Published: February 12, 2008
Sporadic erroneous analog module readings possible with some M4RTU controllers
Problem was discovered in version: Rev. 2 Manufactured July 2007 to January 2008
Problem is corrected in controllers manufactured: February 2008 and after
When two analog modules are placed adjacent to each other on an M4RTU I/O board, it is possible for a sporadic, erroneous value to occur and then to correct itself. The erroneous reading may occur on either module. The erroneous value may be up to 20% more than the expected value, and may occur on either an input or an output module.
How to identify Rev. 2 controllers
Controllers with the newer CPU have a white label with "Rev. 2." The label is adhered to the green printed circuit board below the top controller cover, between the digital and analog modules.
Moving analog modules apart, such as installing one in analog position 0 and one in position 2, but not one in position 1, eliminates the problem. Also removing an adjacent analog module prevents the problem from occuring.
Opto 22 had resolved this issue. If you are experiencing the above symptoms, contact Opto 22 Product Support for a repair authorization and an RMA number.
Contact: Opto 22 Product Support.
Phone: 800-835-6786 or 951-695-3080
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