  The European Spallation Source (ESS) in Lund, Sweden is just entering the
construction phase with 3 neutron instruments having started in its design
concept phase in 2014. As a collaboration of 17 European countries the majority
of hardware devices for neutron instrumentation will be provided in-kind. This
presents numerous technical and organisational challenges for the construction
and the integration of the instruments into the facility wide infrastructure;
notably the EPICS control network with standardised hardware interfaces and the
facilities absolute timing system. Additionally the new generation of pulsed
source requires a new complexity and flexibility of instrumentation to fully
exploit its opportunities. In this contribution we present a strategy for the
modularity of the instrument hardware with well-defined standardized
functionality and control & data interfaces integrating into EPICS and the
facilities timing system. It allows for in-kind contribution of dedicated
modules for each instrument (horizontal approach) as well as of whole
instruments (vertical approach). Key point of the strategy is the time stamping
of all readings from the instruments control electronics extending the event
mode data acquisition from neutron events to all metadata. This gives the
control software the flexibility necessary to adapt the functionality of the
instruments to the demands of each single experiment. We present the advantages
of that approach for operation and diagnostics and discuss additional hardware
requirements necessary.
