ifm
Basic Device Manual AS-i ControllerE M4 Target V15
2015-10-30
Terms and abbreviations
Hardware error, exception error
276
SELV
SELV =
S
afety
E
xtra
L
ow
V
oltage
Active parts integrated in SELV circuits must not be connected to ground or
protective conductors 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 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
have a clearly defined and unique
→address in the bus. A distinction is made
between:
Single slaves whose address
number may only be present once on the master and A/B slaves with an A or
B being appended to the address number and which may therefore be
present twice.
Target
The target indicates the target system where 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 a cycle. The following process happens:
PLC cycle: The PLC program performs one complete run.
AS-i cycle: all AS-i slaves are updated (5...10 ms).
