28 LABELS
28.8 Precautions
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28
28.8 Precautions
Functions with restrictions
The following functions have restrictions on the use of labels.
*1 Global labels can be used as devices by assigning a device.
■Defining and using a global label with a device assigned
Define a global label following the procedure below, and use it when the functions having restriction on the use of labels are
executed.
Since the device area in the device/label memory is used, secure the device area capacity.
1. Secure the device area to be used.
[CPU Parameter] [Memory/Device Setting] [Device/Label Memory Area Setting]
2. Define a label as a global label, and assign a device manually.
3. Use the label defined in step 2 for the functions having no restrictions on the use of labels. Use the device assigned to
the label for the function having restrictions on the use of labels.
■Copying the value of a label used to a different device
If a device cannot be assigned to a global label, copy the value of the label to a different device and use the device for the
function having restrictions on the use of labels.
Since the device area in the device/label memory is used, secure the device area capacity.
1. Secure the device area to be used.
[CPU Parameter] [Memory/Device Setting] [Device/Label Memory Area Setting]
2. Create a program using the label. The following is the program example for copying the data. (The data logging function
uses the data in udLabel1.)
3. Use the device where the data has been transferred in step 2 for the function having restrictions on the use of labels. (In
the program example in step 2, use D0.)
• The number of steps increases because of the transfer instruction. (The scan time increases.)
• Decide the transfer instruction position considering the timing of writing data to the label and executing the
function.
Item Description
CPU parameter • Trigger of an event execution type
program
• Refresh setting among multiple CPU
modules
Use devices because global labels nor local labels cannot be specified for these
functions.
*1
Module parameter • Predefined protocol support function
• Refresh setting of intelligent function
module
• Refresh setting of network module (SB/
SW only)
Use module labels for these functions. Use devices if module labels are not used.
*1
• Refresh setting of network module (other
than SB/SW)
Use devices because global labels nor local labels cannot be specified for these
functions.
*1
Data logging function Use devices if there is a possibility for using these functions because global labels nor
local labels cannot be specified for these functions.
*1
In addition, if a device cannot be assigned to a global label, add the transfer instruction
(copying the global label to a different device) on the scan program so that the instruction
is executed every scan, and use that device.
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