How to Work with Processes > Working with the RFID Processes Group

Process Purpose

The "Tag Locate" process is an asynchronous operation used to physically locate the RFID tag you defined using its "Tag ID" ( a unique tag ID number attributed by the manufacturer to each RFID tag).

This process, essentially, turns your target device's RFID reader into a "tag detector". Ex: The use of the beep combined with the System variable "X_RFID_LOC_DIST" lets the operator know if he is getting closer to the intended RFID tag or moving away from it.

Check the provided "Tag Locate" example at the end of the topic.

This process requires the device's RFID reader to be enabled.

Therefore, use the "Enable/Disable" process (ex: Add the "Enable/Disable" process to the screen's "Ready" action).

Make sure you have already created the required RFID profile(s). See Creating an RFID Profile.

Check the necessary steps to create an RFID program in To Create an RFID Program.

When you add a process, you are required to define its settings. This occurs in the process's properties window which is displayed automatically after having added the "Tag Locate" process.

If any subsequent edition is required, double-click the process to open its properties window and enter the necessary modifications.

Fill in the following options:

RFID Locating
Start	Check this option to start locating the RFID tag.
Stop	Check this option to end the RFID tag detection.
RFID Settings
Profile	Select the appropriate RFID profile from the drop-down. If required, click to create a new profile or edit an existing one. See Creating an RFID Profile.
Tag ID to Locate
Enter the “Tag ID number” of the RFID tag to be located OR click to select the variable that provides that information. (This information is available in the predefined local variable “L_Tag_ID” that is included in the RFID action. See RFID action’s Predefined Local Do NOT use the tag’s TID information to define the tag to be written within this process.
Distance Beep	Check this box to enable distance beeps that help with tag location (the closer the tag, the shorter the interval between beeps).
If Error
Go to	Select a target destination, in case an error occurs, from the drop-down or list. See Detail of a window below. When defining a screen as a target destination (ex: via a “Go to” process), you CANNOT use variables to specify the name of that target screen. You must select the intended screen from the available drop-down/list.

Detail of a window:

"S:Menu" is a screen included in the same program as the process.

"R:Routine_1" is a routine included in the same program as the process.

If required, click to attach any relevant notes to this process. Click it and enter your notes in the resulting text box. These notes will be displayed in the corresponding "Actions" tab or "Process" window (in the "Notes" field) and in the "Developer Report".

After filling in the required options, click to conclude or to abort the operation.

The added process is displayed in the corresponding "Actions" tab or "Process" window.

If you want to use a label as a target destination, you can use the "Auto-Label" mechanism. This alternative to the "Set Label" process allows you to create a label in the properties window of a process - specifically, in the fields used to define target destinations (ex: the "If Error..." type fields). See To Automatically Create a Label.

Use the right-click in MCL-Designer's input boxes to access some related options as well as the general "Cut", "Copy"; "Paste"; "Search" actions (active/inactive according to the current context).

Ex: If you right-click the "Variable" input box (included in a "Conversion's" properties window), you are provided with general editing/search actions and other more specific options such as "Variable Select" (see "Variable Select"); "Variable Insert" (see "Variable Insert"); "Insert Special Character" (see To Insert Special Characters into a Control's Text Input Field) and "Localization Select" (see Localization List).

If you right-click another input box, it may provide other possibilities.

Purpose: To locate a specific RFID tag and, at the same time, view the relative distance between the intended RFID tag and the RFID reader's antenna in the device.

1. Prepare the screen with a "Button" control (A) to initiate the tag localization, another one to stop it (B) and a "Gauge" (C).

Make sure an ”Enable/Disable process is used to enable the target device’s RFID reader and allow the operator to execute the tag location.

Ex: Add the ”Enable/Disable” process to the current screen’s “Ready” action.

2. Open the “Actions” tab of “Button (A)”, add a ”Tag Locate” process and fill in its properties window as follows:

a. Check the “Start” option.

b. Select an RFID profile, in this case, the “<Default>” RFID profile.

c. Define the variable that contains the tag ID number of the RFID tag to be located ("P_Tag_ID").

d. Check the “Distance Beep” option so the operator can use the beep sound during tag location.

e. Select a destination for the workflow if there is an error, in this case, the label “START_LOCATE_ERROR”.

3. Open the “Actions” tab of “Button (B)”, add a ”Tag Locate” process and fill in its properties window as follows:

a. Check the “Stop” option.

b. Select a destination for the workflow if an error occurs, in this case, the label “STOP_LOCATE_ERROR”.

4. Open the “Gauge’s properties window and fill in the options as described below:

a. Set the system variable “X_RFID_LOC_DIST” as the gauge’s value. This system variable’s value range is from "0" to "100".

b. Define the other values/options as presented in the image above.

Below is the expected RFID Tag location behavior within your application (MCL-Simulator sequence):


1. The screen for the RFID tag's localization.	2. The operator has clicked the "Start Locate" button and is moving around with his device (with an RFID reader), trying to locate a specific RFID tag.	3. The operator is moving closer to the target RFID tag - the beep succession and the gauge's value increase.	4. The operator has located the target RFID tag and clicks the "Stop Locate" button to stop the tag's localization.