Overview

The library contains function blocks for acyclic client-server communication between a BC9xxx Bus Controller and other ADS devices in the network. The way in which these function blocks operate is not significantly different from that for the PLC runtime system on the PC. 

Requirements

The upper 4 digits of the AMS NetID (network address) and the TCP/IP address of the ADS target device must be in agreement if the IP connection is to be established. 

Example:

ADS communication is to be established with an FC310x Profibus card. The card is assigned its own network address during configuration by the TwinCAT System Manager, e.g.: '172.16.2.209.4.1'. This means that it can be considered as an independent ADS device (a remote PC). In order that the IP connection can be established, the first four figures of the network address must agree with the TCP/IP address of the PC in which this card has been configured. This means that the TCP/IP address of the PC must be '172.16.2.209'.

Comments

• The number of connections that may be open simultaneously is restricted to four, in order to maintain the use of resources at a minimum. 
• A connection is established automatically when an ADS command is sent.
• A connection is automatically closed after approx. 10 seconds if it has not been used during this time. An unneeded connection can be explicitly closed with the ADSCLOSE function block before this time has elapsed.
• The maximum data size that a BC9xxx Bus Controller can send ( e.g. with ADSWRITE or ADSREADRESBC ) and receive ( e.g. with ADSREAD or ADSWRITEIND ) is limited to 1980 bytes.

ADS function blocks