S7-300/400 Tip Analog Scaling Tip No. 1

Analog Inputs and Outputs in an S7 PLC are represented in the PLC as a 16-bit integer. Over the nominal span of the analog input or output, the value of this integer will range between ­27648 and +27648. However, it is easier to use the analog values if they are scaled to the same units and ranges as the process being controlled. This applications tip describes methods for scaling analog values to and from engineering units.

The program for scaling analog values consists of 2 function (FC) blocks. These blocks are optimized for unipolar (0..27648) analog values, but will also work with bipolar analogs. Both blocks are shown in two different languages: LAD and STL.

FC100 converts an integer in a nominal 0..27648 range to a floating point number in the specified engineering units.

FC101 converts a floating point number in the specified engineering units to an integer in 0..27648 range.

Copyright 1996 by SIEMENS page 1 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.

S7-300/400 Tip Analog Scaling Tip No. 1

Copyright 1996 by SIEMENS page 2 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.

S7-300/400 Tip Analog Scaling Tip No. 1

Copyright 1996 by SIEMENS page 3 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.

S7-300/400 Tip Analog Scaling Tip No. 1

Copyright 1996 by SIEMENS page 4 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.

S7-300/400 Tip Analog Scaling Tip No. 1

Copyright 1996 by SIEMENS page 5 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.

S7-300/400 Tip Analog Scaling Tip No. 1

Copyright 1996 by SIEMENS page 6 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.

S7-300/400 Tip Analog Scaling Tip No. 1

The SIMATIC S7-300/400 Application Tips are provided to give users of the S7-300 and S7-400 some indication as to how, from the view of programming technique, certain tasks can be solved with this controller. These instructions do not purport to cover all details or variations in equipment, nor do they provide for every possible contingency. Use of the S7-300/400 Application Tips is free.

Siemens reserves the right to make changes in specifications shown herein or make improvements at any time without notice or obligation. It does not relieve the user of responsibility to use sound practices in application, installation, operation, and maintenance of the equipment purchased. Should a conflict arise between the general information contained in this publication, the contents of drawings or supplementary material, or both, the latter shall take precedence.

Siemens is not liable, for whatever legal reason, for damages or personal injury resulting from the use of the application tips.

All rights reserved. Any form of duplication or distribution, including excerpts, is only permitted with express authorization by SIEMENS.

Copyright 1996 by SIEMENS page 7 / 7 Scaling.doc Status: 11/96 Version 1.0

SIMATIC S7-300/400 customers have free use of the application tips. These tips are only a general approach to using the S7-300/400 with various applications. Your specific application may be different. It is your responsibility to use the SIMATIC S7-300/400 properly in your applications.