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What are IO ports for?

I can understand the uses of serial, IR & relays but are IO ports used that regularly in automation projects?

What sort of control will it provide?
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Comments

  • IO ports you can use for example as contact closure switches. You can use them in the same way as you do with you panel buttons.
    see the sample below

    DEFINE_DEVICE //ni-3000

    RELAY = 5001:8:0
    INPUT = 5001:17:0


    DEFINE_PROGRAM

    PUSH[INPUT,1] TO [RELAY,1]

    Good luck
  • champchamp Posts: 261
    You can also use it to detect voltage inputs where 0-1.5 VDC is a Push and 3.5-5 VDC is a Release.

    You can use them to read the output of a VSS2 Video Sync Sensor to tell if a TV is on or not.

    Some audio devices have 0-5VDC outputs on them which can be set to go high on certain circumstances like clipping or mute feedback.

    You could also make a ladder circuit to do a basic analog to digital conversion.
  • jjamesjjames Posts: 2,908
    We use them to sync cable boxes and satellite boxes that don't have discreet on/off commands. So that when I write a very simple IF statement, I can guarantee to power it off and on.

    IF(![dvIO,1]) // IF THE CABLE BOX IS OFF & AND WE WANT IT ON . . .
    {
    SEND_COMMAND dvCABLE,"'SP',9" // SEND POWER TOGGLE COMMAND
    }

    or . . .

    IF([dvIO,1]) // IF THE CABLE BOX IS ON & WE WANT IT OFF . . .
    {
    SEND_COMMAND dvCABLE,"'SP',9" // SEND POWER TOGGLE COMMAND
    }
  • I use mine to detect an 'access granted' pulse from the security system before allowing any access to the panel. These I/O ports have many uses as mentioned above. I have even been able to use then to pulse a LV screen controller when there was no relays left or none at all(NI-700). Pretty well endless possibilities of uses.
  • DHawthorneDHawthorne Posts: 4,584
    They can also be used as an output signal (hence to O in I/O). You can turn them on and off (or pulse them) just like a relay if you have an application that uses a 5V trigger instead of a dry closure like the relays provide. Sure, you can do this by feeding your voltage through a relay, but sometimes it's just more convenient to use these as is, just as long as the voltage and current draw limitations are within acceptable parameters.

    That said, I mostly use them for monitoring the on/off state of components, either with a VSS or a devices output relay, or a current sensor of some type.
  • hodeyphodeyp Posts: 104
    thanks all, very useful!!

    what is a dry closure btw?
  • hodeyp wrote:
    what is a dry closure btw?

    AKA contact closure - a good old-fashioned switch or pushbutton, or contacts on a relay...

    - Chip
  • hodeyp wrote:
    thanks all, very useful!!

    what is a dry closure btw?

    Dry = no voltage present

    Closure = switch
  • another good use for D I/0

    Hi Another good use is PIR motion sensors for rooms you have lots of equipment in.. i.e. an example would be people forgetting to turn equipment off in the rack when leaving work, therefore projectors are left running etc.. you could use the input from the motion sensor to check if the room is in use, if not then a wait that you have running in your code would be cancelled and if you AND this with the internal clock time you could check if it is late in the evening.. if all TRUE it shuts the equipment down (standby etc) for you so that it not powered all the way through the night wasting your lamp hours.

    NB use Button_Event[DvTp,0] for running your timer under then any push from the dvTp will start your timer running again, also take lunch time or breaks into your calculations when picking your time for you wait!!
  • Motion detector caution
    Hi Another good use is PIR motion sensors for rooms...

    Be carefully when monitoring many motion detectors (say 10 or more) in a large system where the motion detectors cycle frequently. I had an experience last year where the Event stack became full from excessive push/release events generated by motion detectors. Once the Event stack fills, the NetLinx Master will shut down due to insufficient memory.

    The solution at the time was to off load the motion dectectors and associated code to a second NetLinx Master. I was able to monitor at least 40+ motion detectors without a problem.

    Try to specify motion detectors that don't reset so quickly.
  • annuelloannuello Posts: 294
    PIR motion sensors

    In our lecture theatres we wire 2 PIRs in series since they have normally-closed contacts. They are all wired into a single I/O port. If motion is detected by ANY of the sensors it only causes a single event. If a second sensor is activated prior to the first one closing, the circuit is still open so no secondary event is creted. Not useful if you want to log people's actual movements in the room ("Which door did they use?"), but it is fine for our purposes. ("Any one there?") I've set up our theatres to shutdown after 90 minute of no PIR motion or TP pushes.

