View Full Version : ground loop

09/25/2005, 12:06 AM
Im totally confused here.. my staus will not come up if I have my ground loop isolator connected ...Rightwen I remove the ground loop isolater it comes right up .My first thoughtwas to go by anotherground loop isolator ,so after spending another 45.00 bux on another ground loop isolator = same deal ,I have switched to a new computer with the same resaults ,I have replaced the serial cable with no luck ......so what now .I have spent so much money on this system getting it dialed in just right ...ie, direct conects,signal bridges .etc etc etc ...now this ..if I use the computer to controll then my ph and orp is wacked out ..and if i want correct readings on my orp and ph then no computer acess ...
doe anybody know how I can get around this problem

09/26/2005, 10:49 AM
An additional wire is required in the serial connection, when the isolator is in place. The required pinout of the serial extension cable is shown here: http://www.neptunesys.com/hardwareFAQ.htm#CABLE. I'd recommend that you temporarily move the controller next to your PC, and just use our serial cable & isolator. Check that that works and then try the extension cable.


10/10/2005, 04:18 PM
I've been trying to figure out how many of these things we will need to purchase if we go above the Jr. If we have the controller within 2 or 3 feet of the desktop pc, does that mean we will probably only need to use the serial cable with minidin 8 connector / female DB9 connector and probably won't have to purchase the ground isolated serial connector (SERIPC9)?

10/10/2005, 06:03 PM
The Jr. doesn't have a serial port or any type of computer connection. For the AC2 the distance doesn't have much to do with whether or not there is a ground loop. On the AC2 if you are going to have the serial cable permanently connected, then I recommend you get an isolator (SERIPC9).

10/10/2005, 07:50 PM
Correct me if I'm wrong but... what if you use a non-grounded power plug ? I have had some problems like that with robotic equipment which was hooked up to a PC. When a laptop with a power adaptor was used that had no ground pin then everything was fine. Installed a two prong to three prong adapter on the PC and it all worked fine.
Can't see that this would be any different on an AC.

Of course ...not having a ground on a standard desktop might be frowned upon by some people.
Either way, it's a $1 solution compared to a $49 solution ;)

10/11/2005, 11:10 AM
Removing the ground pin on the PC may work, however, I don't recommend it. If the power supply in your PC ever develops a problem, you may get electrocuted.