Description readmee

README.md

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 # @simatic-ax.lacyccom
 
 ## Description
+The following section shows a scenario for a possible application of the LAcycCom
+library:
+
+With acyclic data exchange, contrary to cyclic communication, data transfer takes 
+place when an explicit request is made, e.g. in order to read and write drive object 
+parameters. Acyclic parameter access occurs parallel to the cyclic process data 
+exchange. This saves resources, since the data is only requested on demand, i. e. 
+when a parameter has to be transferred.
+The "Read data record" and "Write data record" services are available for acyclic 
+data exchange.
+According to the PROFIdrive profile, for drives in conformance with PROFIdrive, 
+only one DPV1 (asynchronous PROFIBUS communication) request is permissible 
+for each drive object and control unit for non-cyclic (acyclic) communication 
+(parameter requests). If two or more DPV1 requests are simultaneously issued to a 
+drive unit, conflicts can occur when processing the request in the drive unit. These 
+conflicts then cause the different DPV1 requests to mutually interfere with one 
+another. In order to prevent that such bus conflict occurs, it is the user’s
+responsibility to avoid that and a check must be made for each new DPV1 request 
+whether another request is already active on the drive object involved. This is 
+certainly the case if system functions are also used that are not exclusively 
+intended to communicate to drive units via DPV1 services.
+In order to relieve the user of this task a request management called Resource 
+Manager exists that handles the management of DPV1 services for the user. This 
+function is presented here. However, the introduction of this request management 
+assumes as prerequisite that each function, which utilizes DPV1 services, will also 
+actually use them.
+
 
 ## Install this package