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In scanning the revision history AB ControlLogix & FlexLogix PLCs (1756-L55/1794-L34), I encountered a corrected anomaly description that should have been a product advisory from Rockwell (but wasn't):
"The 1756-L55 controllers experience a non-recoverable major fault in approximately 3...4 months of continuous operation".
I normally would publish this issue on such a public forum but it's a critical issue for anybody running a continuous process operation.
In scanning the revision history AB ControlLogix L55 PLCs (1756-L55), I encountered a corrected anomaly description that should have been a product advisory from Rockwell (but wasn't):
"The 1756-L55 controllers experience a non-recoverable major fault in approximately 3...4 months of continuous operation".
This issue exists in:
1756-L55 controllers running firmware versions 15.3 or 15.4 AND
1794-L34 controllers running firmware versions 15.3, 15.4, or 15.5
If I hadn't have noticed this issue, our entire plant would have shut down at some point later this month, causing massive losses due to lost production time alone (not to mention the potential issues resulting from our running equipment stopping unexpectedly).
There is a firmware update that corrects this issure. Alternatively, if you contact Rockwell there is a temporary work-around that disables the feature that causes the failure (an internal .ACD file that they won't release unless you ask for it). This can be applied if you can't just shut-down to flash the firmware (as is the case at the site I'm working at).
Good Luck.
"The 1756-L55 controllers experience a non-recoverable major fault in approximately 3...4 months of continuous operation".
I normally would publish this issue on such a public forum but it's a critical issue for anybody running a continuous process operation.
In scanning the revision history AB ControlLogix L55 PLCs (1756-L55), I encountered a corrected anomaly description that should have been a product advisory from Rockwell (but wasn't):
"The 1756-L55 controllers experience a non-recoverable major fault in approximately 3...4 months of continuous operation".
This issue exists in:
1756-L55 controllers running firmware versions 15.3 or 15.4 AND
1794-L34 controllers running firmware versions 15.3, 15.4, or 15.5
If I hadn't have noticed this issue, our entire plant would have shut down at some point later this month, causing massive losses due to lost production time alone (not to mention the potential issues resulting from our running equipment stopping unexpectedly).
There is a firmware update that corrects this issure. Alternatively, if you contact Rockwell there is a temporary work-around that disables the feature that causes the failure (an internal .ACD file that they won't release unless you ask for it). This can be applied if you can't just shut-down to flash the firmware (as is the case at the site I'm working at).
Good Luck.
