"Different FRN" - SCP & Floating Point
EMSSTC said:
I was able to change the OS FRN from 6 to 13.1, but I still got the same error. I noticed that there is a processor cat number, series and FRN as well. they are 1764-LSP, series A, FRN 4.0
Is this what needs to be changed?
(BTW: You've typed 1764-L
SP, is the new controller not an 1764-L
RP?)
Just to clarify...
When dealing with controller firmware upgrades for enhancements, it's the
OS (Operating System)
Series Letter and
OS FRN (Firmware Revision Number) that you refer to.
As well as the OS Series Letter, you have the OS Revision Letter. You won't see the OS Revision Letter under the
'Processor Status/Proc' tab. Instead go to
I/O Configuration and double-click on the controller slot 0 to bring up the embedded I/O properties window. Here you'll see
'Series/Rev/Functionality Type:' with the OS Revision Letter.
A controller is usually released at something like:
OS Series A, OS Rev A, FRN 1
Depending on whether the new firmware is adding anomaly or bug fixes, support for new hardware features, or adding new enhancements to the OS,
the FRN will always increment,
the OS Revision Letter will often increment,
and the OS Series Letter will sometimes increment.
A lot of users may seem to "get away with this" WARNING, but just for the record...
The MicroLogix 1500
1764-LSP/LRP OS Series C OS Rev A OS FRN 6 added support for the
Floating Point Data File.
While adding support for the use of Floats, with many different instruction types, it did not add support for the use of Floating Point addresses in the SCP instruction until the release of
1764-LSP/LRP OS Series C OS Rev B OS FRN 7. Something specific was added to FRN 7 to support this method.
The reason RSLogix 500 always displays this WARNING for Series C controllers, is because you are compiling an offline project file, that uses Floating Point Operands in SCP instructions. It is merely forewarning you as it doesn't know the OS FRN of the controller you will be downloading the project to. The fact that it lets you verify and download, does not guarantee that all will be well. If the controller is not at FRN 7 or above, but is at FRN 6, you may run into problems at some stage. Math errors may occur periodically, and unexpectedly fault the controller.
I would always advise that one upgrades the OS FRN to the supported level, or above to avoid such possible issues.
Some might say they have been "ignoring" this WARNING for years without a problem, but they should be noting the OS FRN of the controllers they are downloading to. They may have been lucky enough that it was at a supported level, or FRN 6 hasn't thrown up any problems to date. But it's not worth the risk, especially when the firmware upgrades are freely available.
Now that you know your controller is at OS FRN 13.1, you can certainly ignore the WARNING.
G.