The data to be acquired from the SIMATIC S7?300/S7?400 is selected by configuring the ION SIMATIC S7 PN function block in the SIMATIC S7.

The function block is initialized in the startup OB of the PLC (OB100, OB101, OB102). During initialization, the number of active channels is determined, the cycle time imported, and further calculations made for operation. The channels are filled with data in the program of the SIMATIC S7?300/S7?400.

The function block is then executed passively in the program. Data exchange with the analysis software on the industrial PC only starts after being called in a time interrupt OB (e.g. OB35) by SIPLUS CMS4000 X-Tools. The data is visualized, analyzed and archived there.

The signals are collected in two buffers for transmission and then sent to SIPLUS CMS4000 X?Tools with relative time stamps. Each buffer can accommodate 712 bytes. With 178 active channels, one buffer serves as a send buffer and the current values are written in the other one. The buffers are read and sent alternately.

If not all of the channels are activated, multiple cycles can be buffered: With 89 channels, a buffer can save two cycles, and a send job is therefore only initiated after two cycles. The communication load is thus reduced.

From the point of view of SIPLUS CMS4000 X?Tools, the ION SIMATIC S7?400 T001 is the Ethernet device that communicates by means of UDP/IP.