Instructions:
Evaluating the "ACK button" on touch operator panels:
 

No.	Procedure
1	You cannot assign any fixed function to the "ACK button" on touch operator panels. In order to determine whether the ACK button has been activated on a touch operator panel you must evaluate the variable for the "Read Acknowledge Variable" area pointer via the controller. If an operator acknowledges a bit message, then a specific bit is set in the variable for the "Read Acknowledge Variable" area pointer. This change in the variable is evaluated by the "Exclusive OR word" operation. Via this evaluation you can then trigger other functions such as an error alarm acknowledgment via the controller, for example. Fig. 01
2	Sample program Task: The ACK button is to used for acknowledging error messages via the controller. There are several touch operator panels on which the identical error message is displayed in the event of an error. It should be possible to acknowledge all error messages at once on any one of these operator panels. Program contents: The program contains the S7 controller program and an MP370 Touch and a TP270 Touch configuration. If one or more messages are triggered and subsequently the ACK button on one of the operator panels is pressed, then the error messages are acknowledge at the same time on both operator panels (MP370/TP270) via the controller program. You can change the program at will to meet your specific requirements. Evaluation of the ACK button always follows the same pattern (evaluation of the acknowledge bit). The sample program attached contains the evaluation of a total of 48 error messages. Fig. 02

Sample program:
The attached download contains the archived STEP 7 project with the functions described above. You can change the project to suit your requirements.

  Attachment 1: Ack_quit.exe ( 2353 KB )  

Runnability and test environment:
The example can be used on all the CPU types of SIMATIC S7-300 and S7-400.
The following table lists the components that have been used to create this entry and verify the functions described.
 

Component	Product and version
PC operating system	Microsoft Windows XP V5.1 SP1
Standard Tools	STEP 7 V5.3 SP1
Engineering Tools	-
HMI Software	WinCC flexible 2004 SP1
HMI devices	1. MP370 Touch 2. TP270 Touch
Controllers	S7 CPU 316-2DP

Table 1: Creation environment of the download attached