Lenze EMF2191IB - Manual (Page 20)

Technical data
Data for POWERLINK communication
Cycle time
4
l
20 EDSMF2191IB EN 2.0
4.3.1 Cycle time
The cycle time of the communication system is the time in which all process data between
the master (managing node) and the slaves (controlled nodes) are exchanged.
It depends on the data of the communication system and can be calculated as follows e. g.
for a baud rate of 500 kbps:
t
zykl
+ 3, 35 @ 10 *3 (n ) 48 ) 3 BK) ) 0, 24 L ) 0, 2
t
cycl
Cycle time [ms]
n Sum of all data bits in the POWERLINK network
BK Number of bus terminals
L Length of the remote bus cable [km]
The following diagram shows the relation between cycle time and number of connected
fieldbus nodes. The given values refer to the connection of Lenze inverters (e.g. 82xx) with
48 bits (1 parameter data word + 2 process data words).
12
10
8
6
4
2
10 20 30 40 50 60
Cycle time
[ms]
Number of nodes
1
Fig. 4−1 Relationship between cycle time and number of nodes
4.3.2 Processing time in the inverter
There are no interdependencies between parameter data and process data.
Processing times Parameter data Process data
Processing time inside the
inverter l For controller−internal parameters
approx. 30 ms + a tolerance of 20 ms
l Some codes may have a longer
processing time (see documentation
of the inverter)
l There is no synchronisation between
the communication module and the
inverter.
l Times of 8200 vector/motec,
starttec: Approx 3 ms + a tolerance of
2 ms
l Times of 9300 / ECS: Approx. 2 ms +
a tolerance of 1 ms (each being
independent of the basic cycle time)
Additional times outside
the inverter l Communication transfer times
l Communication processing times of the transmitting node