K8061 problems with emi

Kits PC Related Projects
1

hi velleman;
i have problems with the k8061 as follows:-

  1. in my system the cards are to work with a no. of 12V & 24V plungers.
    sometimes(3 out of 10) unexpected signals(usually from the digital
    outputs) evolve when the plungers are working. if i cut the power
    to the plungers the system is working fine. i read from the posts
    records that alexart might have the same problem(he posted it
    in sep-08-13). what can i do to solve this?
  2. what is the difference between k8061 & vm140?
    thank you for your attention.
    regards. from kit
2

To reduce the problems you may do following:

  • Use as short cables connected to the inputs and outputs of the K8061 as possible.
  • Use shielded cables. Shields can be connected to the K8061 GND terminals.
  • Add some capacitors 10nF … 100nF between input and output terminals and GND.
  • Put the K8061 in a metal box.

[quote]2) what is the difference between k8061 & vm140?[/quote]There is no difference except that the VM140 is a factory built version of the K8061.

3

thank you for your swift response:-

  1. i’ll tell you the result in a couple of weeks; but the cables provided
    for the i/o terminals are not shielded. should i shield the 20cm cables?
    2)do you mean that if i order the k8061 i have to solder all the parts
    onto the pcb and test it before it can be used?
4

[quote]1) i’ll tell you the result in a couple of weeks; but the cables provided
for the i/o terminals are not shielded. should i shield the 20cm cables? [/quote]Difficult to say if there is any help or not…
You may first try adding 100nF capacitors between the used input/output terminals and GND.

[quote]2)do you mean that if i order the k8061 i have to solder all the parts
onto the pcb and test it before it can be used[/quote]Yes.

5

in these weeks i connected all the used outputs(both analogue and digital) with 100nf caps and used
shielded cables. the results are as follows:-

  1. unexpected signals greatly diminished(success rate about 95%);
  2. all error(unexpected) signals are from the analogue outputs; digital outputs’ failure rate 0%;
  3. found it impossible to use shielded cable for the whole length;
    doubts:-
  4. could it be better if the 100nf caps are pre-installed onto the k8061? many people might have the
    same problem;
  5. any other way/s suggestion/s to further increase the success rate(95% is never good enough)?
6

[quote]1) could it be better if the 100nf caps are pre-installed onto the k8061? many people might have the
same problem;[/quote]Yes, this could have been a reasonable option.

[quote]2) any other way/s suggestion/s to further increase the success rate(95% is never good enough)?[/quote]The next step may be to put the whole K8061 board in a metal box.
Connect the box to the GND of the board.
Connect all the cable shields to the metal box.
You may also use feedthrough capacitors and put all the wires to go through these capacitors.