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M. A. Sibley Consulting – All Rights Reserved MTB 06 – Advanced Minitab Macros 1

MTB – 06 Advanced Minitab®

Macros

This module will cover:• Creating tables of statistics – worked example which includes:

– Creating and saving a series of similar graphs (eg. For each production line)

– How to reference specific rows

– Using constants to fine tune graphs, add date sub-titles, etc.

– Creating a text report & HTML report

• Creating a control charting macro with dynamic stages which demonstrates:

– Reading Excel® files via ODBC

• Looping through subsets

• Adding statistics to each row of a dataset

• Using Excel®’s indirect addressing capability to better access difficulty formatted files

• How to save worksheets as CSV files (readable by Excel®) or as Web Pages

• Avoiding errors which will stop autojob execution; Handling no data “subsets”

• Reference macro code to handle many macro programming situations

• Adding a different “reference” line to each panel of a graph (for a graph using a BY variable).


Prerequisites

Before you tackle this module you

should:

– Know how to create, save and execute

Minitab® macros

– Have set up your PC for Minitab® macro

execution


Using a Table of

Statistics to Create

Multiple Graphs, etc.


Creating a Table of Statistics

Creating a table of Summary Statistics is Minitab ®’s

version of Excel®’s Pivot Table – albeit in a non-

interactive form.

Let’s start by opening a CSV file containing the same

Wind Turbine output data we used in module 2. Using

File > Open we open:

WindByStation.csv

We start capturing the code in a macro.

Creating a Table of Statistics –

cont’d

As in Module 2 we combine the Date and Time columns to create a

Date/Time column using Calc > Calculator. We capture the code

from the session window and add it in to the macro. We add in the

command to change the format of the date to International Date

format. M. A. Sibley Consulting – All Rights Reserved MTB 06 – Advanced Minitab Macros 5

My plain text editor – EditPadPro® adds in the colour coding.


cont’d

In the worksheet I add an asterisk – missing data

symbol – to the first row of column 12. Why? The table

of statistics in the next step will be created after the

last column in use. By putting the missing data

symbol in Column 12 we leave some blank columns in

case we want to have some more “full length” columns

created. I like to have the worksheet organized so

that the full length columns are not interspersed with

the shorter summary statistics columns.



cont’d

• We now

create a

table of

Basic

Statistics:



cont’d

• We capture the code from the Minitab session

window:

• And then we “pretty it up”:

• We paste it back into Minitab’s command line editor

window (accessed via Ctrl/L) and execute the

revised commands.M. A. Sibley Consulting – All Rights Reserved MTB 06 – Advanced Minitab Macros 8


cont’d

• Using techniques from Module 2, we

create a customized graph for one of

the generating stations.



cont’d

Additional

customizations:

• Change Y

Axis Title

• Removed X

axis title

• Added:

– Sub title

– Reference

line

– Grid lines

• Changed title



cont’d

• While the graph

has focus, we

capture the code

to generate the

graph (Editor > Copy

Command Language)

and paste it into

the macro:



cont’d

The next

steps here

are

programming

– not just

capturing

commands

from the

command

window!


K10 is the number of rows in the table of summary statistics – i.e. how many generating stations there are.

Minitab has a limitation on how long strings can be (80 characters) so I use 3 successive change directory commands to move to the folder that will store the JPEG’s generated by the graphing routine.


cont’d


We use a DO loop to create a graph for each station – i.e. each station listed in the table of statistics.

Adding the suffix of [k11] is Minitab’s way of accessing a single row of a column – in this case the k11th

column.

The constant k12 will contain the name of the generating station.

We want plot roughly the last 2 months of data so we add this clause to the Where statement.

This clause will select one

generating station


cont’d


The concatenate function allows us to create a text string constant that we can use as a title for the graph.

The now() function returns the current date time value in internal (numeric) format.

The date session command converts the number into a date/time value using the specified format.

The text command changes the date/time value to the

corresponding text string. This will allow it to become part of a text

string used as a sub-title. The next line creates the string from static text plus this just created value. The erase command gets rid of

data in the column.


cont’d


We store the average output for the station (all rows) in constant k17

We further customize the code for the Plot command by changing the Where command to use the previously created constant.

We use the previously created constant to create the title which includes the name of the station.

We change the reference command to use the value for the “current” station.

We use the previously created constant to create the sub-title which includes the last updated date/time.

