Powerflex ip address disappears

Anyone had any experience of powerflex all of the sudden losing communication due to losing its ip address? The machine had been running for two days, so I know it did have a working ip address for those days.

it would be helpful of you can describe the type of powerflex you have, also any error codes, is the powerflex on a network? what are other devices on a network? was their a power cycle to the system and is that when it lost its IP?

The more info you provide the better answer you will get

Is it possible that the IP address was assigned via BootP and was never disabled after? If you fail to disable BootP after assigning an IP address, it will lose the address when power is cycled.

dbh6 said:

The more info you provide the better answer you will get

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Sorry. I didn't write down the Flex model. Actually someone told me about the problem,and I was too busy to ask specifics. Luckily, after new ip address was assigned, the flex runs good now.

dmroeder said:

Is it possible that the IP address was assigned via BootP and was never disabled after? If you fail to disable BootP after assigning an IP address, it will lose the address when power is cycled.

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Yes, the guy who put in the address originally told me that he could have forgotten to disable bootp.

However, I used a Micrologix1100 often back when I was in school. It always retained its ip address through power cycles. I don't think I ever disabled its bootp because in the Rockwell Bootp program, I always saw it sending bootp requests with its MAC and last IP address.

So, why does Powerflex lose its IP address at power cycles when MLX1100 keeps its ip address? Is that by design?

BOOTP - Bootstrap Protocol

unsaint32 said:

Yes, the guy who put in the address originally told me that he could have forgotten to disable bootp.

However, I used a Micrologix1100 often back when I was in school. It always retained its ip address through power cycles. I don't think I ever disabled its bootp because in the Rockwell Bootp program, I always saw it sending bootp requests with its MAC and last IP address.

So, why does Powerflex lose its IP address at power cycles when MLX1100 keeps its ip address? Is that by design?

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The AB DHCP/BOOTP Utility is not just an interface to assign IP addresses. It acts as an IP address configuration Server.

When you open the utility and receive a request from a device, this is a Client requesting an IP address from a Server. When you assign an address in the utility, you are configuring the Server to establish a relationship with the Client. So the Server will then always recognize the Client i.e. its MAC address, and assign the same IP address automatically.

So the Powerflex and the MicroLogix are Clients of the BOOTP Server. Normally when we assign Clients an initial IP address, the intention is to assign a Static IP address. So we use the utility to disable BOOTP while assigning the address. This prevents the device from clearing it's IP address and sending BOOTP UDP requests upon a power cycle.

If your colleague left BOOTP enabled in the PowerFlex while assigning an IP address, then upon a power cycle, it cleared its IP address and began sending BOOTP requests. If a Server is not there to service these requests, then the Client i.e. the PowerFlex, will never be assigned an IP address.

When you had a computer connected to a MicroLogix 1100 in school, you created a relationship between the BOOTP Server on the computer and the MicroLogix Client. With BOOTP always enabled in the MicroLogix, and the Server running on the connected computer, the MicroLogix could clear its IP address upon a power cycle and request a new IP address from the Server. As you had a relationship already established, the Server would re-assign the same IP address to the Client once again.

I always saw it sending bootp requests with its MAC and last IP address

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You will not receive BOOTP requests from a Client that already has an IP address.

When you looked at the requests list, after powering up, you were seeing the MicroLogix MAC address with its automatically assigned IP address from the Server.

If you did not have the Server utility running, or the computer connected, then, upon a power cycle, the MicroLogix would have cleared its IP address and not have had its BOOTP requests serviced.

The tradesman that understands his tools, understands his craft.

G.

Thank you for the replies. I will always make sure to disable Bootp. So, I know two ways to disable bootp. One with the server utility and the other with the programming utility's channel configuration. ( I have attached two pics) So, if I do one, doing the other is not really necessary?

unsaint32 said:

Thank you for the replies. I will always make sure to disable Bootp. So, I know two ways to disable bootp. One with the server utility and the other with the programming utility's channel configuration. ( I have attached two pics) So, if I do one, doing the other is not really necessary?

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Exactly. Once disabled using either method, the other is unecessary. Both methods are just an interface to the same BOOTP, or DHCP setting. Just be careful though, if you've initially assigned an IP address and disabled BOOTP using the Server utility. If at some point in the future you're using RSLogix 500 to edit the channel configuration, be sure to check the BOOTP Enable option is not ticked before downloading to the controller.

Just to be clear for readers, this is just in relation to disabling BOOTP for a controllers Ethernet port, and not a PowerFlex drive's Ethernet port or comms adapter. Which of course is not configured using RSLogix 500.

G.

You can also use RSLinx to disable BOOTP, and in my experience is more reliable. We had a similar issue a few months back, used BOOTP to issue a static IP address, DISABLED BOOTP from the utility, power-cycle the IP address is gone.

Ended up assigning the IP address, closing the BOOTP utility, opening RSLinx, disabling it there.

Huge hassle.

Paully's5.0 said:

You can also use RSLinx to disable BOOTP, and in my experience is more reliable. We had a similar issue a few months back, used BOOTP to issue a static IP address, DISABLED BOOTP from the utility, power-cycle the IP address is gone.

Ended up assigning the IP address, closing the BOOTP utility, opening RSLinx, disabling it there.

Huge hassle.

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I'd agree that the BOOTP utility doesn't always work and I've had similar problems in the past. For controllers I usually use the serial port and DF1 driver to get online to set the IP address and disable BOOTP.

I just wanted to make a correction to my first reply here. I remembered something...

After a power cycle, the MicroLogix 1100 does retain it's last used network configuration. If BOOTP is enabled, and no Server is present, the 1100 will revert to its saved network configuration. So technically, while BOOTP is enabled, the 1100 does have a static IP address to fall back on.

So to answer your question unsaint32, yes it is by design that it retains its IP address.

G.