IF CAN Module issues

sean · October 20, 2020, 2:15am

Hello, I am using an AXC F 2152, that I’ve attached a IF CAN module to. I’ve downloaded the CANbus library from the PLCnext store and I’ve download the Example “CAN_9_EXA_AXL_CO” project to the PLC. For some reason, the PLC seems to be unable to connect properly to the Axioline modules. I’m not sure whether it’s a programming issue or a physical issue, but the only changes I’ve made to the project are: changing the Ip address to match the PLC, changed the “iExample” to 7000 (for the IL_CO_SDO_RD) and changing the NodeID to match the Can reciever device. Are there any setup processes I have missed when starting the project? Kind regards, Sean

Martin_PLCnext_Techn · October 20, 2020, 5:24am

Hi Sean, It looks like you don’t have +24 VDC and 0 VDC wired to the CANbus module, so this should be done at some stage. Please also check that you have included the correct CAN module in the PLCnext Engineer Axioline bus configuration. I haven’t looked at the example project, but your reference to “IL_CO_SDO_RD” makes it sound like you’re using a project that uses the Inline version of the CAN bus module, not the Axioline version. Please make sure you are using a project that includes the correct version of the CANbus module - you should see this in the left-hand “Project” frame of PLCnext Engineer. If you see “Inline” in the project tree instead of Axioline", then this is not correct. Hope this helps. ~ Martin.

sean · October 21, 2020, 12:45am

G’day Martin, I hadn’t wired in a +24 VDC and 0 VDC power supply into the CAN module as I had thought the back connector would supply power from the PLC. Nevertheless I have wired in the power supply, but the results have not changed. This is a screenshot of the Example project from the CANbus library and it has the use of a AXL F IF CAN 1H. I believe it is the correct module. It aso shows that the project uses the AXL_CAN_COMM function block, but the data is later converted to IL messages using the CAN_TO_IL_STRUCT fb. Is this correct? Kind regards, Sean

Martin_PLCnext_Techn · October 21, 2020, 6:41am

Hi Sean, Yes, the hardware configuration (at least) looks correct. You should be able to start the PLC without any Axioline bus errors, which is the problem shown in the video. We have had problems reported in the past where the DIN rail connector pins are either damaged or not connected together securely, so it is worth checking this: Can you please dis-assemble and then re-assemble the complete station?

                                             * Remove the PLC and I/O module from the DIN rail.
                                             * Remove the DIN-rail connectors and pull them apart.
                                             * Make sure that there are no damaged pins on the DIN-rail connectors - incuding the pins between each pair of DIN rail connectors.
                                             * Clip each of the connectors back on to the DIN rail individually, and then slide them together so they are connected securely.
                                             * Re-seat the PLC and I/O module on the DIN-rail connectors.

Please also start with an empty project in PLCnext Engineer, with only the CANbus module added to the project template. With this simple project, the PLC should start up without any Axioline errors. If that doesn’t happen, then we will need to investigate further. Regards,
Martin.

sean · October 26, 2020, 2:05am

Hey Martin, I’ve done all the steps you’ve laid out, but unfortunately the IF CAN module is still showing errors. I have attempted to use a different DIN rail connector from a RS UNI module, that we can confirm that definitively functioned correctly. None of the pins are seemingly damaged and the code on the AXC F 2152 is just an empty project with the IF CAN module in the Axioline F. How would you recommend proceeding from here? The CAN function of my upcoming project is vital to the client. Kind regards, Sean

Martin_PLCnext_Techn · October 26, 2020, 10:03am

Hi Sean, My mistake, I thought the video showed an Axioline error, but on second look the D LED is solid green so that means the CANbus module is communicating OK with the PLC. So, any problems after that are probably due to either CANbus wiring, or the PLCnext Engineer program. Are you able to include a sketch of the CANbus wiring? I am told that the following are important:

                                             * Can High and Low
                                             * GND
                                             * Shield
                                             * 120Ω Terminating Resistor at either end of the bus

Can you also please include a screen shot showing the settings on the CANbus module “Parameters” page in PLCnext Engineer? ~ Martin.

sean · October 27, 2020, 2:21am

Hey Martin, In terms of wiring, I have been given this schematic by the supplier. I have connected CANL1 to Terminal Point 10 on the IF CAN, CANH1 to TP 00 and I’m unsure of whether the CAN REF above is either GND or SHLD but I have attempted both and neither seem to make a difference. In terms of Termination resistors, I have been told that there is a termination resistor within the receiver, but I have not connected a resistor to the IF CAN itself. Do I just connect a 120 ohm resistor between 02 and 03 on the module? This is the settings on the CANbus module “Parameters” page in PLCnext Engineer. Sean.

frankphoenixcontactd · October 27, 2020, 12:27pm

Hi Sean, I’m answering on behalf of Martin.

According to our CAN specialist indicates the 10 LED that the physical layer is not even detected and that most of those cases the termination is the cause. Please double check if the termination (120Ohm) is blugged in the terminals 02 & 03 (refer the datasheet). In case this does not relsove the problem we should arrange a direct contact, please come back to me → fwalde@phoenixcontact.com (ticket reference 202132). Take care, Frank

sean · October 28, 2020, 1:21am

Thank you Martin and Frank! It was the Termination Resistor that was the issue. Last question, must the resistor be precisely 120 ohms? Than you, Sean

Martin_PLCnext_Techn · October 28, 2020, 8:16am

Hi Sean, The permissible resistor value(s) should be mentioned in the CANbus specifications, or in other general CANbus publications. I guess that if you are installing or working with a CANbus network, the complete physical layer (not only the resistor value) should comply with the CANbus standards. Regards,

Martin.