How to connect an "Open collector -ve switching" output to a CCI input

Thread Starter

Robert Dunkley

Joined Dec 1, 2018
4
Hi all

First up I'm a software guy and don't know much about circuits at all so if this is a stupid question I apologise. I'm trying to connect this external PIR http://www.gjd.co.uk/sites/default/files/pdf-files/opal_xl.pdf to a CCI input on this IO box http://www.lutron.com/TechnicalDocumentLibrary/qse-io.pdf

The PIR is fed from a 12V DC supply which I checked and is showing 13.5V DC (So within range) and I connected the "No1 Output" on the PIR to the CCI1 on the IO Box but nothing was detected. I have verified the CCIs on the IO box do work with a simple switch. I have a feeling I either need to involve the DC ground with the IO box somehow or maybe another component is needed to make this work but would really appreciate any advice.
 

Reloadron

Joined Jan 15, 2015
5,501
They do need to share DC common (-).

On your PIR sensor it looks like both the #1 and #2 (A & S) outputs are open collector meaning when active they make a connection to common. On page 4 of the PIR Sensor data sheet they show examples of relays connected across the PIR outputs and mention a minimum relay coil resistance 470 Ohms with 12 VDC applied which implies maximum current of 25 mA (0.025 Amp). I would replace where you see the relay coil with a 10 K resistor to act as what is called a pull up resistor for the open collector out. This goes between the A or S open collector outputs and your 24 volt supply. The diodes are not needed as shown. When active the logic out will be about 0 volts and when inactive about 24 volts into your IO.

Hopefully another member will chime in as I am seeing the open collector out of the PIR as a NPN open collector out. The 10K will have the PIR sinking about 2.4 mA.

Ron
 

ericgibbs

Joined Jan 29, 2010
10,188
Hi,
I agree with Ron, the 0v lines must be linked.
The d/s shows a 12Vdc 470R relay, driven by a NPN transistor output, thats approx 25mA.
E
 

Thread Starter

Robert Dunkley

Joined Dec 1, 2018
4
Thank you for the response both. I found a bit more information on the QSE-IO open collector support:
• Inputs must be dry contact closure, solid state, open collector, or active-low (NPN) / active high (PNP) output – Open collector NPN or active-low on-state voltage must be less than 2 V- and sink 3.0 mA – Open collector PNP or active-high on-state voltage must be greater than 12 V- and source 3.0 mA

This may sound stupid but is this the wiring you suggest?:
PSU +12V to PIR
QSE-IO Common to PIR GND
QSE-IO Common to PSU GND
PIR Output "A" to QSE-IO CCI1
10K Resistor between Output "A" and 12V Line?!?
 

Reloadron

Joined Jan 15, 2015
5,501
Here is a potential problem I see. Looking at your IO on the inputs:
"Five Input Terminals • Accept maintained inputs and momentary inputs with 40 msec minimum pulse times • Off-state leakage current must be less than 100 μA • Open circuit voltage: 24 V- maximum • Inputs must be dry contact closure, solid state, open collector, or active-low (NPN) / active high (PNP) output – Open collector NPN or active-low on-state voltage must be less than 2 V- and sink 3.0 mA – Open collector PNP or active-high on-state voltage must be greater than 12 V- and source 3.0 mA"

My read on this is that to see an active high logic level the input must exceed 12 volts. I would connect the 10K resistor high side to your 24 volt rail (24 VDC Supply). Rather than connect one side of the 10K resistor to 12 VDC I would sonnect it to your 24 VDC + Supply. That is how I read it anyway.

Ron
 

Thread Starter

Robert Dunkley

Joined Dec 1, 2018
4
Thanks again.

So is this correct?:
PIR output connects to QSE-IO CCI1
PSU +12V to PIR +12V
PSU -12V, QSE-IO Common and PIR -12V all connected together
4K resistor connected between QSE-IO Common and +12V
 

ScottWang

Joined Aug 23, 2012
6,909
Thanks again.

So is this correct?:
PIR output connects to QSE-IO CCI1
PSU +12V to PIR +12V
PSU -12V, QSE-IO Common and PIR -12V all connected together
4K resistor connected between QSE-IO Common and +12V
PIR output connects to QSE-IO CCI1
PSU +12V to PIR +12V
PSU 0V, QSE-IO Common and PIR 0V all connected together
4K resistor connected between the Output "A" or "S" of QSE-IO and +12V.
Connected to "A" or "S" that is depends on what you need.

Single power supply : +12V,0V
Dual power supply : +12V,0V,-12V
 

Thread Starter

Robert Dunkley

Joined Dec 1, 2018
4
They do need to share DC common (-).
Ron
Thank you so much Ron and ScottWang. It seems that is all I needed.

I just connected it up as Scott mentions above but without the resistor; I guess the QSE-IO must have some sort of internal resistor or some other way of dealing with this.
 

Reloadron

Joined Jan 15, 2015
5,501
Thank you so much Ron and ScottWang. It seems that is all I needed.

I just connected it up as Scott mentions above but without the resistor; I guess the QSE-IO must have some sort of internal resistor or some other way of dealing with this.
Surprised it works less the pullup resistor but if it works then fine.

Ron
 

ScottWang

Joined Aug 23, 2012
6,909
I just connected it up as Scott mentions above but without the resistor; I guess the QSE-IO must have some sort of internal resistor or some other way of dealing with this.
I'm glad to hear that.

The unknown status is not a good thing, so I tried to find out the input circuit of QSE-IO from the user manual, but I can't find it, so I just followed and reduced the vales of pull up resistor that you mentioned (it also shown in the post #5 by Eric), sometimes if there is any resistor existing at the input of QSE-IO and when you add the pull up resistor then it will be become a voltage divider, the input voltage level will be decided by two resistors.

The only message shows that the input of QSE-IO needed was shown in the post #5 by Eric and that is dry contact, so the unknown or can't make sure the status then the only way is to through try and try again.

If the input of QSE-IO is an NPN stage then the pull up resistor and the internal resistor of QSE-IO could be a voltage divider, If the input of QSE-IO is an PNP stage then the pull up resistor and the internal resistor of QSE-IO could be in parallel.
 

ericgibbs

Joined Jan 29, 2010
10,188
Hi,
Re-looking at the Input spec of the QSE, it states the input signal can be a dry contact closure or a NPN, which indicates an internal pull up resistor to +24Vsup, so no external resistor required.
A possible problem is the OPAL output, as the device is rated 15Vsupply max, so will its output transistor tolerate 24V on its Collector.??

E
AA1 03-Dec-18 08.33.gif
 
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