Samson Controls offers Electro
pneumatic positioners which allow
stroke tests to be carried out without
disrupting the process line. For
example, the type 3730-3 positioner
has an ESD (Emergency Shutdown)
function and can be mounted on the
valve in addition to the solenoid
valve, or to replace it.

It enables the valve to be moved
precisely to follow the set point
within the valve’s working ratio. The
partial stroke test is integrated into
the positioner to detect a sticking
valve. Test schedules can be as
flexible as required and prolonged if
necessary. Test validation can be
performed simply by using the
corresponding instrumentation and
initiating it over a commonly
available SIS logic solver.