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elk m1 and jumper terminate on controller

tomtnt

Member
I currently have 1 keypad controller, so JP3 is jumpered on the main ELK board. I want to add another keypad to the master bedroom using a pre-exisitng 4-wire cable. When I add the second controller, will I then jumper terminate each of those keypads or will simply jumper terminating JP3 on the mainboard suffice?
 

Steve

Senior Member
Well, each end of the 485 bus needs to be terminated. If you will have 2 keypads each connected to the bus via the onboard connector with no hubs in the mix then I believe the keypads are considered the ends of the bus and you would jumper each keypad and remove the jumper from the M1. Sometimes this whole bus thing can be confusing even trying to figure out what the 'ends' are. I'm sure Spanky will jump in and confirm but I think I am right.

If it is not right you will see data bus errors on the keypad and things may be flaky.
 

Spanky

Senior Member
If you have an existing terminated keypad and the control is terminated then:

You are installing a second keypad using existing 4 conductor wire, so there is no conductors available for the data return. Terminate the new keypad and remove the termination on the M1 Control. Now the keypads are at the ends of the data bus with the M1 in the middle.


FYI:
Should you want to add a third keypad on 4 conductor wire and the first keypad also has 4 conductor wire, you will need to add a M1DBHR data bus hub for retrofit installation. It recreates 4 data buses to allow for using existing 4 conductor wire.

;)
 

tomtnt

Member
Spanky said:
If you have an existing terminated keypad and the control is terminated then:

You are installing a second keypad using existing 4 conductor wire, so there is no conductors available for the data return. Terminate the new keypad and remove the termination on the M1 Control. Now the keypads are at the ends of the data bus with the M1 in the middle.


FYI:
Should you want to add a third keypad on 4 conductor wire and the first keypad also has 4 conductor wire, you will need to add a M1DBHR data bus hub for retrofit installation. It recreates 4 data buses to allow for using existing 4 conductor wire.

;)
So just terminate the new keypad, not the old one also?

thanks
 

Steve

Senior Member
I think he is saying what I did - the keypads are the ends of the bus and get terminated. The control is not terminated.
 

mustangcoupe

Senior Member
Steve said:
I think he is saying what I did - the keypads are the ends of the bus and get terminated. The control is not terminated.
it depends on how you are wiring the new kepad, there can only be 2 terminations on the bus at one time. If it is a series type of wiring.... then terminate the end unit and the controller but if they are two seperate home runs (in parallel) the terminate both but not the controler. see page 7 of the M1G installation manual
 
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