rwraley
Dec 22 2005, 11:34 PM
I was reading in the Micrologix user manual that you can connect the 1200 to PC straight with a PM02 cable but they recommend using an AIC. It states this is to provide isolation. What are the ramifications of not using the interface converter. Also if not using AIC and using USB to serial converter do I need a null modem adapter ? because I have not been able to connect with two seperate units. I did try to switch back to default comms (no success)
Wordman
Dec 23 2005, 07:44 AM
Isolation is not really necessary, I woudlnt' buy the adapter soley for the purpose of connecting to my PC.
You shouldn't need a null modem adapter
USB to Serial converters are hit or miss for connecting to PLCs. I've had good luck with Belkin and Tripp Lite for Allen Bradley. I've had even more luck with (haven't found a device I couldn't connect with) the PCMCIA Serial cards
TWControls
Dec 26 2005, 08:37 AM
I have never used the AIC and have never have any problem. I was wondering if there was anyone out there who does use the AIC and could tell some advantages of using it compared to a straight cable. Maybe distance or larger networks?
gravitar
Dec 27 2005, 09:47 AM
Regarding a point-to-point connection, I believe theres a serious-sounding warning in the A-B literature somewhere that if you plug a laptop directly into a controller without electrical isolation, you could create a ground loop and fry your laptop. This caused a big hullabaloo many years ago when one of my coworkers at Mac & Mac photopied the warning and posted it everywhere, and warned every customer he could about it. His heart was in the right place, but I don't think the mass panic was warranted. I'm not gonna say it **CAN'T** happen, but I plug my notebook straight in, no protection, many times every day and have nary a hickup. Nor have I heard any reports of this happening.. and I sold programming terminals (i.e. laptops) at Mac & Mac so I WOULD have heard about it.
Now obviously, the NET-AIC isn't useless. Far from it. If you want to extend your DH485 network further than a C20 goes, you need it. If you want more than two nodes on the network, you need it. If you like lots of flashing LEDs in your panel, you want it :)