Lenze ETC Motion Control - Manual (Page 199)

Machine constants
Software configuration
MK_DELTAT
4
4.3
4.3.18
l
199 EDSTCXN EN 2.0
4.3.18 MK_DELTAT
This machine constant sets the internal interpolation cycle [ms] of the
control. During each of these rough interpolation cycles, the control
calculates new position values for the participating axes from the
programmed path. The smaller the cycle, the closer are the calculated
positions to one another. However, this also means that the calculation load
for the control and the bus load for the drive amplifier with digital interface
is higher. The ETC can operate with a minimum rough interpolation cycle of
1 ms.
If the amplifiers are provided with a CAN interface, the limited bandwidth of
the CAN bus transfer is extremely important. In the following table, you can
find the minimum rough interpolation cycle and the average CAN2 bus load
depending on the number of configured CAN axes and the set bit rate.
For the calculation of the bus load, only the cyclic telegrams were taken into
account, while any additional asynchronous telegrams from ETC−MMI or PLC
were not. The specified value may vary slightly due to different telegram
lengths for different drive amplifiers.
Number of axes 1000 kBit 500 kBit 250 kBit
1 1 ms / 29 % 2 ms / 29 % 3 ms / 38 %
2 1 ms / 52 % 2 ms / 52 % 4 ms / 52 %
3 2 ms / 38 % 3 ms / 50 % 5 ms / 60 %
4 2 ms / 49 % 3 ms / 66 % 6 ms / 66 %
5 2 ms / 61 % 4 ms / 61 % 7 ms / 70 %
6 2 ms / 73 % 4 ms / 73 % 8 ms / 73 %
7 3 ms / 56 % 5 ms / 67 % 9 ms / 75 %
8 3 ms / 64 % 5 ms / 77 % 10 ms / 77 %
9 3 ms / 72 % 6 ms / 72 % 11 ms / 78 %
10 3 ms / 79 % 6 ms / 79 % 12 ms / 79 %
11 4 ms / 65 % 7 ms / 75 % 13 ms / 80 %
12 4 ms / 71 % 7 ms / 81 % 14 ms / 82 %
Once it has been established that no asynchronous telegrams are
transferred by MMI or PLC during operation, the use of the available transfer
bandwidth can be optimized, see the following table (no guarantee):
Number of axes 1000 kBit 500 kBit 250 kBit
1 1 ms / 29 % 1 ms / 57 % 2 ms / 57 %
2 1 ms / 52 % 2 ms / 52 % 3 ms / 69 %
3 1 ms / 75 % 2 ms / 75 % 4 ms / 75 %
4 2 ms / 49 % 3 ms / 66 % 5 ms / 79 %
5 2 ms / 61 % 3 ms / 81 % 6 ms / 81 %
6 2 ms / 73 % 4 ms / 73 % 7 ms / 83 %
7 2 ms / 84 % 4 ms / 84 % 8 ms / 84 %
8 2 ms / 96 % 4 ms / 96 % 8 ms / 96 %
9 3 ms / 72 % 5 ms / 86 % 9 ms / 96 %
10 3 ms / 79 % 5 ms / 95 % 10 ms / 95 %
11 3 ms / 87 % 6 ms / 87 % 11 ms / 95 %
12 3 ms / 95 % 6 ms / 95 % 12 ms / 95 %