ifm
Supplementary device manual Interface CANopen in the AS-i controllerE
Terms, abbreviations
110
SELV
SELV =
S
afety
E
xtra
L
ow
V
oltage
Active parts of safety extra low voltage circuits must neither be connected to
ground nor to protective wires of other circuits. They must be safely separated
from active parts with higher voltage.
SELV circuit = secondary circuit (output voltage) which is rated and protected so
that its voltages do not exceed a safe value in case of correct operation (of the
power supply) or in case of a single fault (of the power supply):
SELV circuits are separated from the input voltage (mains voltage) by double or
enhanced insulation. The voltage value must not exceed 60 V DC (or 42.4 V
AC).
Single slave
Slave whose address number may only occur once on the
master.
Slave
Passive participant on the bus, only responds on request of the
master. Slaves
in the bus have a unique
address.
There is a difference between:
single slaves whose address numbers may only occur once on the
master and
A/B slaves with an A or B being appended to their address number which may
therefore be present in the
master twice.
Target
The target indicates the target system on which the PLC program is to run. The
target contains the files (drivers) required for programming and parameter
setting.
Unit ID
Modbus
Watchdog
In general the term watchdog is used for a component of a system which
watches the function of other components. If a possible malfunction is detected,
this is either signalled or suitable program branchings are activated. The signal
or the branchings serve as trigger for other co-operating system components
which are to solve the problem.
Cycle time
This is the time for one cycle. The following happens:
PLC cycle: the PLC program performs one complete run.
AS-i cycle: all AS-i slaves are updated (5...10 ms).
