Profile and Flatness Dimensions

huangyhg

<< Neil Capper  --  10/07/09  16:31:25>>
the customer is a multi seat customer and has recently upgraded to PCDMIS 2009 and is seeing issues with profile and flatness dimensions.

we ran a series of tests here in Telford using the same program but using Versions 4.2 and 2009, also changing the registry setting UseISOCalculations set to 0 then 1. When this setting was changed we recreated all dimensions to ensure they were ok.

1. Was the registry setting UseISOCalculations active in 4.2 ?

2. If 4.2 was using the ASME standard and UseISOCalculations is set to 0 in 2009 why is there a difference between 4.2 and 2009 when viewing legacy dimensions?

3. Can you explain why there is a differenc between legacy dimensions in 4.2 and 2009 with UseISOCalculations set to 1?

Steps to reproduce:
Open program test42.prg in version 4.2 and view legacy dimensions.
Open program test2009.prg in version 2009 and view legacy dimessions.
<<END>>

<< Don Turcotte (Development Notes)  --  11/05/09  10:51:42>>
The registry setting UseISOCalculations was active in 4.2.  This registry setting affects only profile and not flatness.
Starting in V4.3, the FCF flatness algorithm was modified to use a min/max calculation (in conformance with both ISO 1101 and ASME Y14.5).  This generally gives a somewhat smaller flatness value than the least squares flatness.  The legacy flatness still uses the least squares flatness for all versions of PC-DMIS.  This calculation is independent of the UseISOCalculations setting.
In PC-DMIS 2009, profile formonly takes into account size when UseISOCalculations is 0 (ASME) or the GD&T Standard selected on the advanced tab of the FCF dialog is ASME Y14.5.  This is also true for legacy profile formonly.  A new registry setting was added (Option\UseSizeForProfileDimensions) to allow the user to  revert to the V42 and earlier behavior for legacy profiles only.  This registry setting defaults to 1 (TRUE) so the user must use the SettingsEditor.exe to change this to 0 (FALSE).  When (Option\UseSizeForProfileDimensions) is set to 0, the legacy profile formonly will ignore size.  However, the FCF profile formonly will always take size into consideration when the UseISOCalculations is 0 (ASME) or the GD&T Standard is set to ASME Y14.5.
When UseISOCalculations is 1 (or the FCF GD&T Standard on the advanced tab of the dialog is set to ISO 1101), the profile reports 2 times the max deviation and formonly profile ignores size.
<<END>>