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How to write to an RFID Tag using TracerPlus

If you are looking to use TracerPlus to write RFID tags, this article should be a helpful guide on how to do so. Also be sure to check out the RFID Writer Sample Form on's Mobile Solution page if you want an idea on how it looks.

First thing's first, before we do anything we'll have to get set-up, which means opening TPD, starting a project and labeling everything and setting up a form design. Writing to an RFID tag is going to require two fields and a button at the very least (one field for the RFID number and the other for what you want to write to the tag). So keep that in mind while you design your form and plan out the space for all your fields and buttons you plan to add.

Once you've got your layout, you're going to want to head on over to the Data Capture tab at the top, it’s the symbol with the little signal bars going left and right. When you're in here, you're going to want to check the box which reads "Enable RFID scanner" and make sure its marked, and if it isn't then mark it. If it can’t be marked and you see the android logo instead, you'll have to click on the profile tab and change your OS from Android to Windows Mobile (it's in Project Settings).

Alright, assuming you've made it this far, you'll notice that you've just unlocked a couple of new settings in this RFID menu. The main things to focus on are the Scan stop, Radio Power, and the SmartForm options. We can also tick the checkbox next to "Read user memory during scan", if you want to check what's written on the RFID tag then you'll want this marked. The rest of the options we're going to want to leave alone for now. Let's look at the three options that I pointed out earlier:

Scan stop - There's two settings for this, "TriggerRelease" and "Tag read", these determine when you want to stop the device from scanning. It's best to switch it to "Tag Read" because otherwise we might end up with more data than we want (unless you want more data, then leave it on Trigger Release).

Radio Power - This handy setting allows us to control how strong the RFID reader is. Do we want to read the one tag that’s touching the scanner, or do we want to read every tag in the surrounding area? The lower the setting, the lower the range, but if it's too low the scanner might not pick up the tag. I recommend setting it somewhere between the 6 - 14 range, for best control. 

SmartForm - THIS is important, this is where you determine what you're looking for in the RFID tag and where to show it. You'll want to set the Rule Type to RFID Read Complete, which will read whatever you specify once the device has actually picked up a RFID tag. Next is Value. The EPC option reads the RFID's number, and the User option reads what's been written to the RFID tag already. Next you want to pick where it's going to go. The EPC usually has a Destination Field of RFID, or Tag number, or something along those lines as this value is used to identify the tag. The User option will have a destination field of whatever you're looking for in the RFID tag: dates, locations, secret passwords, whatever you wish. Without this, there is no RFID read. Then finish it off by making sure the "Trigger After Scan" box is marked. This makes sure that after you scan the RFID tag the field is filled, though it does slow down the form a bit so use it if you feel it's necessary. 

Next up, we're going to want to limit the fields on your form, so head on over to the Form Design tab again and we'll get to work on that. Select a field that you want to have written to by the scanner, like the RFID tag number field, for example. In the properties tab on the right, go to where it says data and underneath it, select the drop down for InputType and click 'RFID'. This will ensure that the only way this field gets filled is by the scanning of a RFID tag. 

Now that we've got our tag number coming in and our SmartForm filled in, we only have one more step, Writing to the RFID tag. This is what you're really here for and let's get straight to it. You're going to want at least one field which will have what you want to write to the tag in it, and a button to start the writing. Feel free to put whatever you want for the Field, and you'll probably want to make sure that the InputType for this field is set to 'Any', since this is the field where we'll be entering the data that will get written to the tag. The main and most important part of writing to the RFID tag is the button. This is how we write what we're going to write, this is what starts the writing. So grab that button and let's get to work. Make sure that button says what it's going to do on it if there are other buttons on the form, we don’t want to confuse the buttons. Head over to the "ButtonAction" option under the Behavior category and select "RFIDTagWrite" from the drop down menu. Now look at the RFID category at the bottom of the properties and you'll see three settings:

Tag ID Control ID - This is your value which points to the RFID number of the tag you want to write to. So enter the ID of the field which you designated in your form to hold the RFID number (you can find it by clicking the ID button in your Form Designer toolbar. The Icon is between the lock symbol and the paper with a lightning bolt).

Read/Write Control ID - This is the value which is going to point to what you want to write. So enter the ID of the field that you designated in your form to hold the value you want to write to the RFID tag. If you have more than one value you want to write, you'll have to chain the Write Button to other write buttons using the GoTo Control ID setting and entering the D of another Write Button. 

Tag Memory Bank - This option determines what you write to. If you want the button to edit the RFID's tag number, use the EPC option. If you want the button to edit the data that the RFID contains, then set it to the USER option. 

(Quick note: if the Field holding the RFID number is ID 0, you may want to change that ID number and alter the Tag ID Control ID appropriately, as this has been known to cause issues)

Congrats! That's all you need to do to write to a RFID tag, now you can go and build off of what you've learned here today. Go out and chain some buttons together and write a whole multitude of data to an RFID tag or Chain buttons that can write data to a whole multitude of RFID tags at once, whatever you need to do, now you have the knowledge to do it! (As long as its writing to RFID tags, that is)


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  1. John Townsend (Migrated deleted Agent)

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