DCS is reading values from two Schneder PLCs used for Gas systems of various detectors. These PLCs has a stand-alone program inside and therefore there is no need for controlling (writing data). These devices are read via Profibus and connection to PVSS is made by using OPC Server-Client procedure.
Hodoscope group is using two I/O slave modules containing set of analogue and digital inputs and outputs. The purpose of these modules is to control the movement of Hodoscopes for a more precise trigger. Modules are read as well via Profibus fieldbus and PVSS OPC Client connected to OPC server for the fieldbus is used to receive the data into PVSS database.
Several ELMBs are used for different purposes, but mostly for temperature measurements and for controlling the Low Voltage system of MWPC group. In addition to this a few status signals are read using ELMBs. ELMBs are connected to CAN fieldbus read by OPC server.
This Windows NT PC is used as front-end computer for all the equipment controlled via OPC Server-Client mechanism. PVSS has been installed into this PC for being able to run OPC managers (Clients) which makes the connection to PVSS database running in back-end computer (pccompass04, main Linux system). In is described the connection between OPC managers, event manager and data manager.
When PVSS project called `compass_opc', located in d:\compassboot\compass_opc, will be started three OPC managers makes a connection to three OPC servers respectively:
For being able to start/stop OPC managers one has to be logged in as administrator with a password ******. Note that PVSS system has to run in pccompass04 before the OPC managers will be able to make a connection to data and event manager.
Figure 1: Interactively between the main project (pccompass04) and OPC -project
