Author Topic: Unlocking a FX Plc  (Read 5504 times)

Lorne Van Dusen

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Unlocking a FX Plc
« on: September 20, 2017, 06:40:45 AM »
I have been experimenting with embedding a password in the PLC so that once it is connected to a router unauthorized people will not be able to access it. I used as an example U$ = "LOCKPLC" then SETPASSWORD U$
This works perfect however we also use a FP4030MR text display to change setting in the PLC which of course will no longer work when plugged in due to the PLC having the password turned on.
Is there anyway possible to have the text display send out the string to unlock the PLC during power up.
Or is there any way t unlock the PLC if a specific bit is turned on.
Don't worry I have a function that automatically resets the password every day.  

support

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Re:Unlocking a FX Plc
« Reply #1 on: September 20, 2017, 04:00:14 PM »
If you want to prevent hacking from the Internet (since you mentioned router) then you should use i-TRiLOGI "Controller->Ethernet & ADC Configuration" screen to create a password and check the "Use username/password" radio button to "Yes". This password will prevent unauthorized access from the Internet via i-TRiLOGI or the web browser, but will not affect serial device (such as FP4030MR) that has physical connection to the PLC.

The SETPASSWORD keyword is actually a legacy feature in the PLC that is seldom used today. In 1993 when our T100MD and T100MX PLCs were first designed for OEM, the term "Internet" did not even exist (there were networks such as  Bit-net used between universities, but nothing for the public) . Back then the only way to  connect to a remote PLC was to use two telephone lines connected via dial-up modem, one on the PC side and the other on the PLC side. The modems typically ran at 1200, 2400 or up a zippy 9600 bps(!).  Since the modem is connected to a telephone land-line anyone who knows the phone number can dial in and control the PLC using the TRiLOGI software. The SETPASSWORD command was created to prevent unauthorized access by demanding the connecting software presents the unlock password before any further communication is possible.

We still support the SETPASSWORD feature for backward compatibility but it is not really needed today since landline modems can now only be found in the same museum along side the dinosaurs :)
« Last Edit: September 20, 2017, 04:51:53 PM by support »
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Lorne Van Dusen

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Re:Unlocking a FX Plc
« Reply #2 on: September 21, 2017, 11:54:15 AM »
Thank you for the reply as well as the full explanation.
I understood how to transfer the various password setting via the software as I had already used that method
However after re reading the manuals I had come across the description to embed a password within the software and figured that that was a better way to go to insure that one of our people that actually down loads the program would not need to know the master password.
After reading your response I realized that the best way for us is to use i-TRiLOGI software and setup the Ethernet as we do not need to secure the serial port.

As always you reply's are very descriptive and always provide the help that has been requested

Lorne