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Click Sinking Analog Output to GS2 Sinking Analog Input.....How does that happen?

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  • Click Sinking Analog Output to GS2 Sinking Analog Input.....How does that happen?

    I'm trying to control a GS2 via analog speed reference. I'm scaling 0-60Hz to 4-20mA out of the Click Koyo to the analog input of the GS2. When I put a meter in series to check the amperage to see if it matches what the output status states is current mA level, I get nothing. When I put it on the 10VDC output of the drive (internally supplied) which is the terminal adjacent to the Analog Input on the drive, there's my current reference. So I believe I have a sinking output to a sinking input. How do I make this work? Any suggestions are greatly appreciated.


  • #2
    You will need a signal conditioner such as a FC-33. http://www.automationdirect.com/pn/FC-33
    If you have an urgent issue, please contact AutomationDirect's Technical Support team.

    AutomationDirect.com Technical Support: 1(800) 633-0405 or (770) 844-4200 Email Tech Support

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    • #3
      One might alternatively consider adding a https://www.automationdirect.com/adc...-z-o/c0-04da-1 which not only has the more conventional sourcing output, it would also give you an additional three outputs in case you ever needed them.

      On the other hand, an isolating conditioner would give you isolation, so if you only need one channel that might be the best option, but for more than one channel conditioners could get expensive.

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      • #4
        Analog output is not defined in terms of sourcing or sinking. Only digital IO are defined in terms of sourcing and sinking.
        Analog output is essentially a power supply able to provide the current. Two conductors leave the plc output: signal and com.

        to connect the analog output to drive analog input:
        1. Connect the drive analog com(AC) to the plc com port corresponding to the analog output
        2. Connect the plc output to drive analog input(AI)
        3. Make sure the drive is configured to accept analog reference (P4.00 set to 03)

        This is off-topic, but I hope will be found useful:
        About dc sinking or sourcing outputs
        sourcing means that the load is already connected to negative rail of a dc circuit and the plc output provides a path from positive rail to the load. It is implemented using a bipolar pnp transistor as a switch.
        Sinking means that the load is already connected to positive rail and the connection to the plc output provides a path to the negative rail. Is implemented using a bipolar npn transistor.

        the load is a dc device like a dc relay.

        about dc sinking or sourcing inputs
        in this case, the load is represented by plc input.
        the input is called sinking if the path provided by the device connected to the input is towards the negative rail.
        It is called sourcing if it requires a path from positive dc rail.

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        • #5
          Originally posted by Alexandru View Post
          Analog output is not defined in terms of sourcing or sinking. Only digital IO are defined in terms of sourcing and sinking.
          Analog output is essentially a power supply able to provide the current. Two conductors leave the plc output: signal and com.
          The CLICK built in current outputs are weird, they are not power supplies, the are current sinks, and both outputs share a common so it is not clear how to put one in series with an external power supply, though now that I'm writing this, I'm wondering, if one was only using one analog output, could one connect the common to the load and the "output" to a suitable power supply?

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          • #6
            to connect the analog output to drive analog input:
            1. Connect the drive analog com(AC) to the plc com port corresponding to the analog output
            2. Connect the plc output to drive analog input(AI)
            3. Make sure the drive is configured to accept analog reference (P4.00 set to 03)
            This is how it is connected. There is no current reference with this configuration.

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            • #7
              I am using only one analog output from the PLC. That is really all I need so I'm thinking isolation is probably best. I've never used a signal conditioner before or implemented one into an application. Is the one that is linked above gonna work with this application or should I just call in and have them spec it out? My coworker (controls engineer) also suggested perhaps buying the add on output module that would provide 4-20mA sourcing. Is this a better idea? Is there a way to use the 10VDC signal (internal power supply) out of the GS2 to accomplish this? I can see the current speed reference on the multimeter in the 20/200 mA range by interrupting the circuit and referencing the analog output of the PLC and the 10VDC signal out of the GS2.

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              • #8
                Either the FC-33 or the C0-04DA-1 are the correct solutions that ADC tech support would recommend. Trying to use the GS2 internal supply to "fix" the issue is going to likely result in a dead drive.
                If you have an urgent issue, please contact AutomationDirect's Technical Support team.

                AutomationDirect.com Technical Support: 1(800) 633-0405 or (770) 844-4200 Email Tech Support

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                • #9
                  Good to know. I'll get the FC-33 ordered. Thank you!

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                  • #10
                    You donít need a signal conditioner or isolator. The purpose of such a device is to allow for example more receivers to be connected to the same analog signal supply. Therefore, the analog signal needs split and each circuit may need isolation to prevent interference. Not your case.

                    What you need is to understand the nature of the fault. You have a fault in your doing. Whether is your fault or a fault in hardware, is not clear now.

