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I don't know HOW (induced from other lines?), but some channels with CT's connected, but with no load on them are showing 2 to 5 watts (see screenshots).

Is there a way to micro-calibrate these, or how to fix this?

Thanks... /fj

keywords: calibrate adjust

There are several threads explaining the process and what methods are available to you. You can either do a search or review my install thread which details all of the steps and procedures.

Actually yours WAS exactly what i was looking at, but some screens are getting long in the tooth, and not matching, esp in CT setup screens, etc... and it's getting long and hard (can't search in the actual topic thread, from what i can see)... (that being said, you have done an AWESOME job of describing your setup, and I owe you a HUGE coffee for saving me tons of hours of frustration... THANKYOU THANKYOU THANKYOU... you're actually the reason I GOT this system... (you and Barry Grubb)...

i don't see exactly where you describe calibrating each CT...

Thanks,
Fred

Teken wrote:There are several threads explaining the process and what methods are available to you. You can either do a search or review my install thread which details all of the steps and procedures.

Hello Fred,

On page 30 scroll down to the thread entry named *GEM CALIBRATION / COMPENSATION:* Its about half way down the thread with lots of pictures and details for each step. The only portion I didn't fill out was the *Current Constant* because there was a EDOC I needed to append.

The rest of the steps from simple to more advanced are indicated in that guide. Please let me know if you have further question and I would be delighted to help.

http://www.brultech.com/community/viewt ... &start=290

I would start by trying out the jumper option. Basically, you can add a jumper (piece of wire) between the bottom two ports of the channel will add some resistance to the channel. This will prevent noise from adding misinformation.

Can that be ADDED to pins 3/4 (since the board channels go top to bottom, let's number the block pins 1-4 top to bottom... sound ok?) on a channel with a CT using pins 2/3, or is this only for empty channels?

ben wrote:I would start by trying out the jumper option. Basically, you can add a jumper (piece of wire) between the bottom two ports of the channel will add some resistance to the channel. This will prevent noise from adding misinformation.

jumper.png

johnstonf wrote:Can that be ADDED to pins 1/2 on a channel with a CT using pins 2/3, or is this only for empty channels?

It has to be added to the ports shown in the picture, the other two won't do anything unfortunately.

It can be added inline with the CTs however.

Hi Ben,

I wasn't asking to move the jumper (not sure if it's on pins 1/2 or 3/4 but, more, my questions are):
-is it ok to "add" the jumper on pins shown, AND ALSO have a CT (micro-80) on pins 2/3(middle)
-what are the chances this will fix the problem?
-Does the change between 2,4,8 watts give any clues?

Here's a video showing my low-level noise on a channel with a CT on it, no load on circuit...


Thanks for you help!
Fred

ben wrote:

johnstonf wrote:Can that be ADDED to pins 1/2 on a channel with a CT using pins 2/3, or is this only for empty channels?

It has to be added to the ports shown in the picture, the other two won't do anything unfortunately.

It can be added inline with the CTs however.

johnstonf wrote:Hi Ben,

I wasn't asking to move the jumper (not sure if it's on pins 1/2 or 3/4 but, more, my questions are):

The image I attached is looking at the Unit mounted vertically (the labels near the channel will be upright). The issue with numbers is the pin numbering will look different depending on how the unit is mounted.

johnstonf wrote: -is it ok to "add" the jumper on pins shown, AND ALSO have a CT (micro-80) on pins 2/3(middle)

Yeah, it can be added to any channel.

johnstonf wrote: -what are the chances this will fix the problem?

If it's noise, then pretty good. It should at least reduce the amount of Watts shown.

johnstonf wrote: -Does the change between 2,4,8 watts give any clues?

Based on that chart, it could be bleed coming from another channel. It looks like it's following the profile of something else (assuming nothing was turned on at any point).

Bleed is caused by having a Micro-CT (or Split-30 CT) hooked up to Ports 1,2 or 3,4 of any channel. Our Micro-CTs don't have built-in resistors due to their size. Using the two middle ports of any channel (2,3) puts them inline with a resistor.

Thanks Ben,
So if the CT is on pins 2-3, that puts a resistance load on the CT.
So what does adding a jumper on the two outside pins do?
(does it jumper, and thus remove/negate the resistance??)
/Fred

ben wrote:

johnstonf wrote:Hi Ben,

I wasn't asking to move the jumper (not sure if it's on pins 1/2 or 3/4 but, more, my questions are):

The image I attached is looking at the Unit mounted vertically (the labels near the channel will be upright). The issue with numbers is the pin numbering will look different depending on how the unit is mounted.

johnstonf wrote: -is it ok to "add" the jumper on pins shown, AND ALSO have a CT (micro-80) on pins 2/3(middle)

Yeah, it can be added to any channel.

johnstonf wrote: -what are the chances this will fix the problem?

If it's noise, then pretty good. It should at least reduce the amount of Watts shown.

johnstonf wrote: -Does the change between 2,4,8 watts give any clues?

Based on that chart, it could be bleed coming from another channel. It looks like it's following the profile of something else (assuming nothing was turned on at any point).

Bleed is caused by having a Micro-CT (or Split-30 CT) hooked up to Ports 1,2 or 3,4 of any channel. Our Micro-CTs don't have built-in resistors due to their size. Using the two middle ports of any channel (2,3) puts them inline with a resistor.