KUKA KRC4 with ethercat bus

  • Hello,


    First of all, i am new to KUKA robots and the tobot forum. So Hello!


    I have KUKA KRC4 with Beckoff ethercat bus. What i need to do is to control a relay which requires 24v with more current than what is available on the Beckoff El20809. There is also a EL9100 which i am not able to control from a KRL program. I am not even sure if is meant to supply voltage.


    I am on the lookout for transistor based (FET, MOSFET) solution.


    Any suggestions will be highly appreciated.


    Thanks!

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  • 1. welcome


    2. there are output cards rated for 2A per point but even EL2809 has outputs capable of driving loads drawing up to 0.5A. That is plenty for any relay or contactor i can think of being interfaced to a robot... Sooo... How much current your relay coil actually draws? show us the datasheet...


    3. you don't want to use mosfets etc. trust me. but if you really insist, i'll help


    4. EL9100 is not an output card, it is simple power terminal

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • Hej!


    Thank you for your reply.


    Now i feel that i must explain the situation more.


    The load is a Werma light.
    https://www.werma.com/en/s_c10…EM_24VDC_MC/81678055.html


    I need to control the color of the light by providing different 24v to different wires. The link will take
    You to the product page where you should be able to find the documentation. At the moment I have brown to +24V and blue to ground and the power is from a wall socket. This gives me red light. I want to connect and control the white wire from the controller and therefore connected it to the beckoff output module. This does not work very well. it gives me a strange color and sometimes it does work at all.


    The relay i have is from Euchner. ESM-BA-301. The relay is probably not meant for this, but this is what i have right now. It does not work well with the io module either when i connect it to a1 and a2. I had wired for as emergency switch example-
    https://www.euchner.de/en-us/P…afety-relay-ESM/ESM-BA301


    So this is the reason why i wanted to have a transistor solution. Can you please explain why such a solution will be bad? I am curious to know your answer.


    Please note that we are looking for solutions to implement in a lab and not in production.


    Thanks and best regards

  • hmmm..... you are having problems wiring a lamp.


    why do you think that designing and making circuit with transistors, including bias, conditioning gate/base etc for three channels is going to make this any simpler?


    besides, when doing industrial automation, please stick with something next guy can work with, try to avoid custom solutions.


    finally standard solution is by far the simplest and easiest - just read the data sheet and wire the lamp correctly then turn on outputs by program.


    if it is hard to recall binary codes 0-7, enumerate them (see example)

  • Hello again,


    Thank you for answer.


    I was trying the "more" complicated method after realizing that the beckoff modules were not able to power the lamps. The issue was not the code but the wiring itself. But we seem to have solved this issue.


  • I was trying the "more" complicated method after realizing that the beckoff modules were not able to power the lamps.


    Interesting, but - what led you to believe that 0.5A output is not enough to drive LED indicator lamp?


    LEDs are inherently low power. incandescent bulbs draw more current - specially when cold (high inrush current).
    But even largest incandescent indicators (say those in 855T from AB) are only 10W.
    standard output can drive 24V * 0.5A = 12W.

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • The documentation specifies that to achieve color control, you need 3-state "outputs": GND, +24V, and NC. Most I/O devices are only capable of providing the first two. What you most likely need is to add a relay circuit (going to raw transistors is pointless and self-defeating in this context) for each control line, in order to provide each line with all 3 states.
    The Werna light is most likely "cheating" by multiplexing opposite-polarity relays on the same wire, which is why you would need to ensure 3-state control of each wire in order to reliably obtain the full 7 colors the lamp is capable of. For a quick&dirty circuit, putting a SPST "enable" relay in series with a DPDT "24V or GND" relay, for each line, is probably the fastest quick&dirty solution. It will require 6 relays total, however (since Pin 3 is permanently tied to GND and should not be put on a relay).

  • i agree, that datasheet is not good - should not mentioned "NC".
    however, i seriously doubt that isolation is needed, just wire it to three outputs and be done with it.

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • Without an internal schematic, it's hard to be sure, but for other similar products I've encountered, achieving the full color spectrum required being able to block current on individual control lines, or to controllably pass it in either direction. If this light is similar, then grounding or powering a line when the color chart calls for "NC" may cause more LEDs to illuminate than desired.

  • I have only skimmed the requirements here, but would a tri-state push pull output like the Beckhoff EL2202 work? The outputs can be +24,0, or high impedance.


    I've used a similar card (can be configured as EL2502) to drive PWM outputs to RGB+W LEDs. I haven't used it configured as the e 2202, but even as a PWM output, it does push pull (which is nice because my LEDs are 24v common) not sure how you'd map the 2202 in WoV. I left my laptop at home, or I'd try it out.


    Neither of these cards are supported by KUKA, and I did have a version of WoV kill the EL2502 compatability, but I've had luck in the current version (again, no laptop, so can't check what that version is)

    Edited once, last by BrianR ().


  • I have only skimmed the requirements here, but would a tri-state push pull output like the Beckhoff EL2202 work? The outputs can be +24,0, or high impedance.


    I've used a similar card (can be configured as EL2502) to drive PWM outputs to RGB+W LEDs. I haven't used it configured as the e 2202, but even as a PWM output, it does push pull (which is nice because my LEDs are 24v common) not sure how you'd map the 2202 in WoV. I left my laptop at home, or I'd try it out.


    Neither of these cards are supported by KUKA, and I did have a version of WoV kill the EL2502 compatability, but I've had luck in the current version (again, no laptop, so can't check what that version is)


    Prrrrrrobably? The high-impedance state should be equivalent to "NC". The output cards shouldn't need to be supported by KUKA -- as long as the bus coupler is supported (and it is), you should have no issues adding any I/O device to that bus coupler as long as you have a valid definer file for it. Although I do wonder about the I/O mapping -- you'd need two bits per output on this card, to control the three states per output.


    Still, Panic mode has a point -- you should try a quick test of each control line on the lamp individually, and see how they turn out. If each line controls R, G, and B respectively, then he's right, and the "NC" shouldn't be technically necessary, because 3 "bits" of color will give you 7 combinations (R,G,B, RG,RB,GB,RGB). The high-impedance trick should only be necessary if the mfgr is pulling some strange multiplexing tricks with their LEDs internally.

  • Prrrrrrobably? The high-impedance state should be equivalent to "NC". The output cards shouldn't need to be supported by KUKA -- as long as the bus coupler is supported (and it is), you should have no issues adding any I/O device to that bus coupler as long as you have a valid definer file for it. Although I do wonder about the I/O mapping -- you'd need two bits per output on this card, to control the three states per output.


    Still, Panic mode has a point -- you should try a quick test of each control line on the lamp individually, and see how they turn out. If each line controls R, G, and B respectively, then he's right, and the "NC" shouldn't be technically necessary, because 3 "bits" of color will give you 7 combinations (R,G,B, RG,RB,GB,RGB). The high-impedance trick should only be necessary if the mfgr is pulling some strange multiplexing tricks with their LEDs internally.


    I've had EL2502 off of a EK1100 totally F things up on different versions of WoV. At least the only thing I could narrow down is separate laptops with newer versions than mine had problems with it (the 16bit PWM outputs getting mapped to different outputs, like the EL2502 were not consuming the data... or something...) Asked KUKA for the install of an older version of WoV, and then it was all fine on all laptops. It COULD be something else, but that was the common problem that I could pin down. I dug through how the 2 versions of WoV were creating the X44 config for the same project, and it WAS slightly different. This doesn't seem to be an issue in the current versions, but it did kind of scare me.

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