02-22-2022 06:41 PM
The power connector on the back of my USB-DAQ shows the letters C and V.
is the C ground? And V positive?
I don’t recall ever seeing a DC power connector labeled that way.
02-22-2022 06:49 PM
02-22-2022 07:30 PM
I would also guess the same C - Common/Gnd and V - Voltage??
What exact DAQ is that? I don't think it is NI, good to refer to the manual than blow up with reverse polarity.
02-23-2022 06:30 AM - edited 02-23-2022 07:06 AM
It could be NI. It's they same type of connector you have on the cRIO, although there it is usually 4 pins for a redundant power supply connection. And it is labeled V1, C, V2, C on them too. As it is a keyed connector you should have no problems if you use the power supply that is delivered with the device. If you need to do your own cabling, basic electrotechnical knowledge is required and a look in the according manual will usually help.
This is for instance for the cRIO-9035. Take a look on page 8 for the explanation of the power connector. All NI devices have similar manuals which do describe such details pretty well. My only grasp with them is that they are usually very thin on more specific technical details about the device that are sometimes necessary to know to properly integrate a device in a bigger project. They are usually very careful to not specify too much, that may bite them if they have to change some internal component and such published but deemed unnecessary specs might suddenly change by that.
NI sells the according pluggable terminator block connectors usually too, in packs of 5 or 10, but if you have some other electronics distributor like Farnell, Mouser, RS Components or Digikey, you can buy them from them a lot cheaper. The manufacturer is either Phoenix Contacts, Molex, Weidmuller or Würth Electronics and sometimes some other ones. You need the 3.81 mm pitch variants. Weidmüller and Metz Connect are usually black like the NI ones, the others are green but work just as well.
02-23-2022 09:01 AM - edited 02-23-2022 09:21 AM
See the
_____
—–—
Symbol to the right of the "11 - 30 V"?
It indicates that internally the input is differential non-referenced.
C is Common. The 11 - 30 indicates the range of potential so V is Positive w respect to common ( a -30 - -11) would require a negative input)
C is Probably attached to
Chassis through a largish restance
____
\\\
And isolated from Earth Ground.
___
—
-
02-23-2022 09:08 AM
Use a meter and find out...
02-23-2022 09:13 AM
@RTSLVU wrote:
Use a meter and find out...
That just begs for users to remain uneducated about electrical symbols and is no substitute for RTFM! 😀
02-23-2022 09:39 AM
02-23-2022 09:45 AM
Better GTFM then. 😄
02-23-2022 04:14 PM
@santo_13 wrote:
I would also guess the same C - Common/Gnd and V - Voltage??
What exact DAQ is that? I don't think it is NI, good to refer to the manual than blow up with reverse polarity.
It's definitely a NI DAQ. See this manual:
https://www.ni.com/pdf/manuals/370784k.pdf
Look at page 20 (labeled 1-6 in the manual):
I have one on the desk next to me. No multimeter nearby though or I could actually check the pin output on the power supply.