turck BL20-GW-CANOPEN, User Manual, Page: 91 / 95

D301087 1211 - BL20 CANopen
9-5
Polling
Establish a Polled I/O Connection, i. e. a conventional Master/Slave relationship between a controller and a
DeviceNet device.
Potential compensation
The alignment of electrical levels of electrical components and external conductive components by means of an
electrical connection.
Potential free
Galvanic isolation of the reference potentials in I/O modules of the control and load circuits.
Potential linked
Electrical connection of the reference potentials in I/O modules of the control and load circuits.
Protective earth
Electrical conductor for protection against dangerous shock currents. Generally represented by PE (protective
earth).
Radiation coupling
A radiation coupling appears when an electromagnetic wave hits a conductive structure. Voltages and currents
are induced by the collision. Typical sources of interference are e. g. sparking gaps (spark plugs, commutators
from electric motors) and transmitters (e. g., radio), that are operated near to conducting structures.
Reaction time
The time required in a bus system between a reading operation being sent and the receipt of an answer. It is the
time required by an input module to change a signal at its input until the signal is sent to the bus system.
SDO
see chapter 3 Short description of CANopen (Seite 3-1) .
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