Siemens SIMATIC ET 200S Manual page 583

DP master
A → master that complies with IEC 61784-1:2002 Ed1 CP 3/1 is known as a
DP master.
DP slave
A → slave running on the PROFIBUS on the basis of the PROFIBUS DP protocol
in accordance with IEC 61784-1:2002 Ed1 CP 3/1 is known as a DP slave.
Equipotential bonding
Electrical connection (equipotential bonding conductor) that brings the exposed
conductive parts of electrical equipment and other conductive parts to the same or
approximately the same potential in order to prevent troublesome or dangerous
voltages arising between these parts.
ET 200
The ET 200 distributed I/O system with the PROFIBUS-DP protocol enables
distributed I/O devices to be connected to a CPU or an appropriate DP master. A
feature of the ET 200 is its fast response times, since only a small amount of data
(bytes) is transferred.
The ET 200 is based on IEC 61784-1:2002 Ed1 CP 3/1.
The ET 200 works on the master/slave principle. Examples of DP masters are the
IM308-C master interface or the CPU 315-2 DP.
DP slaves can be the distributed I/O devices ET 200M, ET 200X, ET 200L,
or ET 200S or DP slaves from Siemens or other vendors.
FREEZE
This is a control command of the DP master to a group of DP slaves.
When a DP slave receives the FREEZE control command, it freezes the current
status of the inputs and transfers them cyclically to the DP master.
After each subsequent FREEZE control command, the DP slave freezes the status
of the inputs again.
The input data is not transferred from the DP slave to the DP master again
cyclically until the DP master sends the UNFREEZE control command.
Ground
The conductive mass of earth, the electrical potential of which is equivalent to
zero. In the vicinity of grounding electrodes, the potential may not be zero. The
term "reference ground" is often used here.
ET 200S Distributed I/O System
EWA-4NEB 780602402-12
Glossary
Glossary-3