                    Letís clear the hardware
                    1. Plc side
                    1.1. Connect a 3k resistor to analog out port. Connect an ammeter between the other end of the resistor and the analog com port.
                    ( you could also use a voltmeter connected parallel with resistor, while resistor is connected between analog port and analog com)
                    1.2. Program the plc to output different analog values. Check the ammeter readings. If everything is fine, then the plc is clear.
                    2. Drive side
                    2.1. Configure the drive to accept speed reference from external potentiometer.
                    2.2. Connect a 3k potentiometer between AI+, AI and AC
                    2.3. Check on drive display the frequency change over frequency range. If everything is fine, the drive is clear.

                    I will risk an opinion, saying that you wonít clear the hardware. Main reason being an inconsistent configuration of the drive. Please reset the drive, reconfigure as required and if still doesnít work, I would call support. It is possible that another drive parameter is not configured to allow motion with external analog reference.

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                    • #11
                      Originally posted by Alexandru View Post
                      You donít need a signal conditioner or isolator. The purpose of such a device is to allow for example more receivers to be connected to the same analog signal supply. Therefore, the analog signal needs split and each circuit may need isolation to prevent interference. Not your case.

                      What you need is to understand the nature of the fault. You have a fault in your doing. Whether is your fault or a fault in hardware, is not clear now.


                      1.1. Connect a 3k resistor to analog out port. Connect an ammeter between the other end of the resistor and the analog com port.
                      ( you could also use a voltmeter connected parallel with resistor, while resistor is connected between analog port and analog com)
                      1.2. Program the plc to output different analog values. Check the ammeter readings. If everything is fine, then the plc is clear.
                      As I wrote before, the CLICK built in (on the brick) analog current outputs are weird, your procedure WILL show that the PLC is at "fault" (but it is really more "weird" that "faulty") Also 24V / 3K ohms is only 8mA so one wouldn't get correct readings via your procedure even with a conventional sourcing output.

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                      • #12
                        There is nothing wrong with the plc analog outputs. The drive should work on direct connection to plc. If it doesnít work, is either due to wrong programming, wrong connection or a hardware fault which is not signalled. My guess is that there is nothing wrong with the hardware.

                        The 3k resistance value is mentioned in the drive manual. Wether a smaller resistance would be more appropriate or not, is the responsibility of the one doing the troubleshooting. I believe that for troubleshooting purposes, 3k is alright. It will produce enough correct readings to get the motion going and the signal checked..

                        I think no one shoyld should get smart with weird assumptions about the functioning of plc outputs. Such allegations are unfair to start with, and turn the attention from troubleshooting an issue which could as well be a simple programming misunderstanding or configuring a drive. If the issue is a hardware glitch, it would be appropriate to hear about it in detail and not in unsubstantiated gossip.

                        Lets be honest in our opinions and refrain from spreading misleading rumours.

                        Comment



                        • #13
                          I apologize I didnít notice earlier.
                          The way you check the plc output is not correct.
                          By connecting an ammeter between analog out and analog com, you have created a short-circuit.
                          The ammeter can be interfaced series between the load negative connection and the analog com. It also works between analog out and load positive.
                          What you need to do in order to check the plc analog port is to use a load resistor. Please visit my post on ď clearing the hardwareĒ

                          you canít have a current reading on a 0-10vdc output of the drive, because the drive outputs voltage. More concerning is that you state you have a current reading, meaning that you have shortened the analog voltage out of the drive.

                          The check that you have done both on plc output and drive output could have damaged both devices because you used the low resistance of the ammeter to effectively short-circuit each output. Remember to use the load resistance next time.

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                          • #14
                            ON the GS2 the "Load negative connection" is a common connection shared with the analog output, while if one was not suing the analog output, it might be possible to use it as the current input connected to the CLICKs weird sinking output, it certainly would not be the proper procedure, and I would not recommend trying it for risk of damaging the drive.

                            As I've written a few time already, the CLICK's built in (on the brick) analog current output are WIERD.

                            Also 4-20mA current outputs are by definition current limited, they (should) be able to drive a short circuit just fine, in fact too high of loop resistance can be a problem.
                            On the other hand a current input is probably not current limited since it expects a controlled current from the source, so connecting a power supply directly to current input might be bad, though it might have enough resistance to avoid destruction. By power supply I mean high current 24V, the I suspect the GS2's 10V is current limited (rated 10mA max load) so I wouldn't be too worried about it.

                            But, the original poster's connection would not have worked in any case (because the CLICK is weird) so we shouldn't assume he damaged something just because it doesn't work.

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                            • #15
                              lets hear it from the initiator.
                              I have sent a clear procedure to check the hardware.
                              the only thing im really concerned is that there could be a conflicting config for analog speed reference, which prevents motion and yet it doesn't post an error on the drive. is a long call though, but worth making if hardware testing (as recommended) fails.
                              to clear this as well, I would call support just to make sure that the drive config is ok. best do it after the hardware is all set.
                              I would actually start the troubleshooting with a drive reset.

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