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Assigning Control Limits

jbakri21

Community Trekker

Joined:

Jul 8, 2016

Hello All,

 

I know that in JMP you are able to assign control limits to a column, but I am wondering if I can assign limits to one column based on the value in another column. I have one column called type which contains either "A" or "B" and another column that contains my data. I would like to assign control limits to the data column such that all the rows of type A have one set of limits and all the rows of type B have another set. Is this possible?

 

Thank you!

7 REPLIES
txnelson

Super User

Joined:

Jun 22, 2012

As you noted, you can specify control limits for a given column.  And you can also specify a Phase Column, and JMP will Calculate independent limits for each phase it finds.  However, there is no way to specify limits to be used for those phases.  So the answer is No, you can not set the Control Limits on a row by row basis.

Jim
tonya_mauldin0

Joined:

Jan 21, 2015

You can specify limits to be used for each phase.  This process is detailed in the following blog:  http://blogs.sas.com/content/jmp/2016/11/14/using-fixedbaseline-historical-control-limits-in-control...

txnelson

Super User

Joined:

Jun 22, 2012

Tonya,
The blog entry you pointed to shows how to use historical limits in a control chart, not the ability to set historical limits for each different phase of a control chart. Did you point to the wrong blog entry, or am I not understanding how to do it?
Jim
tonya_mauldin0

Joined:

Jan 21, 2015

#3 in the blog details how to do this. 

3. Get Limits

The Get Limits method is by far the most flexible method. If you have fixed limits for many different processes, you should use the Get Limits method. If you have different fixed control limits for each phase, you should use the Get Limits method. To use the Get Limits method, you need a data table that defines your limits.

....

txnelson

Super User

Joined:

Jun 22, 2012

Thank you for "teaching an old dog a new trick". This is very nice.
Jim
tonya_mauldin0

Joined:

Jan 21, 2015

In the case of phases, the Get Limits table also needs a column for your phase variable.  Here is an example of a Get Limits data table with phases for the sample data table Diameter.jmp.

 

New Table( "Untitled 7",

Add Rows( 19 ),

New Column( "_LimitsKey",

Character,

"Nominal",

Set Values(

{"_KSigma", "_Alpha", "_Sample Size", "_Std Dev", "_Mean", "_LCL",

"_UCL", "_Std Dev", "_Mean", "_LCL", "_UCL", "_Std Dev", "_AvgR",

"_LCLR", "_UCLR", "_Std Dev", "_AvgR", "_LCLR", "_UCLR"}

)

),

New Column( "DIAMETER",

Numeric,

"Continuous",

Format( "Best", 12 ),

Set Values(

[3, 0.00269979606326021, 6, 0.293126882526161, 4.35739841666667,

3.99839277062575, 4.71640406270759, 0.207693678143616, 4.31985041666667,

4.06547864953982, 4.57422218379352, 0.293126882526161, 0.7429045, 0,

1.48865418833487, 0.207693678143616, 0.5263815, 0, 1.0547789448536]

)

),

New Column( "Phase",

Character,

"Nominal",

Set Values(

{"", "", "", "1", "1", "1", "1", "2", "2", "2", "2", "1", "1", "1", "1",

"2", "2", "2", "2"}

)

)

)

 

tonya_mauldin0

Joined:

Jan 21, 2015

Yes, you can do this.  If you want JMP to calculate the control limits for you, assign the column "type" to the phase role in the control chart.

If you want to assign specific control limits to A and specific control limits to B, then you would still use the phase role in the chart creation, but you would also use Get Limits and a limits data table.  This process is outlined in the following blog post:  http://blogs.sas.com/content/jmp/2016/11/14/using-fixedbaseline-historical-control-limits-in-control...