Open collector outputs and M1G zones

[Ira]

Set the zone to End Of Line resistors, place the end of line resistor on the zone input, and put the Open Collector output device on the zone side of the end of line resistor, not on the negative side. When the Open Collector device shorts to negative, it will violate the zone input.

I now understand how to wire up Spanky's suggestion, I think. I have a GE Quik Bridge 8016 Loop Receiver which has eight OC outputs which I use for wireless water leak sensors. I didn't consider looking at it earlier as an example because it only has one terminal per OC output, so I figured it was different. Now that I know this new OC output board's "2nd terminal per output" is just a convenience connection for shared grounds, I realize they are logically the same with regard to OC outputs.

The Quik Bridge is powered by the P412 PS, which has a shared ground with the M1G PS (via a connection to the ground terminal on a DBH in the same box). There is only one wire per channel/zone between the Quik Bridge and the corresponding M1XIN zones. According to the Quik Bridge manual, this is a non-supervised loop connection, and the M1G zones are set to Normally Open. The manual shows two additional wiring diagrams, both with EOL resistors in them, and both with a single connection from the OC output to its corresponding M1G zone positive terminal. The "supervised N/O loop" has the EOL resistor in parallel, i.e., directly between the zone's positive and negative terminals. The "N/C Loop" shows the EOL resistor in series with the positive connection between the OC output and the zone's positive terminal, with nothing directly connected to the zone's negative terminal. Since the OC output board will be located within a few inches of the M1XIN board, I don't know of any reason to use EOL resistors, although if I can find some laying around, I guess there's no reason not to use them.

Ira

 

[gatchel]

The board manufacturer recommends separating their boards from other devices' PS's, unless you put in other stuff to control transients, surges, etc. I guess they consider their stuff to be on the "sensitive" side.

I would abandon that device solely based on that statement.


This is where isolation becomes very valuable.

 

[apostolakisl]

I would abandon that device solely based on that statement.


This is where isolation becomes very valuable.

I disagree. Every manufacturer is going to say this. It is cya statement. No one would encourage you to share with random unknown stuff made by other co's, that would totally set them up for liability.

 

[KeepItSimpleStupid]

This whole post is confusing.

O.C. basically means a solid state switch to ground. Contact closeures to ground have been a great way of communicating on and off signals.

If this were a relay, one would have to worry about:
a) operate time
B) release time
c) max voltage
d) wetting current
e) switching current
f) load current
g) inductive/resistive
h) max voltage
etc.

When you have an OPEN collector output, you have
a) A max voltage to worry about
B) A diode drop to worry about.

These guys make a nice relay board: http://www.winford.com/products/rlp104.php and I'm using it with a LINEAR 8 channel DXS receiver. I suggested to them that they modify thier input terminals and include two (+) and two (-) terminals. They did incorporate that into their new board. The mod makes it easier to daisy chain. Diode protection is built in to their board.

The beauty with Open collector is that your device could have a 5 V supply, but your interfaced device ( a relay) could have a 24 V supply. Optocouplers of the FET and transistor variety can provide isolation.

Who knows where those smilely things came from?

 

[gatchel]

I disagree. Every manufacturer is going to say this. It is cya statement. No one would encourage you to share with random unknown stuff made by other co's, that would totally set them up for liability.

I can agree with your reasoning.

I have been to factory / manufacturer traing on over 10 different access control systems and several CCTV and IP systems. When the question about interfacing with "other" manufacturers systems has come up, relays were always suggested.

I am not saying that using OC outputs is wrong, it will probably work just fine if done correctly. I feel and others in my industry feel the the relay is the better way to do it.

A far as a relay being more complicated and having more steps I completely disagree. The minute you do something "wrong" with an OC output it is trash. You'll then have to repair things on a circuit level "inside the box". While relays might take a few more milliseconds to activate, they are much more forgiving to voltage spikes, small overcurrent spikes, etc. If you are worried about the coil breakbown spikes on a relay, that can be resolved with and $0.10 diode.

In the long run the relay is the simpler way to do things.