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Entry type: FAQ Entry ID: 18410633, Entry date: 02/12/2004

Technology CPUs: Determining a Technology Parameter Number

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How do you determine a technology parameter number that is required in order to write with the FB407 "MC_WriteParameter" parameter or read with the FB406 "MC_ReadSysParameter" parameter?

FB 407 "MC_WriteParameter" can be used to change parameters in technology objects, that have been configured with S7T Config, while the technology CPU is running. This FB changes the preconfigured technology parameters of axes, such as the velocity or acceleration during the axis runtime.

FB 406 "MC_ReadSysParameter" supplies selected parameters of a technology object (e.g. axis or cam).
There is a parameter number with corresponding value range for each parameter.

Fig. 1: Required parameter number

Open the instance DB for FB407 to determine the number for each parameter in the DB parameterization. You must open the instance DB in the Parameter view. In the "Technology Object" box, select the object for which the parameter is required, and look for the parameter in the "Parameter list" (Fig. 2).
The parameter number you are looking for is then displayed in the "Number:" box.

Fig. 2: Determined parameter number

As Fig. 2 shows, the parameter number for acceleration is "4141". The acceleration can be changed by calling FB 407 "MC_WriteParameter" and entering the parameter number 4141.

Alternatively, you can also find the number for the requisite technology parameter in the manual "S7 Technology", section 9.4 Technology Parameters in Entry ID: 30119663.

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