1. Introduction#

The main goal of the “committee for the standardization of sample environment communication” is to establish a common standard protocol SECoP for interfacing sample environment equipment to experiment control software.

Definition: Experiment Control Software (ECS)

Software controlling the hardware for carrying out an experiment. Includes the user interface. Usually speaks several protocols with different parts of the instrument. Often also called “instrument control” in short.

There is a task (7.1) within the European framework SINE2020 also dealing with this subject. In its description we read:

… The standard should be defined in a way that it is compatible with a broad variety of soft- and hardware operated at the different large scale facilities. … The adoption of this standard will greatly facilitate the installation of new equipment and the share of equipment between the facilities. …

This also covers the aims of the committee.

The idea is that a sample environment apparatus can easily be moved between facilities and instruments/beamlines. As long as the facilities have implemented a SECoP client within its ECS, and on the apparatus a SECoP server is implemented, using the apparatus for an experiment should be straightforward. An ECS can be built in such a way that the configuration of the apparatus may be as short as entering a network address, as the description can be loaded over the protocol.

Definition: Sample Environment Control Node (SEC node)

Computing unit or process, connected to all control units (temperature controller, flow controller, pressure sensor …) of a sample environment, bridge to the ECS. SECoP specifies how ECS speak with a SEC node. The SEC node allows ECS to access a set of modules (and their parameters/commands) via SECoP. It also provides a list of accessible modules and parameters as well as descriptive meta data.

1.1. Other requirements#

  • The protocol should be easy to use.

  • It should be easy to implement in connection with existing ECSs and sample environment control software.

  • It should be possible to be implemented on the most common platforms (operating systems and programming languages).

  • The protocol should be defined in way that allows a maximum compatibility: Newer and older versions of the syntax should be compatible.

  • The protocol should be defined in a way that allows maximum flexibility: A simple (= with minimal features) ECS implementation should be able to communicate with a complex SEC node (with a lot of features), and an ECS with a rich number of features should be able to cope with a simple SEC node, implementing only a minimum number of features/functionality.