I am guessing you mean a PanelView that is connected over a DF1 or DH485 serial connection to the MicroLogix 1400, which in turn is connected through its Ethernet port to an Ethernet network.
The answer is no; MicroLogix controllers do not support any channel-to-channel passthrough functions.
I meant to try to comment on this yesterday when I saw it and ask the similar type question as Eddie did there if it was already connected.
If you have a laptop with the PanelView software I believe you can take it out in the field and do the update with a serial to USB cable. I haven't tried it that way, we had to take all 6 back to the office and update them there (mostly because at the time they had other programs on them and we had to figure out how to reset them as well)
