Bus connection, Performance characteristics, Flexible power management – Festo Контроллер двигателя CMMD-AS User Manual
Page 24: 3 bus connection, 4 performance characteristics
3. Product description
24
Festo P.BE-CMMD-AS-HW-EN 1002NH
3.3
Bus connection
Both axes are controlled over a shared fieldbus interface. If a bus connection is activated,
this control interface always applies for both axes.
With CAN and RS485, the second axis gets the address of the first axis +1
Node number
Slave
= node number
Master
+1
Bus modules (PROFIBUS or DeviceNet) must be plugged into the extension slot [Ext1].
The bus modules are automatically recognised when the controller is switched on.
For PROFIBUS and DeviceNet, only the bus address specified on the DIP switches is
assigned; the data for two controllers are send in a shared telegram.
Note
For DeviceNet and PROFIBUS, the fieldbus data for axis 2 are read
from axis 1, passed on to axis 2 and evaluated there. The answer is
returned to axis 1 with the next communication task (every 1.6 ms)
at the earliest. Only then can the answer be returned over the
fieldbus.
This means that the processing time of the fieldbus protocols –
depending on the fieldbus – can be twice as long as with the
CMMS-AS.
Example:
Processing time for 8 bytes of control data + 8 bytes of parameter
data = 16 bytes of data per axis and data direction.
CMMS-AS
1.6 ms
CMMD-AS
2 x 1.6 ms = 3.2 ms
3.4
Performance characteristics
Flexible power management
The nominal current of both axes together is 8 A. These 8 A can be distributed flexibly
between axes 1 and 2. The maximum nominal current for axis 1 is thereby 7 A.
With a distribution of 7 A : 1 A for axes 1/2, the specified total rated output of the
double output stage in S1 operation must be reduced. An increase in the maximum
nominal current is permissible only for axis 1 due to the cooling profile.
The maximum peak current per axis is 10 A. Unlike the nominal current, a distribution
of the maximum peak current is not possible.
The motor nominal and peak currents are set fixed in the FCT user software.
An increase in the motor nominal current can result in impermissible temperature
rises.