    It seems to work well, though the media class get upset when watching a 2 hour film. To avoid this and maintain common code across our theatres, I've put in a flag (in our hidden admin pages) to enable/disable the PIR shutdown. The PIR is still used to bring on the house lights when someone enters the room AND the system is in the standby state. This has reduced the number of bruised-shins-in-the-dark from people leaving furniture near the door. In addition, if the system is in standby and there is no PIR motion for 5 minutes, the lights are then turn off automatically. A countdown on the TP indicates the time before light-off.

    Another use for I/O ports that I'm considering is logging when the service panels on our desks are opened. That way I know when others (techs from various departments) are looking in the desk. Sometimes things get changed without people letting me know. Now the daily logs (emailed to me) will give me an early warning for my 7am shift.

    Roger McLean.
  • hodeyphodeyp Posts: 104
    cheers guys, can I ask about wiring?

    If I wanted to use the pir sensor, how do I wire it up? I am using an NI3000.
  • wiring

    Hi HodeyP,

    Wiring is usually pretty simple, there are quite a few Motion sensors on the market (see google) that require, different supply voltages, the ones i've used on installs are 12V DC supply units therefore it usually comes with it own DC powersupply.
    As far as picking up the switching i.e. motion in the room. There is usually a single wire that provides TTL type switching, ie. goes high to 5v when movement detected. This is what you will wire to into you IO port. You need to know whether you are looking for open circuit or short circuit switching though, AMX allow us to configure each input depending on what we are looking for. NI-X000 manual Pg123.

    I've written and attached some code that shows this working for you .all you will need is a wire or paperclip to short the pins on the back of the NI-X000 processor to simulate a switching input.

    i Hope this helps.
  • hodeyphodeyp Posts: 104
    thanks, is there any way to provide power from the i/o port itself?
  • DHawthorneDHawthorne Posts: 4,584
    hodeyp wrote:
    thanks, is there any way to provide power from the i/o port itself?
    No, you either have to supply them with 5VDC or a closure to ground. There is a 12VDC output on the chassis, but that is too high. If you really needed to, you could drop that down with a resistor and loop it through your triggering device to provide the 5VDC.
  • hodeyphodeyp Posts: 104
    sorry, i'm not an electronics expert. Not sure what closure to ground is. I plugged a wire directly from port 1 on the IO into ground and it switched the port on.

    I am presuming there is some level of current coming from the IO port itself to create a circuit when connected directly to ground. is this enough to power a switch or PIR?

    sorry for all the newbie questions, i am fully setup on my home cinema now and am exporing what else i can get my amx system to do!!
  • DHawthorneDHawthorne Posts: 4,584
    hodeyp wrote:
    sorry, i'm not an electronics expert. Not sure what closure to ground is. I plugged a wire directly from port 1 on the IO into ground and it switched the port on.

    I am presuming there is some level of current coming from the IO port itself to create a circuit when connected directly to ground. is this enough to power a switch or PIR?

    sorry for all the newbie questions, i am fully setup on my home cinema now and am exporing what else i can get my amx system to do!!
    What you did was close it to ground :) - closure to ground = direct connection to ground. Yes, there is a minimal voltage supplied by the IO port to allow this to work. I don't know what it is, but you could slap a meter on it to find out. The IO ports are designed to work either this way, or to detect 5VDC applied to them. If whatever you are sensing supplies a "dry" closure (no voltage at all), you can connect it between ground and the IO port and you are in business. If it has a 12VDC output (the most common I have seen), that is too high to put directly on the port, so you have to use it to trigger an external relay, then use the closure on the relay to connect the ground to the IO port. Devices with a 5VDC output are rare from what I have seen.
  • there is a 12V on the I/O port on the rear so you would have to find a matching Motion sensor that works on this voltage, also if you are going to power it from the NI-X000 you will need to know the current consumption of the motion sensor, this way you can calculate correctly the PSU for the processor as you don't want it or them draw more current than the processor PSU can supply. you need to keep the voltage from the PSU above 12V (most AMX PSU's if you monitor them with a DMM on the back of a NI-X000 will be around 13.5V).
  • VladaPUBVladaPUB Posts: 139
    hodeyp wrote:
    thanks, is there any way to provide power from the i/o port itself?


    Yes, is there a way ??
  • DHawthorneDHawthorne Posts: 4,584
    VladaPUB wrote:
    Yes, is there a way ??
    There is 5 VDC on the port. It is limited to 200 mA. Going low is a push, high is a release (so a short to ground is ON, and if you are using voltage, you drop the voltage to go on). IF you are using it as an output, this is also the case - OFF is 5 V, ON switches it to ground (all this is in the NI-xxxx manuals on AMX.com).

