TCP/PLC server directly accepts TCP connection from the external client. The external software (client) communicates with the server over TCP-IP using a set of specified commands (API). In contrast to the Modbus server – TCP/PLC server has a much looser integration: client can send a “start measurement” command and measurements will continue until stopped. Typically, measurements are done and results are send as fast as possible. There is a properties file that allows to configure the time between the measurement and different adaptive filtering options. Results can be send in analog form (via DAC) to a PLC receiver or in digital form to a TCP data server. In both case, a data streaming interface allows fastest measurement rate. The main drawback of the TCP/PLC server is that exact timing of the measurements cannot be controlled. The main advantage is the fast rate of measurement. This integration option geared toward continuous measurement, where control and timing of individual measurements is not required. TCP/PLC server has three main processes: Measurement, Calculation (Data analysis) and, finally, a Data sender. These processes are loosely integrated and exchange data through the buffers. The processes are monitored to prevent overflow of the buffers. If measurement data buffer starts to grow and the calculation process cannot catch up – measurement speed is throttled. TCP server configured with analog output to PLC TCP server configured with output to the TCP data server
