AC Jr PH reading off about 0.1 when the lights are on

[Whiskey]

Hello all,

I have my AC JR plugged into a PC, and I notice that the reading changes by about 0.1 PH when the lights flip on. I've been compensating for this for a while now but I'd love to have the readings more accurate.

I am using an optical isolator on the serial cable. Is there anything else I need to do to prevent electrical interference from the lights? Like grounding the computer or PH Probe or anything?

Thank you,
Whiskey

[zombie]

Is the change immediate or is there a change of 0.1 pH between the peak during the day and the low point at night? A screenshot of your pH graph and some pics of how everything is hooked up would help.

You might be an engineer if...You have no life and can PROVE it mathematically.

[Whiskey]

It is a sudden reaction, when the lights switch on you can see a drop, and when they switch off you can see a hike every day. The amount may vary, and with the lights on the reading bounces around quite a bit.

Thank you,
Whiskey

[zombie]

Does it do the same thing if you remove the optical isolator from the serial port? its possible that is your source of interference, but it could easily be something else.

[zombie]

You may have already checked this, but you could try unplugging the lights and turning the outlet that they were plugged into on. See if the same result occurs.

[Whiskey]

Does it do the same thing if you remove the optical isolator from the serial port? its possible that is your source of interference, but it could easily be something else.

It gets much worse with the optical isolator removed, this problem is actually why I bought the isolator.

I will give unplugging the lights and flipping the outlet back and forth. I expect I will not have the issue with the lights unplugged because it doesn't do it with any other outlet but I will report back tomorrow when I can be sure.

Thank you,
Whiskey

[Whiskey]

You may have already checked this, but you could try unplugging the lights and turning the outlet that they were plugged into on. See if the same result occurs.

I unplugged the lights without turning off the outlet and observed the same effect, the jump and dive in PH is definitely related to the lights and not the outlet they are plugged into.

Thank you,
Whiskey

[zombie]

One more test to make sure the lights are the interference source and not the outlet. Plug the lights into a different outlet and see if the same phenomenon occurs.

You might be an engineer if...You have no life and can PROVE it mathematically.

[Whiskey]

I don't have a totally different wall outlet I can reach, but I could plug it into the other reciptical in the wall outlet and not the DC8. Will that meet the conditions for this test? Or do I need to pick up an extension cord to get to a totally different circuit?

Thank you,
Whiskey

[zombie]

I meant different dc8 outlet. Was it doing that while plugged into a wall outlet too?

You might be an engineer if...You have no life and can PROVE it mathematically.

[Whiskey]

I meant different dc8 outlet. Was it doing that while plugged into a wall outlet too?

You might be an engineer if...You have no life and can PROVE it mathematically.

I will plug it into the wall outlet and let you know in about a half hour.

Thank you,
Whiskey

[Whiskey]

Unplugging from the DC8 and plugging them into the wall has had no effect, in other words the PH is still artificially depressed.

Thank you,
Whiskey