Hello, I am currently experiencing difficulties in establishing communication with my CP1H PLC using the CP1W-C1F11 series option board, which utilizes USB to RS485. I have successfully tested communication across the USB RS485 converter by connecting two converter units and confirming communication using an SScom terminal emulator. I have carefully adjusted the dip switches on both the option board and the CPU (with switch number 4 in the off position) to ensure correct settings. The series port one (left-hand side) has been configured in CX One with the appropriate baud rates. While setting up the PLC in CX One and switching to sysmac and adjusting the driver settings, I have encountered an issue where com port 4 (used on my laptop) automatically appears, but I am unable to establish communication even in auto online mode. The amber light on the option board consistently illuminates every time the PLC switches between different protocol options. Additionally, I have observed that when launching AHMI, the amber light on the option board synchronizes with the transmission light on the USB to RS485 converter. I have already verified that the RS485 is using a two-wire system and have checked that the wires are correctly connected. I have some doubts about the functionality of the series option board and am seeking suggestions on how to test it. One method I am considering is sending a signal created in ladder logic back to the laptop and verifying it using the terminal emulator. Any alternative methods or advice to troubleshoot this issue would be greatly appreciated.
Upon reviewing the manual, it is specified that communication will be carried out via Host Link. This suggests that establishing a connection to CX Programmer should be feasible and is worth trying as the first step. Utilizing the terminal emulator, as you intend to do, seems like the right approach. When configuring the connection with CX Programmer, navigate to CIF11 settings in CX Programmer under PLC Settings > Serial Port (1 or 2). Adjust your laptop's com settings in the Change PLC dialog by selecting Network Type as SYSMAC WAY. It is crucial to ensure the serial parameters match and that the Host Link Unit Numbers align. Although they typically default to "0", it is essential to verify, especially when using RS485 where multiple Host Link devices are possible. For ladder programming, utilize the TXD(236) and RXD(235) instructions.
Hello IO-Rack, I appreciate your help in navigating through my current situation. Your assistance has certainly enhanced my comprehension of the system. From what I understand, switching cpu dipswitch four to the off position enables no-protocol type communications, utilizing TXD(236) and RXD(235). For the sysmac method and host link, the dip switch should be set to on/auto, directing data to the serial communications path on the series option board. I attempted to connect my laptop's comms port to the sscom v5.13.1 terminal emulator, which worked fine during loopback testing but not when connected to the PLC's single port. I introduced easy modbus logic to the PLC, alongside Qmodmaster, and although I could establish a connection with the PLC, I encountered issues identifying the slave and exchanging data. As a mechanical engineer exploring PLCs with basic skills, I am considering trying a different series option board, as the Chinese import I used may not be of good quality. It's worth noting that switching dipswitch four back to on caused the comms light on the option board to cease responding to incoming signals. It remained inactive in the on position.
From what I recall, Host Link operates on a full duplex protocol and is not compatible with RS485. In this case, utilizing RS422 is necessary. The CP1W-CIF11 offers support for both RS422 and RS485. RS485 is commonly chosen for Modbus Master and Compoway/F protocols. In our experience, we have consistently utilized HostLink with either RS232C or RS422 connections.
SVN explained that Host Link operates as a full duplex protocol and is not compatible with RS485. It seems that you are correct, and I apologize for the lack of information. If your adapter supports RS422, you may still be able to create a temporary wiring solution to confirm the connection with CX Programmer.
Thank you for your feedback. I used CP1h with easy Modbus master ladder logic connected to my laptop via USB to RS485. While we successfully received data from the PLC using Qmod master, we encountered difficulties in sending data back. This issue has led me to consider the compatibility of the RS422 interface, particularly with the CP1W-CIF11 option board. There is also the CP1W-CIF12 option board which may be more suitable for RS485 communication. It has been suggested that RS422 can transmit data to RS485 but cannot receive it in return. This has raised questions about the possibility of data loss when transmitting signals from RS485 to the PLC. The versatility of the CP1W-CIF11 in supporting two protocols without a dip switch mechanism is also a cause for confusion. I am now leaning towards acquiring the CIF12 option board, despite its higher cost. Additionally, there are concerns regarding the setup of the PLC in Modbus master mode and the Advanced HMI in slave mode, without any specified IP address. This confusion may be attributed to the use of Modbus RTU or a missing configuration setting.
From what you've shared about your testing setup, it seems like you've ensured all the necessary physical and software configurations are as they should be, which is really thorough groundwork. Regarding your communication issue with the CP1H PLC, one of the things I'd recommend as a possible solution would be to check the PC's Device Manager to ascertain whether the CP1W-CIF11 has been recognized correctly by the system. If it isn’t correctly recognized, you might need to download and reinstall the drivers. As for testing the option board's functionality, your idea of sending a ladder logic signal back to the laptop does sound like a viable option. Alternatively, you could try using a known functioning PLC to see if communication can be established. Substituting components in a system for ones known to be working is a great way to isolate faults. These steps could help identify where the problem is originating from and, consequently, lead you towards the solution.
It seems like you've done a thorough job trying to identify the issue, so well done on that. You mentioned testing communication through SScom terminal emulator with two converter units, but have you tried running a loopback test directly on the problematic CP1W-C1F11 option board? If the board responds correctly, it's likely in working order and the issue may lie elsewhere. If it doesn't respond or provides an incorrect response, the board itself could be faulty. Also, consider checking the termination resistor, as incorrect termination can sometimes cause communication problems for RS485 networks. There are elaborate ways to test, like using an oscilloscope, but starting with simple methods can potentially help identify the issue. Finally, please ensure to use the latest drivers for your USB to RS485 converter. Outdated drivers can often obstruct communication protocols.
Based on the description of your problem, it sounds like you've been pretty thorough with your troubleshooting. You mentioned that you have some doubts about the series option board's functionality. Have you considered trying a different board to rule out hardware failure? Also, your idea of sending a signal via ladder logic is a solid troubleshooting technique and could provide some valuable insights. However, I'd advise double-checking your wiring connections, as there might be a potential issue with them that's causing the miscommunication. Sometimes, the simplest solutions are often overlooked. Lastly, ensure that your RS485 to USB converter is compatible with CP1H PLC - incompatibility is a common cause for communication breakdown.
It sounds like you've done a thorough job of troubleshooting your setup, but the communication issue can definitely be tricky! One thing you might want to check is the grounding and termination of your RS485 lines, as improper grounding can often lead to communication problems. Also, since the amber light indicates activity, it could be useful to try swapping out the USB to RS485 converter just in case it’s not playing nicely with the PLC. Testing your ladder logic signal back to the laptop is a great idea, as it could help confirm if the PLC is actually processing and responding as expected. Keep us updated on your progress; I'm curious to see what resolves it for you!
✅ Work Order Management
✅ Asset Tracking
✅ Preventive Maintenance
✅ Inspection Report
We have received your information. We will share Schedule Demo details on your Mail Id.
Answer: Answer: To troubleshoot communication problems, ensure that the dip switches on both the option board and the CPU are correctly set, verify the baud rates in CX One, and confirm the RS485 wiring is correct. Consider testing communication by creating a signal in ladder logic and verifying it using a terminal emulator.
Answer: Answer: The amber light on the option board may indicate activity related to communication protocol changes. In this case, the light synchronizing with the transmission light on the USB to RS485 converter suggests communication attempts.
Answer: Answer: Ensure that the driver settings in CX One are correctly adjusted for the sysmac platform. If com port 4 is detected but communication fails, double-check the settings and consider troubleshooting steps such as verifying hardware connections and testing communication with a terminal emulator.
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.