ADS Communication

ADS based on client-server principle. An ADS query calls the corresponding indication methods on the server side. The ADS response calls the corresponding confirmation method on the client side.

ADS Communication 1:

ADS client-server sequence

In this section both the outgoing and incoming ADS communication is described for TwinCAT 3 C++ modules.

ADS instruction set

Description

AdsReadDeviceInfo

The general device information can be read with this command.

AdsRead

ADS read command for retrieving data from an ADS device.

AdsWrite

ADS write command for transferring data to an ADS device.

AdsReadState

ADS command to query the state of an ADS device.

AdsWriteControl

ADS control command to change the state of an ADS device.

AdsAddDeviceNotification

Observe variable. The client is informed in case of an event.

AdsDelDeviceNotification

Removes the variable that was previously linked.

AdsDeviceNotification

Used to transfer the device notification event.

AdsReadWrite

ADS read/write command. Data is transmitted to an ADS device (write) and its response data read with one call.

The ADS Return Codes apply to the entire ADS communication.

As an introduction, look at Sample07: Receiving ADS Notifications.