Pull-Up Resistor Zn1,Zn2 and Zn3 on M1

Can anyone confirm the surface mount pull-up resistors numbers on the main M1 board. I am only after Zn1, Zn2 and Zn3.

I need to remove them for an analog zone application.

Appreciate if some has this info.

Thanks,

Fleetz

You may be able to determine by following the traces and using a meter to check the zone input side of the resistor. One side of the resistor will be at system voltage and stay there. The other side of the correct resistor should measure system voltage when open, about 7.3 when an EOLR is on the zone and 0 volts when the zone is shorted. There is a post about remiving them on an expander but I haven't seen one for the M1 main board. Maybe some else's google-fu is stronger than mine.

They also may align with the zone inputs on the board in some sort of repeating fashion.

The main board on the M1 allows analog zone definitions, ZT 34.

http://www.cocoontech.com/forums/index.php?showtopic=4350&hl=pull+up+resistor&fromsearch=1

Thanks guys I finished up driving a relay and then feeding the zone input. A little more work but a more robust solution. I thought second about modifying the main M1 board.

Regards,

Fleetz

fleetz said:

Thanks guys I finished up driving a relay and then feeding the zone input. A little more work but a more robust solution. I thought second about modifying the main M1 board.

Regards,

Fleetz

Click to expand...

So you didn't need the voltage reading capability, just a open or closed status? I am trying to follow how you accomplished what you needed in your original post with a relay.

gatchel said:

So you didn't need the voltage reading capability, just a open or closed status? I am trying to follow how you accomplished what you needed in your original post with a relay.

Click to expand...

Good question and don't mind answering it. I am interfacing 3 AC head units where I was able to get a open collector output. I was going to use that voltage variant between when the unit is on and off approx 4V verses 12V to determining the status of the AC using the analog 34 mode.

When I connected the relays the 4V went to zero in the off state because of the relay coil load and when it is on the 12V drives the relay on. I then connected the relay to the respective zone inputs. The relays btw are seperate 12VDC relays not on an ELK expander board.

Little more work but all in all a better more robust out come. Something about a relay contact that can not be misinterpreted.

Regards,

Fleetz

fleetz said:

Good question and don't mind answering it. I am interfacing 3 AC head units where I was able to get a open collector output. I was going to use that voltage variant between when the unit is on and off approx 4V verses 12V to determining the status of the AC using the analog 34 mode.

When I connected the relays the 4V went to zero in the off state because of the relay coil load and when it is on the 12V drives the relay on. I then connected the relay to the respective zone inputs. The relays btw are seperate 12VDC relays not on an ELK expander board.

Little more work but all in all a better more robust out come. Something about a relay contact that can not be misinterpreted.

Regards,

Fleetz

Click to expand...

Got it.Thanks for the update. I also agree about using relays when interfacing with different types of equipment, It gives an extra "layer" of isolation between different voltage sources and can make things easier to troubleshoot if a problem ever shows up.