NORD Drivesystems BU0270 - Manual (Page 35)

5 EtherCAT - Data transfer
BU 0270 GB Subject to technical amendments 35
5.2 Process data (PDO communication)
The process data is transmitted via PDOs These are fixed and cannot be changed.
Control words and setpoints are transferred from the bus master to the SK TU4-ECT as process data and in
return, the status word and actual values from the SK TU4-ECT are sent to the bus master from the FI. This
transfer is carried out cyclically and the master can access these process values directly, as they are stored in
the I/O area.
Via the SK TU4-ECT, up to 4 FIs and the SK TU4-ECT itself can be accessed, whereby in the basic setting,
only one SK 200E frequency inverter is integrated. This prevents unnecessary data from being transported in
the telegram, which would increase the bus load.
The process data structure for an individual FI contains 8 Bytes of inverter data.
Direction of transmission Transmitted data (8 Byte)
1st word 2nd word 3rd word 4th word
Transmission to SK TU4-ECT Control word Setpoint 1 Setpoint 2 Setpoint 3
Reception from the SK TU4-ECT Status word Actual value 1 Actual value 2 Actual value 3
The process data structure for the bus module includes 2 Bytes, of which only the Low Byte is used.
Transmitted data (2 Byte)
Direction of transmission
Low byte High byte
Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 … Bit 15
Transmission to SK TU4-ECT DOut1 DOut2 - - - - - - Not used
Reception from the SK TU4-ECT DIN1 DIN2 DIN3 DIN4 DIN5 DIN6 DIN7 DIN8 Not used
In the minimal configuration 8 Bytes of process data are sent in a single telegram (control of exactly one
frequency inverter). In the maximum configuration there are 34 Bytes (I/Os of the bus module (2 Bytes) + 4
frequency inverters (4 x 8 Bytes)).
The assignment of values in the setpoint/actual value area is carried out:
in the SK 200E via the parameters P543 [-01 … -03] and P546 [-01 … -03],
in the SK 500E via the parameters P543 to P548.
Structure of the process data telegram from the SK TU4-ECT for an FI