Software in Compass DCS can be divided into 3 layers as shown in Figure 1. At the bottom level there is JCOP-FW (refer to JCOP-Framework documentation) which contains the most common components and devices used in a DCSs of the four LHC experiments. It also provides a ready connection to these equipment either via OPC or DIM
At the top of the JCOP-FW is implemented some additional devices (refer to document of Additional JCOP-Framework components) which contains e.g. an logical element for grouping devices together and customized panels and scripts.
On the highest level are all scripts and panels developed by Compass DCS developers. This document describes only the panels and scripts made at this level.
Figure 1: Software layers
PVSS is a project based system. This means that all data required for a project are stored in a directory, the project directory. This allows you to have other projects in addition to the main project, which in Compass DCS is named as "compass_dcs". The data are always read from the main project directory first. If a file is not found, the program looks in the path of the next higher project. In a the system this project hierarchy feature has been used when the Frameworks (basic- and additional devices) have been integrated into a main project. Both frameworks has their own project directory (.../comp_fw/ and .../jcop_fw/) which contains all the files (panels, scripts, etc.) of the framework.
Advantage of such a hierarchy is when modifying e.g. a panel part of a framework, the new saved version will be saved under the main project (.../compassdcs/panels), while the original version stays unchanged.
