Cellular Router Fails to Find Specified Access Point When Connecting to PLC: Causes and Solutions
With the rapid development of Industrial Internet of Things (IIoT) technology, more and more traditional industries are adopting Programmable Logic Controllers (PLCs) and Cellular Router to achieve remote monitoring, control, and management of their equipment. However, in practical applications, the Cellular Router may encounter an issue of "failed to find the specified access point" when attempting to connect to a PLC. This article, from the perspective of a senior engineer, will analyze the potential causes of this problem and provide corresponding solutions.
I. Problem Analysis
When an Cellular Router tries to connect to a PLC but encounters the message "failed to find the specified access point," it typically indicates that the router is unable to properly recognize or access the PLC's network interface. This issue can be caused by a variety of factors, including but not limited to the following:
1. Incorrect network configuration: The network configurations of the Cellular Router and PLC may not match, such as incorrect IP addresses, subnet masks, gateways, etc., preventing them from communicating on the same network.
2. Hardware failure: There may be issues with the Cellular Router or PLC's hardware, such as damaged network interface cards or poor Ethernet cable connections, leading to disrupted communication.
3. Software setting issues: The PLC's communication protocol, port number, baud rate, and other settings may be incompatible or misconfigured with the Cellular Router, preventing a connection from being established.
4. Firewall or security settings: Firewalls or security devices within the network may be blocking communication between the Cellular Router and PLC, causing the connection to fail.
II. Solutions
To address the "failed to find the specified access point" issue, we can take the following measures:
1. Check network configuration:
● Ensure that the IP addresses, subnet masks, gateways, and other network parameters of the Cellular Router and PLC are set correctly and within the same network segment.
● Verify that the DNS settings are correct for proper domain name resolution.
● Check if the DHCP (Dynamic Host Configuration Protocol) function of the Cellular Router is enabled and that the PLC can obtain an IP address correctly.
2. Check hardware connections:
● Examine the network interface cards of the Cellular Router and PLC for damage and ensure that the Ethernet cables are securely connected without damage or looseness.
● Try replacing the Ethernet cables or network interface cards to rule out hardware failure.
3. Check software settings:
● Confirm that the PLC's communication protocol, port number, baud rate, and other settings are compatible with the Cellular Router and make necessary adjustments.
● Verify if the VPN (Virtual Private Network) function of the Cellular Router is configured correctly to enable remote access.
● Check the PLC's firewall or security settings to ensure that they are not blocking access requests from the Cellular Router.
4. Restart devices and the network:
● Try restarting the Cellular Router, PLC, and related network devices to address issues caused by prolonged operation.
● Examine the network device's log records to obtain more detailed information about the connection issue.
5. Update software and drivers:
● Ensure that the software versions of the Cellular Router and PLC are up-to-date for better compatibility and stability.
● Update the network devices' drivers and firmware to ensure smooth communication with the Cellular Router and PLC.
6. Contact technical support:
If none of the above methods resolve the issue, it is recommended to contact the technical support teams of the Cellular Router and PLC manufacturers for professional assistance and guidance.
In conclusion, "failed to find the specified access point" is a common issue when an Cellular Router attempts to connect to a PLC. By carefully checking network configuration, hardware connections, software settings, and restarting devices and the network, we can effectively resolve this issue and ensure smooth communication between the Cellular Router and PLC. Meanwhile, we should remain vigilant and keep up with new technologies and methods to adapt to the constantly changing industrial IoT environment.
