AUMA SIMA 2, Руководство пользователя

Страница: 18 / 44

must be introduced at the cable entry to the control cabinet housing the SIMA².
Overvoltage protection modules for fieldbus cables are available on request.
5.5. Interface and communication to the actuators via Modbus RTU
The interface between SIMA² and the actuators of the AUMA Group is the open and
internationally standardised Modbus protocol. The physical Modbus RTU connection
between SIMA² and the actuators complies with the EIA-485 standard.
Information
Heed the installation instructions for EIA-485 based fieldbus systems and the correct
implementation of the communication connections for all fieldbus devices.
All connections to the actuators are made via cables without connectors. The EIA-485
interface module utilised a proven system of spring clamp terminals. To this end, the
stripped cable ends are directly inserted into the corresponding spring clamp terminal.
Each interface module corresponds to one Modbus interface.
Figure 16: EIA-485 interface module (extract)
Information
Verify addressing of fieldbus devices!
●
Refrain from assigning twice the Modbus addresses within one network!
●
Setting of baud rates and parity bits must be identical for all actuators.
EIA-485 termination resistor
The EIA-485 interface module is equipped with an integral fieldbus termination
resistor. The fieldbus termination resistor can be activated and deactivated using a
switch at the lower interface side. The letter T is illuminated at the LED display once
the fieldbus termination resistor is activated. Fieldbus termination resistors are set
in the factory and may not be modified.
Typical cycle time
The cycle for reading any required information depends on the baud rate, the data
volume to be read and the number of connected actuators.
Typical cycle times for searching the actuator position and reading of the most
important status information:
Table 10: Typical cycle times
Typical cycle times (approx.) [ms]
Number of actuators Baud rate
[kbit/s]
60 40 20
900 600 300 115.2
1,200 800 400 57.6
1,500 1,000 500 38.4
2,000 1,400 700 19.2
3,300 2,200 1,100 9.6
18
SIMA² Master Station
Electrical connection and fieldbus connection MODBUS RTU, MODBUS TCP/IP to DCS