    Very few devices I have seen will operate on 5 VDC, most are 12. I pretty much always use an outboard 12VDC relay, and just short the IO to ground with the relay contacts, unless, of course, I am using a PCS or VSS, or other AMX box explicitly designed to work with the IO port.
  • Anyone use the status output of a Furman power conditioner connected to an AMX I/O port - to monitor the state of the conditioner?

    The status pin puts out 12v. I came across AMX tech note 777 which says that for sensing the on/off state of a 5 to 12v input, a 2k resistor should be tied across the I/O port pin and ground.

    Looking to see if anyone has actually had experience implementing this...

    Thanks,
    - Chip
  • DHawthorneDHawthorne Posts: 4,584
    Chip Moody wrote:
    Anyone use the status output of a Furman power conditioner connected to an AMX I/O port - to monitor the state of the conditioner?

    The status pin puts out 12v. I came across AMX tech note 777 which says that for sensing the on/off state of a 5 to 12v input, a 2k resistor should be tied across the I/O port pin and ground.

    Looking to see if anyone has actually had experience implementing this...

    Thanks,
    - Chip
    If I have the choice, I'll' use the 12v to trigger a relay and use the IO port as a dry closure. I've done the resistor thing though, and it does work. I just prefer to isolate it in the event of funny ground paths.
  • viningvining Posts: 4,368
    We normally do the same as Dave but we also add a signal diode as illustrated and describe below. We also haven't been able to get the Niles Light sensors to work reliably w/o them so it's now a standard item.

    Protection diodes for relays
    Signal diodes are also used with relays to protect transistors and integrated circuits from the brief high voltage produced when the relay coil is switched off. The diagram shows how a protection diode is connected across the relay coil, note that the diode is connected 'backwards' so that it will normally NOT conduct. Conduction only occurs when the relay coil is switched off, at this moment current tries to continue flowing through the coil and it is harmlessly diverted through the diode. Without the diode no current could flow and the coil would produce a damaging high voltage 'spike' in its attempt to keep the current flowing.

    Diodes:
    General purpose signal diodes such as the 1N4148 are made from silicon and have a forward voltage drop of 0.7V.

    Germanium diodes such as the OA90 have a lower forward voltage drop of 0.2V and this makes them suitable to use in radio circuits as detectors which extract the audio signal from the weak radio signal.

    Link to source: http://www.kpsec.freeuk.com/components/diode.htm
  • Diodes across relay coils
    vining wrote:
    We normally do the same as Dave but we also add a signal diode as illustrated and describe below.

    Wow! This takes me back to when a control system was a large custom chassis loaded with relays and hardwired to the boardroom lectern control panel. The youngsters just getting started with control systems don't know how good they have it. :)
  • DHawthorneDHawthorne Posts: 4,584
    vining wrote:
    We normally do the same as Dave but we also add a signal diode as illustrated and describe below. We also haven't been able to get the Niles Light sensors to work reliably w/o them so it's now a standard item.

    The relays I use have the diodes integrated. My preference is the Altronix RB-610, which is actually a circuit board with 6 12V trigger, 10A @ 120VA SPST relays to a board; the board is scored so you can break off a single relay, or however many you need. The board has the aforementioned diode, a jumper to convert it to 24V trigger, and a very convenient screw terminal for the connections.

    The diode really is a must; there are lots of devices that aren't well isolated on their 12V trigger outputs, and the induction caused by the relay closing can totally scramble them. The Niles LS-1 light sensor is a good example - put a relay with no diode on the output of that, and it goes into oscillations when it trips.
  • viningvining Posts: 4,368
    DHawthorne wrote:
    My preference is the Altronix RB-610, which is actually a circuit board with 6 12V trigger, 10A @ 120VA SPST relays to a board;
    I'll have to get some of these cuz I really hate soldering the diodes on the tiny relays we use. It would be worth what ever the cost!
  • viningvining Posts: 4,368
    Thanks Dave, I ordered them immediately after my post.
  • HedbergHedberg Posts: 671
    Just to bring this thread to the top.
  • Using the 12v output and ground...

    I would like to use the 12v output to trigger my Rotel Amp's power switching. The amp has a 12v input (which is actually anything from 3v to 30v). What would be the best way to accomplish this? I'm used to using a relay port, which the 700 doesn't have.
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