Micro 820 PLC trainer - Issue disabling DHCP

[JleDeLuca]

The micro 820 is visible in RS Who when I configure my Ethernet to capture the random IP.

I am getting an error when following the steps below:

1. Set home ethernet adapter to Obtain an IP address automatically
2. Open the BOOTP DHCP EtherNet/IP commissioning tool
3. Select the MAC address associated with my Micro 820
4. Add a relation with a compatible IP address
5. Change the IP address on my home ethernet adapter to a compatible IP
6. Disable BOOTP/DHCP

Error --> “[set_attribute_single] (15)”

Alternative method, with a different error while trying to achieve the same goal in RSLinx.

Shutdown Connected Components Workbench and RSLinx Classic software.
Open Windows Ethernet card settings and set IP configuration to:
IP = 169.254.0.1
Subnet Mask = 255.255.0.0
Open the RSLinx Classic software.
Go to Communications –> Configure Drivers…
From Available Driver Types pull down list select EtherNet/IP Driver.
Add new driver by selecting OK.
Configure driver to browse your local subnet’s network card.
Click Apply to the settings and then hit OK.
Close the Configure Drivers window.
Go to Communications –> RSWho.
Expand the Ethernet/IP (AB_ETHIP-1) driver created before to allow the software to scan the subnet.
Right click on controller and select Module Configuration.
In Module Configuration, click on Port Configuration.
Set the Network Configuration Type to Static.

Error -->
"An unexpected communications error has occurred when applying the following settings:
- Control Attributes - DHCP or BOOT.

The following request(s) failed:
- Interface Attributes (IP, Network Mask or Gateway)
- Control Attributes - DHCP or BOOT."

I will also attach photos of these issues.

Any help would be greatly appreciated. I'm trying to teach myself more about PLCs and am at a beginner level.

Thanks.

 

[JleDeLuca]

I'm checking this post frequently and will gladly add more detail or perform further tests to answer any questions that could help get me an answer to my problem.

 

[drbitboy]

I don't see a question in that post, but I assume you are trying to connect to the Micro820 PLC via Ethernet. Is that correct?

What is your level of understanding IP addressing, LANs, gateways, netmasks, etc.?

Do you know the IP address of the Micro820?

Does your PC have more than one network interface e.g. an ethernet adapter (RJ45, typically) and a Wifi adapter?

How are the PC and the Micro820 PLC connected to the same network? Or are they perhaps connected to each other directly?

 

[drbitboy]

How does your PC network adapter normally set, or obtain, its IP address?

 

[JleDeLuca]

I don't see a question in that post, but I assume you are trying to connect to the Micro820 PLC via Ethernet. Is that correct?

My question would be, “Why am I getting an error when I try to disable DHCP on the PLC and change to a static IP address?”

What is your level of understanding IP addressing, LANs, gateways, netmasks, etc.?

My level of understanding is very basic with respect to IP addressing, LANs, gateways, netmasks, etc.

Do you know the IP address of the Micro820?

The IP address is being randomly assigned whenever I connect to the PLC via Ethernet.

Does your PC have more than one network interface e.g. an ethernet adapter (RJ45, typically) and a Wifi adapter?

Yes, I have both.

How are the PC and the Micro820 PLC connected to the same network? Or are they perhaps connected to each other directly?

I’ve connected directly to the PLC via an ethernet cable and I’ve also connected to the PLC via a router by connecting the PLC to a router and connecting to the router Wi-Fi with the laptop.

Thank you for your response.

 

[drbitboy]

I tried the same things with RSLinx Classic and got the same error. That is, I was not able to change the IP address assignment from static to dynamic, or from dynamic to static.

However, when I selected the Micro820 using RSWho through CCW, I was able to [Download] the project, which included changing the IP address, to either static or dynamic (DHCP).

I suspect the issue is that RSLinx Classic cannot modify the Micro820 IP address, even if it can do the same for other Allen-Bradley devices.

My PC and Micro820 PLC are physically connected to my SOHO router via both Ethernet (RJ45/twisted pair); I also have WiFi on the PC, although it is normally disabled. The nominal IP address range on that router is 192.168.0.0/255.255.254.0, and both the PC and Micro820 PLC get their IP addresses via the DHCP server in the router. So all the network adapters are in the same Layer 2 (Ethernet/WiFi broadcast domain.

I was able to move the Micro820 to 169.253.213.253/255.255.0.0* using CCW and [Download], which disconnected the PC and PLC because they were now on different logical LANs. However, if I then manually assigned the PC WiFi IP address to 169.253.x.y/255.255.0.0*, and also added that WiFi adapter to RSLinx as a second driver (AB_ETHIP-2) driver, I was then able to communicate with the Micro820 via CCW and the AB_ETHIP-2 driver (WiFi adapter), and re-assign the Micro820 IP address back to Dynamic/DHCP via CCW [Download]. After that, I could communicate between PC and PLC via the AB_ETHIP-1 driver (Ethernet adapter).

* N.B. I was not able to manually assign an IP address of 169.254.x.y to the PLC via CCW; I suspect that is because 169.254 is the "link-local" a.k.a. APIPA or auto-IP address range, and CCW would not build a project with such an address.

 

[drbitboy]

... both the PC and Micro820 PLC get their IP addresses via the DHCP server in the router. ...

I should also note that the DHCP server in the router "knows" the MAC Address of the Micro820, and the DHCP server is configured always to provide the same IP address to the Micro820, when the Micro820 is configured to obtain its IP address via DHCP. The router calls this a DHCP address reservation.

 

[drbitboy]

I also have a MicroLogix 1100 on the same network; RSWho does not show [Module Configuration] as an option for that device:

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[ckelly]

is the controller in program mode? if not it will not take changes.

 

[JleDeLuca]

Hello again,

I cannot thank you enough drbitboy, that was the info I needed to get started. I’m back to learning a lot from this Micro820.

Thank you.