How does S7-1200 determine program changes through programming?

Introduction to recipe related instructions

The recipe function mainly uses four instructions. READ_DBL and WRIT_DBL are used to read and write recipe data blocks. RecipeExport and RecipeImport are used to convert between recipe data blocks and CSV files. The following describes the use of these four instructions.

READ_DBL

The purpose of the instruction is to transfer the value of the load memory part of the data block variable to the working memory part of the data block variable, as shown in Figure 1.

Typically used in recipes to read recipe data that is stored only in load memory into the active recipe.

Figure 1 READ_DBL and WRIT_DBL principles

Table 1 Parameter list

Take the example program for quick introduction to recipe function as an example

Figure 2 READ_DBL application

As shown in Figure 2, the actual parameter of SRCBLK is "DB1_Cake Recipe".Static_1["DB3_Operation".Index], where "DB1_Cake Recipe".Static_1 is an array of UDT type (cake recipe), and with the following ["DB3_Operation".Index], it becomes an element in the array, that is, "DB1_Cake Recipe".Static_1["DB3_Operation".Index] is a UDT type (cake recipe).

The actual parameter of DSTBLK is "DB2_Activity Recipe". "DB2_Activity Recipe" is a DB established based on the UDT type (cake recipe), which means that "DB2_Activity Recipe" can be regarded as a UDT type.

The actual parameters of SRCBLK and DSTBLK are both of UDT type. You can use the READ_DBL instruction to read "DB1_cake recipe".Static_1["DB3_operation".Index], which is a group in the recipe, into the active recipe.

WRIT_DBL

The purpose of the instruction is to write the working memory part of the data block variable to the load memory part of the data block variable, as shown in Figure 1.

Typically used in recipes to write the active recipe to recipe data stored only in load memory.

Table 2 Parameter list

Take the example program for quick introduction to recipe function as an example

Figure 3 WRIT_DBL application

As shown in Figure 3, the actual parameter of SRCBLK is "DB2_Activity Recipe". "DB2_Activity Recipe" is a DB established based on the UDT type (cake recipe), which means that "DB2_Activity Recipe" can be regarded as a UDT type.

The actual parameter of DSTBLK is "DB1_Cake Recipe".Static_1["DB3_Operation".Index], where "DB1_Cake Recipe".Static_1 is an array of UDT type (cake recipe), and with the following ["DB3_Operation".Index], it becomes an element in the array, that is to say, "DB1_Cake Recipe".Static_1["DB3_Operation".Index] is a UDT type (cake recipe).

The actual parameters of SRCBLK and DSTBLK are both of UDT type. You can use the WRIT_DBL instruction to write the active recipe to "DB1_Cake Recipe".Static_1["DB3_Operation".Index], which is a group in the recipe.

RecipeExport

The purpose of the instruction is to export the recipe data (UDT array) stored only in the working memory into a .csv file for easy editing in the EXCEL or ASCII editor on the computer.

Table 3 Parameter list

Take the example program for quick introduction to recipe function as an example

Figure 4 RecipeExport application

"DB1_Cake Recipe".Static_1 is an array of UDT type (cake recipe), which generates DB1_Cake Recipe.csv file after export.

RecipeImport

The purpose of the instruction is to import the .csv file edited by EXCEL or ASCII editor on the computer into recipe data (UDT array) stored only in the working memory.

Table 4 Parameter list

Take the example program for quick introduction to recipe function as an example

Figure 5 RecipeImport application

After importing the DB1_cake recipe.csv file, you need to overwrite the value of the array of UDT type (cake recipe) "DB1_cake recipe".Static_1.