Trouble series-ing on M1G databus

[chrisexv6]

Finalyl at the point where I can start plugging stuff into my Elk setup. Initially had it powered up with just 1 keypad wired directly to the data terminals on the control. Everything worked as expected.

Now Im trying to series in a zone expander. Wired it per the 2nd image on page 12 of the manual ("Diagram for daisy chain connection using 3 or more home run cables....")....I know I dont have 3 home run cables yet, but I will. I figured the same should apply with 2 cables for now. I have it setup so the keypad is the last device, the zone expander is the first device and connects back to the control panel. The keypad (last device) and JP3 on the main board are terminated.

All the connections have been checked and double checked. The expander enrolls just fine, but the keypad keeps showing Lost Comm. RPK shows "keypad trouble", the event log shows "Expansion Module Trouble - Keypad 1"

Any ideas? I have a feeling its a termination thing (since the wiring seems fine) but since Ive done it per the manual Im not sure what to try.

Thanks in advance.

-Chris

 

[chrisexv6]

Strange (and I think Ive read a thread on this before): everything started working if the M1KP was the first item in the chain. Dont have a third item to try just yet but instead of going from control -> zone expander -> M1KP, I went control -> M1KP -> zone expander and everything started working.

I forget what the explanation was in the other thread....I wonder if it had something to do with the hardware/firmware version on the keypad itself?

 

[gatchel]

If your M1 is in the middle, it should NOT be terminated, just the two end devices...


IIRC, the other thread was about a used keypad that worked when close to the m1 but not farther away, the speculation was that the 485 driver in the "problem" device was possibly going bad or damaged...

 

[chrisexv6]

I dont think the M1 itself was in the middle.....I went from the databus connections on the M1 to the zone expander to the keypad. That didnt work. Connected the data bus connections from the M1 to the keypad, then from the keypad wire to the zone expander...that DID work. (the M1KP was in the middle, not the actual M1G control unit)

Im wondering if it had something to do with the fact that I was wiring it up using the setup recommended for 3 or more home run data cables, but yet I only had 2 (I will have 3 or 4 when its all done with so 3+ is the way to go)

 

[gatchel]

OK now you have me confused with the "Diagram for daisy chain connection using 3 or more home run cables" comment.

Are you using a M1DBH?

Regardless of what you have and how they are wired, the termination should only be on the end devices, not the device in the middle. Is that what you have?

What page in the manual are you using? If you are only using 3 total devices they you should only have wiring in place to handle the 3 devices (M1, KP, and the expander). No legs of the data bus should exstend past the termination points.

 

[chrisexv6]

OK now you have me confused with the "Diagram for daisy chain connection using 3 or more home run cables" comment.

Are you using a M1DBH?

Regardless of what you have and how they are wired, the termination should only be on the end devices, not the device in the middle. Is that what you have?

What page in the manual are you using? If you are only using 3 total devices they you should only have wiring in place to handle the 3 devices (M1, KP, and the expander). No legs of the data bus should exstend past the termination points.

I mentioned it was page 12 of the manual BUT for all I know I have a different revision of the manual so it could be in a different spot of yours. (I dont have the revision number with me right now)

Originally the 2 termination points were the M1 control itself (jp3) and the M1KP keypad.

It looked like this: M1G (terminated via JP3) -> zone expander (with "terminate 485 bus" jumpered to NO) -> keypad (terminated on circuit board).

That all didnt work.

What did work: M1 control still terminated (JP3) -> keypad (no longer terminated) -> zone expander (with "terminate 485 bus" jumpered to YES)

 

[gatchel]

Was the KP2 used or new? There was a post just like this not too long ago where it was thought the KP 485 transmitter was weak or damaged. The location made the difference there also.

 

[chrisexv6]

Used, go figure! I tried a KP2 as well and saw the same issue.

Someone mentioned the issue there was possibly a physical distance limit.....the KP1 in this case was tried connected directly to the M1 board and worked fine, over the same exact cable that works with as long as its not at the end of the chain. Figure the wiring in the can added maybe a foot or two.....not so sure its distance related (I suppose it could still be because the keypad was used).

Im more curious if it has something to do with a zone expander.

The manual I have shows wiring keypads with the Data AB and A1B1 connectors connected to each other....I found that strange but tried it both that way and without connecting them together and still no go. Also tried terminated and unterminated for the heck of it, still no go. I have the databus hub on the way which I was actually planning on returning, but I might install it just so I can play around with positioning databus items (especially if it might be a problem as I add more stuff) without having to twist, untwist wires, etc.

BTW, I took a look at the newest M1 manual (on the Elk site), and the wiring diagram I used is Option B on page 12.

 

[Del91574]

Which rev manual are you looking at? The info I have is a '05 manual and the latest rev., but the diagrams are the same. I think you're reading the diagram where it's taking the data return from the prior bus device (A1B1) and feeding it through to the next (AB) at the panel. At the keypad itself, you'd have 2 wires conected to each keypad's data (AB) Inside the can, with the last device on the daisy, you'd have a pair free, not connected to anything and that one would get the termination jumper.


Have you metered the data wiring voltage at the keypad itself?

Have you attempted swapping the keypad at the location with a different one or different bus device to see if the data passes through?

It's sounding like a field wiring issue with the 485 daisy if you have multiple devices that exhibit the same issue, barring a questionable device.

 

[chrisexv6]

I didnt check for voltage or resistance at any point on the databus.....what would I be looking for at the keypad, panel, etc?

I swapped the M1KP out with an M1KP2 and received the same error. I agree its probably something to do with how I wired it but no amount of re-wiring I did would get it to work with the keypad as the last device.

 

[Del91574]

On a single terminated run, you'd see 120 ohms +/- 10%. Voltage I'd have to check, but I want to say it's 12V with a pulse for the data, it's been a while since I had to troubleshoot/meter an M1 bus for proper wiring/voltage.

You should be able to meter end to end on the bus for continuity/opens on data A/B.