question

silent-power-australia avatar image
silent-power-australia asked

Cerbo GX resistive tank inputs.

Hi community. I have installed a Cerbo gx on a catamaran. My issue is trying to connnect the 4 tank inputs. If I parallel the sender and earth from the existing gauges to the Cerbo tank inputs I get incorrect inputs on the Cerbo. Is the answer a tank 140 ? I am figuring that when the existing gauges are powered they produce a voltage signal not resistance can any body confirm this and that a tank 140 would be the solution.

cerbo gx
2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

silent-power-australia avatar image silent-power-australia commented ·
Great information thank you. Does the converter change signal to digital ?
0 Likes 0 ·
Show more comments
3 Answers
Paul B avatar image
Paul B answered ·

As far as I am aware you cat parralle the gauges to the cerbo, you would need a separte sender for the cerbo and leave the existimng gauges as they are

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

derrick thomas avatar image
derrick thomas answered ·

You need to determine with a certainty if you have resistance sensors or voltage sensors. The cerbo only works with resistance sensors, and the tank 140 only works with voltage based sensors.

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

silent-power-australia avatar image silent-power-australia commented ·
Yes they definitely resistive 0-190 senders. When hooked in parallel with gauges and Cerbo the resistive values measured are 60-80 ohms. Very weird.
0 Likes 0 ·
pwfarnell avatar image pwfarnell silent-power-australia commented ·
No, it is not weird when you understand how a resistive gauge works. To measure resistance the gauge passes a current through the sender and measures the voltage drop to calculate the resistance. If you have 2 gauges, both are trying to send a current through the sender so the voltage drop gets messed up so neither gauge measures correctly.
0 Likes 0 ·
silent-power-australia avatar image
silent-power-australia answered ·

They are definitely 0-190 resistive senders. When wired in parallel with Cerbo and gauges I get resistance of 60-80

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

derrick thomas avatar image derrick thomas commented ·
Parallel gauges can be used with resistive type sensors, but they are not a simple plug and play. You basically have two options. First, and simplest, is to use a spdt (single pole, double throw) toggle switch. Connect the sensor lead to the COM pole, and a gauge to each of the pole 1 and 2. This way only one gauge reads at a time and the sensor remains accurate. Second method is to install a signal converter for each gauge. (Google it, there are converters specifically made for resistive sensors). You will need to adjust each converter for the correct gauge display. It requires a bit of setup but it is worth it if you want both gauges to display accurately at the same time. I have this setup on my Diesel tank and it works great.
0 Likes 0 ·