We change the NoXFootnote line to end with a semi-colon and then add the sub-commands to We end the DO loop

and the Macro


cont’d

After the

Macro

runs, we

have

created

a JPEG

graph

for each

station:


If the data file were to get updated (say automatically) re-running the macro would overwrite the graphs ,

creating an updated graph.


cont’d

We can extend this macro further to:

– Add additional information to the table of statistics

– i.e. things that are not available with Calc >

Calculator.

– Create a text report saved in plain text and HTML

format



Control Charts with

“Dynamic” Stages

Control Chart Stages

This question posted to my blog looked like a

“teachable moment” so here goes…

My other question is for control charts and creating a stage gate. I know how to hard

code these values in but because I’m only working with a certain time frame, dates can

cause the code to stop running when they are no longer part of the dataset. Is there a

way to run through a date range, see if it is in the dataset, then use that date, if not

move on? I can’t seem to find a good way to make the code ‘move on’ from errors.

Here is the code I’m working with:

XbarChart 'OffsetCalc' 'Min Result Date';

Stamp 'Min Result Date';

Title “X-bar Chart for Offset”;

SubTitle “Splitter 2392”;

Include;

Where &

“'SPLITTER_EQ' =””2392” And 'Min Result Date' > TODAY() – ELAPSED(30)”;

HProcess 'Min Result Date';

Values “2/24/16” “3/6/2016” “3/13/2016”.


Approach

• I created

some

sample data

and saved

them in

excel files:


Hidden rows

Macro to Create Control Chart

This macro has some basic steps:

– Data for the control chart is read into MTB

– Data from the excel file with stage dates is read

into Minitab

– The “out of range” stage dates are set to missing

– A new column of stage dates with no missing

values is created

– The control chart is created

Note: The case of no “in range” stage dates is

handled because if you ask for stage dates that

are out of range, the macro stops with an error –

the original problem!M. A. Sibley Consulting – All Rights Reserved MTB 06 – Advanced Minitab Macros 21

The macro


My fancy plain text editor

(EditPad Pro) highlights the text in various

colours for readability. Much nicer

than Notepad!

See discussion next slide about this code!

Aside: Limitations of

Excel ODBC driver• It would be helpful to read in the last N days of data by adding

an appropriate where clause to the excel ODBC command.

I’ve not found the right syntax to do this. Can anyone help?

• For instance this works:ODBC;

Connect "DSN=Excel Files;DBQ=C:\Users\marka\OneDrive\Documents\MASibley Con" &

"sulting\Web Site\Control chart stages\MyControlChartData.xlsx;DefaultDir=C" &

":\Users\marka\OneDrive\Documents\MASibley Consulting\Web Site\Control char" &

"t stages;DriverId=1046;MaxBufferSize=2048;PageTimeout=5;";

SQLString "SELECT `MyDate`,`MyVar` FROM `Sheet1$` where `MyDate`<{fn CURDA" &

"TE}".

• But this does not:ODBC;

Connect "DSN=Excel Files;DBQ=C:\Users\marka\OneDrive\Documents\MASibley Con" &

"sulting\Web Site\Control chart stages\MyControlChartData.xlsx;DefaultDir=C" &

":\Users\marka\OneDrive\Documents\MASibley Consulting\Web Site\Control char" &

"t stages;DriverId=1046;MaxBufferSize=2048;PageTimeout=5;";

SQLString "SELECT `MyDate`,`MyVar` FROM `Sheet1$` where `MyDate`>{fn CURDA" &

"TE}-99".


The macro – cont’d


ODBC Command to read in the MyStageDates column from the Excel

file: Stages.xlsx

This code handles the case where all dates in the Stages.xlsx file are

not in range for inclusion in the control

chart. The sum of dates will be greater

than zero if any of the dates is non missing.



This code sorts the out of range dates which have been set to missing to the bottom rows of the column. It then uses a DO loop to copy only non-missing rows into a new variable. It then formats the column back to date time and erases the original – no longer needed – column.

Note: The [k11] subscript is Minitab’s way of allowing you to reference a single cell in the column.



We are only including “in range” dates.

We use the “in range” stage dates column to define the stages for the control chart.

If the remaining portion of the first stage of the graph is short, its label can partially obscure the label for the next stage. This code is what results if you interactively delete this first label.

The code to save the graph as a JPEG file.



This remaining code is for the case where no stage dates are “in range” and so we make sure to comment out the stages related commands so they don’t generate errors and stop the macro.

The resulting Control Chart


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