Jump to content

As of July 17, 2015, the LabJack forums here at forums.labjack.com are shut down. New registrations, topics, and replies are disabled. All forums are in a read-only state for archive purposes.

Please visit our current forums at labjack.com/forums to view and make new posts. To post on the current forums, use your labjack.com login account. Your old LabJack forums login credentials have been retired. There are no longer separate logins for labjack.com and LabJack forums.


Sensor wiring / Calibrating

  • Please log in to reply
1 reply to this topic

#1 evendol

  • Members
  • 9 posts

Posted 02 October 2012 - 12:40 PM


Iíve posted before about reading out a Balluff sensor with the U6
This is the sensor: http://www.balluff.c...E_EN_145577.pdf

This sensor has a stroke of about 800 mm. When I restart my machine
I get an error of 0,3mm (= +/- 0,008 Volt).
When I recalibrate it reaches around 0,05mm repeatability, which I think is very good!

Now I am building a 3rd machine I have following questions:

1. What is the optimum cable to use for this?
I now use 12 x0,75 mm2 but plan to use 12x 0,5 mm2 shielded cable?

2. What kind of current can be expected in this measurement?
I can imagine that the measuring difference of 0,3mm can be caused by
change of wire resistance with changing temperature.



#2 LabJack Support

LabJack Support
  • Admin
  • 8677 posts

Posted 03 October 2012 - 07:39 AM

1. I would not expect the cable to make much difference. I suggest you do a test with a very short heavy duty cable, and see if the readings are any different than what you see with a long thin cable.

2. I assume you connect a power supply to pins 6 & 7, then connect pin 2 to GND on the U6 and pin 3 or 5 to AINx on the U6. Then you should only have the analog input bias current flowing on in/out of the GND and AINx terminals, which is on the order of 20nA:


If you have some sort of ground loop issue, you could have more current flowing in/out of the GND terminal, and perhaps that could cause a problem. Use the test in #1 above to see if this is even a problem.

The CB37 datasheet discusses this:


0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users