Anthony Trudeau

European UHF duty cycle with the iMotion Edgeware

The 5.1 version of the Globeranger iMotion Edgeware platform indirectly supports the European UHF duty cycle.  The European Telecommunications Standard Institute (ETSI) provides rules for a 10% duty cycle for UHF transmissions.  Essentially, in my understanding, this rule means that any device cannot generate UHF signals for more than 10% of the total time it's on.

The new version of the platform introduces RF control options to the reader controller registrations.  This new functionality is implemented by means of a RF Control tab on the Reader Controller Registration dialogs.  The tab includes start and stop conditions that provide for a simple interval/duration or the more advanced triggers using a binary device.

The simple interval/duration allows you to specify how often the reader should start sending a signal (repeat period) and how long the signal should be sent (duration interval).  These options could provide a simple way to enforce the duty cycle.  For example, you could specify a repeat period of 60,000 ms (1 minute) and a duration interval of 6,000 ms.  Simple math shows that this is 10% since the timer for the repeat period starts immediately after it starts the duration.  (You could specify a continuous interval by specifying a repeat period of 5,000 ms and a duration of 5,000 ms.  Of course there would be no point in doing this.)  A good example of where this might be valuable is in monitoring the inventory of a stock bin.

The more advanced option uses triggers for starting and stopping the reader.  You can specify start and/or stop triggers which require that at least one binary device (such as a photo eye/beam) be defined.  A convenient wizard was designed to allow the creation of the triggers.  The wizard is very simple.  You specify your device group name and indicate either on or off for the state to execute the trigger on.  There are additional options for determining when exactly the trigger will execute.

Using a binary device as a trigger for the reader to start is the best option for a lot of scenarios such as for a dock door.  In this scenario, you may be doing all of your shipping or receiving at certain times which would make a specific interval unworkable.  The following scenario could be defined to cause the reader to read for 10 seconds after a binary device (such as an IR beam) is broken.

1. Create a reader registration
2. Create a binary device registration
3. Create a binary device controller
4. Create a reader controller and specify the following RF control settings:
   1. Duration interval = 10000 ms
   2. Start trigger (state = Off)

You can test this scenario using the Visual Device Emulator using these steps:

1. Drag a Simple Reader on the canvas, and set its:
   1. ID
   2. IPAddress
   3. Port
2. Drag any antenna on to the canvas, make sure the ID of the antenna matches the antenna for the reader
3. Link the antenna to the reader
4. Drag a Simple Binary Device on to the canvas, and set its:
   1. ID
   2. IPAddress
   3. Port
5. Drag a Binary Device Beam onto the canvas, set ShowLabel = false
6. Link the beam to the binary device
7. Add any type of tag on to the canvas

Your device emulator canvas should look something like this:

After you start the emulator you will notice that as you drag the tag down into the beam that the reader will start.  After 10 seconds it will stop.  Break the beam again and the period starts again.

The RF control options I discussed in this article are a much welcome addition to the iMotion Edgeware platform.  Prior to this release RF control had to be implemented solely with hardware. 

Print | posted on Tuesday, February 21, 2006 11:56 AM |