02 (2m long))

The description of these cables and their pinout is in the NI Digital Multimeters Help File. This Help file can be accessed thorugh the web (see link below) and also gets installed in your computer when you install the driver (for Windows machines go to Start >> Programs>>National Instruments>>NI DMM>> Documentation).

For your convenience, I am also attaching an image to this Discussion Forum that has the same images you can find in the Help File.

The Help file lists what pins you can use for triggering. Pin 2 of the AUX connector is the GROUND. Pin 6 is the Measurement Complete signal (the DMM outputs this signal when a measurement is completed), and both pin 9 (names Ext Trigger) and pin 3 (named AUX Trigger) are input triggers to the DMM.
The rest of the pins are reserved for control of SCXI chassis; so leave those unconnected and keep them unused.

IMPORTANT: The voltage at the AUX connector pins is reference to the ground of the computer and not to the ground of the circuit being measured through the bananas (the bananas connect to the DMMs isolated measurement circuitry).
The specifications of all NI DMMs reads: "Caution: The AUX I/O connector on the NI 4070/4072 and the interdevice connector on the NI PCI-4070 are not isolated. These connectors are not referenced to your measurement circuit, but they are referenced to the ground of your PXI chassis or computer. The digital signals on these connectors should not operate beyond –0.5 to 5.5 V of your chassis or computer ground."

Assuming you could use the SH9MD-AUX 2 meter long cable, you could install the connector at the other end of your application. The female-type connector used in the boards is a Mini Din connector, like the one shown in page 10 of the following link: http://www.methode.com/catalog/catalog/sec05_06.pdf

We careful tryign to make the cable too long. Any cable has its own resistance, capacitance and inductance per unit length. Even if you consider the inductance negligible, the resistance and lumped capacitance will act as a low-pass filter to your signal degrading the signal integrity of your digital signals. The DMM is pretty robust detecting input triggers, but I would recommend you to try maintain the length of the cable to 2 meters maximum (and then you could just use the SH9MD-AUX Cable).

Hope this helps,

- Claudia L