TwinCAT PLC SECS/GEM Library

Beckhoff’s TwinCAT PLC software is widely used in the semiconductor and related industries. With the increasing adoption of the SECS/GEM standard interconnect interface in smart factories, more factories are requiring equipment to communicate with the factory’s EAP/MES system via the SECS/GEM standard communication protocol to achieve automated production run.

Since Beckhoff does not provide SECS/GEM software products, for OEMs using Beckhoff TwinCAT software as the main control, a host computer PC is usually required. An IPC software engineer who is familiar with factory automation then develops the SECS/GEM communication interface using a PC language (C++, C#, etc). This approach has the following disadvantages:

An additional host PC is needed, increasing hardware costs.
Need PC language software development engineers specializing in factory automation.
PLC development engineers cannot freely directly interface with factory EAP/MES; all data, events, and alarms need to be relayed.

To enable TwinCAT PLC development engineers to directly develop SECS/GEM communication interfaces, Kxware team developed SECS/GEM PLC library KXTCGEM Lib for Beckhoff TwinCAT PLCs. No additional hardware or host PC programming is required. The SECS/GEM interface can be quickly implemented directly in the TwinCAT PLC project by calling the communication methods encapsulated in the ST PLC library. The following is an introduction to this library.

1. Supported SEMI standard versions

The SEMI standard versions supported by KXTCGEM are shown in the table below:

2. Add SECS/GEM PLC software library

Run the KXTXGEM installation package on a TwinCAT 3 PLC, the library program supports to run on TwinCAT Windows 7/8/10. The library is installed by default in the directory of C:\TwinCAT\GEM\ . After installation, open the TwinCAT 3 software, create a new PLC project, and right-click on the References section of the PLC project to add the SECS/GEM library file.

3. PLC ST code calls SECS/GEM API

The various methods of the TwinCAT SECS/GEM library are encapsulated in the FB_GEM function block. Users can access and operate on the various interfaces of GEM by defining a global FB_GEM object.