HAI Inputs - internally connected?

[Desert_AIP]

Looking for verifcation of my suspicions based on behavior I am observing.
Are the + and - sides of the input zones internally connected on an Omni Pro II?
 
I have a 3 wire input going to two zones, one wire (NC and NO) to each + terminal and the COM terminal going to both - terminals.
The contact can only be in one state or the other.  I have it wired to two zones because I want positive confirmation of both states.
 
With the contact in the NC position, I am still getting signal (voltage) down the NO wire, and vice versa.
 
The only thing I can think of is the terminals are connected internally and voltage is travelling down the COM wire across the zone termnials from - to + and out the unswitched + terminal.
 
It appears I may need to wire a blocking diode to prevent this.
If I do that, any idea if the 0.6V drop across the diode will affect the zone recognizing a SECURE state with a 1K EOL?

 

[RAL]

Is the OPII indicating that the contact is closed on both zones at the same time, or are you just measuring voltage at the terminals and thinking that something is wrong because you see a voltage there? 
 
It is normal for the + terminal to have a voltage on it when the contact is open.  When the contact closes, the voltage drops, and that is how the panel detects the closure.  With no EOL resistor, the voltage should drop to something close to 0V.   With an EOL resistor, it would drop to something near the middle of the range, say around 6V.

 

[pete_c]

I always assumed just the negative (-) sides (zones) were connected and would have assumed what you are doing would have provided two autonomous switch replies.
 
I assume that you can only utilize the three wires and cannot add another wire for 4 wires.
 
I would just try the diode and measure the voltage; loop value to see what happens.  I am assuming that the 0.6V drop is the current voltage you see on the wire eh? 
 
I have just typically looked at the loop values.  (closed then would be zero volts or close to zero volts and open would be some voltage that isn't zero volts)

 

[Desert_AIP]

The contact I'm using is only 3 terminal, NO, NC, COM.
But I need to positively sense both states. 
Otherwise I'd just hook it to one zone and assume a NOT READY indication was the other state.
 
The voltage is coming from the output itself (+5VDC), it is driving one of two indicator LEDS that signal the opposite states at the device.
But the terminals also provide a contact output (I guess not "dry" in this case).
 
I originally had it wired as two NO zones, with 1K resistors across the terminals of each zone.
But by connecting the COM terminal of the output to both - terminals, and the zones bridged with EOLs, I was definitely providing a current path back down along the other wire (the "Not Ready" side).
 
So I rewired them as NC zones with 1K resistors in series.  So a SECURE indication should be on the side that is active, e.g., NC and COM connected by the output creating a loop through the resistor.
But I'm still getting a voltage down that other zone, NO in this case. 
The zone terminals are no longer bridged with an EOL, and the output is not connecting the leads together. 
So my only other guess is that current is passsing between the terminals under the board itself.
 
If the - terminals ARE all connected internally, that may be the pathway.
I may be able to move the COM output to the + terminals of the zones.
 
0.6V drop is standard across a diode.   
I haven't measured it yet because I don't want any voltage down the unused line.
And I'd like to avoid adding components if I don't need to.
 
What is happening is both LEDs on the device are lighting in both states, because I am backfeeding the voltage down both lines.
If I disconenct the Omni it functions properly, so I know it has something to do with the way I have the Omni hooked up.

 

[RAL]

I think if I understand your description, you are saying that the NC/NO outputs of your contact are not dry contacts, but rather are active contacts that put out a voltage of 5VDC.  Is that correct? 
 
And you have LEDs connected to these same outputs to indicate the state, correct?
 
Or did I totally misunderstand?
 
The OPII isn't going to like that.  It really wants a dry contact that it can see an open or a short  on (plus the EOL resistor).

 

[Desert_AIP]

So I did some metering.
The device is a watercop valve.
It was working perfectly with the Omni, until I added a remote switch panel.
The valve is up in my attic where the water line emerges from the wall.
But I wanted the remote panel in the garage to visually see the LEDs and manually control the valve.
The Omni has relays and can control the valve as well.

Until I added the remote panel it worked with the Omni perfectly.
After I added the panel, both LEDs were lit regardless of the position of the valve, and as I changed things around the Omni stopped tracking the status properly.

After metering.
I discovered that the output of the valve itself is dry contacts on those three wires.
That is why it was working with the Omni fine.
But when I add the remote panel, the 5VDC (on another contact and used to trigger the shuttle action of the valve) is cross connected at the remote panel and routed back to the COM terminal.
And the two LEDs on the remote panel are connected to each of the other terminals.
So when the valve makes the contact via it's dry outputs, it's connecting a now 5VDC COM terminal to one or the other LED to illuminate it.

The LEDs in the valve don't behave the same as those in the remote panel.
So I may be able to tap them and remove the dry contacts from the remote.
Or I think I may use a 5V relay to route the valve output to the panel and provide some isolation.

Either way, this has been an interesting and frustrating project so far.

BTW. I did get continuity between the - terminals of adjacent zones, but not the + terminals.

 

[RAL]

 So when the valve makes the contact via it's dry outputs, it's connecting a now 5VDC COM terminal to one or the other LED to illuminate it.
 

 
 
If you connected the 5VDC to the dry contacts of the Watercop, and also have those contacts connected to the OPII zone inputs, I can understand why it isn't working.
 
One way to isolate things would be to use the Watercop dry contacts to also trigger a 5VDC SPDT relay in addition to the LEDs, and then use the relay's dry contacts to connect to the zone inputs of the OPII.

 

[Desert_AIP]

I just ordered a two channel 5VDC relay with independent triggers so I can turn the NO/NC output into two independent channels with dry contacts as input to the Omni.  (I only have 12VDC relays on hand right now).
 
Trying to isolate the 5VDC with diodes was proving more difficult than I had originally thought.
 
I'm pretty sure the relay will turn out to be the best solution.

 

[Desert_AIP]

If you connected the 5VDC to the dry contacts of the Watercop, and also have those contacts connected to the OPII zone inputs, I can understand why it isn't working.
 
One way to isolate things would be to use the Watercop dry contacts to also trigger a 5VDC SPDT relay in addition to the LEDs, and then use the relay's dry contacts to connect to the zone inputs of the OPII.

 
 
The Watercop remote panel is what is bridging the 5VDC to the COM terminal in order to alternately light the remote LEDS which are wired to the NO/NC contacts.  Simple design, but it threw a monkey wrench into the entire install.