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Some commands use these codes to identify which real-time check(s) should be performed for a particular SPC standard:
Python command stdspc.rtcheck
Template commands for XML and the Record Buffer
Template command SETRTCHK
Other commands use these codes to identify which real-time failure(s) occurred in one SPC data record:
Python command dataspc.rtf.calculatertfvalue()
Python command dataspc.rtf.value
Python command statspc.data.rtf()
Python command inspect.cursubi.ni(idx).rtfvalue
Python command inspect.cursubi.ni(idx).rtfcelloverrides
Python command inspect.cursubi.ni(idx).rtfsubgroupoverride
Template command RTF_STATUS
Each real-time check / real-time failure has a numeric value.
256 |
X above individual limit |
512 |
X below individual limit |
1024 |
X above specification |
2048 |
X below specification |
1 |
X-bar above control limit |
2 |
X-bar below control limit |
4 |
R above control limit |
8 |
R below control limit |
16 |
X-bar above gate |
32 |
X-bar below gate |
64 |
R above gate |
128 |
R below gate |
4096 |
X-bar run above mean |
8192 |
X-bar run below mean |
16384 |
R run above mean |
32768 |
R run below mean |
65536 |
X-bar trend increasing |
131072 |
X-bar trend decreasing |
262144 |
R trend increasing |
524288 |
R trend decreasing |
1048576 |
2 of 3 above 2 SD |
2097152 |
2 of 3 below 2 SD |
4194304 |
4 of 5 above 1 SD |
8388608 |
4 of 5 below 1 SD |
16777216 |
CuSum above limit |
33554432 |
Cusum below limit |
Multiple real-time checks - or multiple real-time failures for one data record - are represented by adding the individual failure codes together.
Example 1:
To set up real-time checking for both "X-bar above control limit" (1) and "R above control limit (4)", you should specify the number 5 (1+4).
Example 2:
To set up real-time checking only for control limits and specification limits, you would calculate the final value like this:
Combined failure number = (X-bar above control) + (X-bar below control) + (Range above control) + (Range below control) + (X above spec) + (X below spec)
Combined failure number = 1 + 2 + 4 + 8 + 1024 + 2048 = 3087
When summing values to produce a Combined failure number, you can use a "Bitwise or" in your Python code or Template code to ensure that each value only gets added one time. The symbol | is used to perform this operation.
For example:
Python code to add the number 1024 ("X above spec") to a variable sum_failures (that contains an intermediate sum of failure codes) could be written like this:
sum_failures = 1024 | sum_failures
The result:
If 1024 had already been added to the sum_failures variable, then the value of sum_failures would not change.
If 1024 had not yet been added to the sum_failures variable, then sum_failures would be updated to equal its original value + 1024.
The easiest way to determine whether a Combined failure number contains a specific failure code is to use a "Bitwise and".
When querying a Combined failure number for a specific failure code, you can use a "Bitwise and" in your Python code or Template code to find out whether that failure code was added to the Combined failure number. The symbol & is used to perform this operation.
For example:
Python code to check for the number 1024 ("X above spec") in the variable sum_failures (that contains the sum of the failure codes) could be written like this:
if (1024 & sum_failures) == 1024:
print "Data failed the test for X Above Spec"
else:
print "Data did not fail the test for X Above Spec"
The result:
If 1024 had been added to the sum_failures variable, then the operation 1024 & sum_failures would return the number 1024.
If 1024 had not been added to the sum_failures variable, then the operation 1024 & sum_failures would return the number 0.