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Author Topic: Ability to read a CRC of the PLC program  (Read 11265 times)

jcottrill

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Ability to read a CRC of the PLC program
« on: December 14, 2017, 12:44:39 PM »
I am using Do-More to develop an automated test platform using some BRX PLCs.  So far I am very impressed.  In order to ensure process control it is desired to know if a PLC program (or all programs on a given PLC) have changed.  My initial thought is to be able to read a CRC/hash of the programs on the PLC and compare to a known value on boot.  Is it possible to read a value such as this from the PLC's memory? 
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BobO

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Re: Ability to read a CRC of the PLC program
« Reply #1 on: December 14, 2017, 01:11:03 PM »
Not currently. Wouldn't be hard to add.
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jcottrill

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Re: Ability to read a CRC of the PLC program
« Reply #2 on: December 15, 2017, 12:19:31 PM »
Is this functionality that could just be added to the designer or would it also require a firmware update to the PLC?
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BobO

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Re: Ability to read a CRC of the PLC program
« Reply #3 on: December 15, 2017, 12:32:19 PM »
Quote from: jcottrill on December 15, 2017, 12:19:31 PM
Is this functionality that could just be added to the designer or would it also require a firmware update to the PLC?

Firmware. There is already a 32 bit checksum associated with the program that we use for a quick validation. Would probably just publish that to a DST location.
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eman5oh

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Re: Ability to read a CRC of the PLC program
« Reply #4 on: December 19, 2017, 03:46:33 PM »
I have asked this before but will second this request here, and reading the value form a DST location would be a great way to do it.
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BobO

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Re: Ability to read a CRC of the PLC program
« Reply #5 on: December 20, 2017, 10:25:00 AM »
Added. $ProgramChecksum(DST58) will be in the next release of firmware. Don't yet have a specific date for this release, but we expect late Q1 or early Q2.

It's just a 32 bit checksum (not a CRC), but should still be a pretty good indication.
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jcottrill

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Re: Ability to read a CRC of the PLC program
« Reply #6 on: December 20, 2017, 04:54:51 PM »
This is great BobO!  Thanks for the quick action on this.
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