PreStep and SequenceCall

[Sunny]

Hi,

i use a standard Sequence Call with an expression to create path and filename within a custom steptype.

The expression contains two field variables of this customized steptype.

The idea was to use a PreStep to fill in valid values to these two fields and the Sequence Call would then be running by evaluating the entire expression.

Unfortunatly TestStand is evaluating the expression specified for the Sequence Call  before calling the PreStep.

This is not the expected operational behaviour!

Could anyone give me a hint how to avoid evaluation of an expression used to generate a dynamic  sequence file path before executing the defined PreStep?

[RayFarmer]

Hi,

Actually, that is the correct sequence, see table3-4 of the TestStand Reference Manual Chapter3-12, Action 11 is evaluate Pre-Expression and Action 12 is call the PreStep substeps for steptype.

You could use the FindFile function to return the path of the sequence file.

Regards

Ray Farmer

[Sunny]

Hi Ray,

i think the specified order is comprehensible, but in the described case the expression to evaluate is not part of any specified Pre-Expression but is used as value for the 'File Path or Reference' field in 'Edit Sequence Call' window of this customized Steptype. I would expect that this expression is evaluated in Action 13 (Call Module).

Please explain where the 'FindFile' function could be used to solve my problem!

Regards,

Sunny

[RayFarmer]

Hi Sunny,

Is it possible to provide an example of your Steptype, code and sequence file?

Regards

Ray Farmer

[Sunny]

Hi Ray,

attached a ZIP file with the configuration data of the steptye and the LabVIEW code for the PreStep. In original there is also provided an edit step for this steptype, within this edit substep the value for the second variable would be set.

See the default values for the two variables in the expression for Sequence Filepath for this steptype. These values are used by TestStand to look for a sequence file which will never be called, since the value of the variable Step.MobileType will be changed by the PreStep.

Filepath or Reference:                 Step.MobileType &"\\"& "Feature_" + Step.Feature + ".seq"

TestStand searches for:              "template\Feature_Template.seq"

Execution will run:                        "Siemens_S65\Feature_Template.seq"

Kind regards,

Sunny

[Sunny]

Here is the attachment!

[Sunny]

Hi Ray,

i still have the described problem. Could you readjust the described operational behaviour of TestStand with my attachment?

Kind regards,

Sunny

[RayFarmer]

Hi Sunny,

Sorry, been a bit busy. I will look at at it this evening.

Regards

Ray Farmer

[Erik_Crank]

The sequence call step does load its module before executing the PreStep. However, the sequence call step will reload the module before it executes if the value of the module sequence file expression changes after executing the PreStep. In your case, as long as you have a valid sequence file "template\Feature_Template.seq", your system should work. This sequence file can be empty.

[RayFarmer]

Hi Sunny,

I agree with crankster, therefore in your example, provide there is a sequencefile called "Feature_Template.seq" in the path "..\Siemens_S65\Template\", the sequencefile "Feature_Template.seq" will be invoked and executed.

Regards

Ray Farmer