Mitsubishi Electric MELFA FR CR800 Series User Manual page 639

The Oscillograph cannot be used when the communication method is set to High speed.
(5)
If you see the message "It can not communicate with the controller." after clicking the [Start Record] button,
please change so that that RT ToolBox3 (MELFA_RT.exe) is allowed to receive in the Windows Firewall
settings.
Check item or cause
Show the following screen by selecting
[Control panel] -> [System and Security] ->
[Windows Firewall] -> [Allow a program or
feature through
Windows7).
Is [RT ToolBox3] in the [Allowed programs and
features] list is the communication range of the
use environment allowed?
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Windows Firewall] (for
Solution
If [RT ToolBox3] is not in the [Allowed programs and
features] list, click the [Allow another program] button.
If the [Allow another program] button is disabled, click
the [Change settings] button first.
Select and add [RT ToolBox3] on the [Add a program]
screen.
Set the check boxes ON according to the use
environment of [Home/Work (Private)] and [Public].
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