Watson-Marlow Qdos30 - Manual (Page 17)

Watson-Marlow qdos30 PROFIBUS Pump User Manual 17
11 PROFIBUS control wiring
Interfacing the pump with the PROFIBUS network is by means of an M12 connector
mounted on a flying lead on the front of the pump.
It is the user’s responsibility to ensure the safe and reliable operation of the pump
under PROFIBUS control.
Note: The transmission speed is limited to a maximum of 1.5Mbit/s.
11.1 PROFIBUS installation
All devices in the bus system must be connected in a line. An IP66 rated T adaptor
should be used to connect the pump to the PROFIBUS line. A maximum of 32 stations
(to include master, slaves and repeaters) are possible and both the beginning and
the end of the cable must be terminated with a terminating resistor.
The M12 socket provided for PROFIBUS installation is IP66 rated. To maintain an
IP66 rated system the PROFIBUS cable, T adaptors and terminating resistors used
must be fitted with IP66 rated M12 industrial connectors.
Note: To prevent low-frequency ground loops, screening which is earthed at one end
should be used. To counter magnetic HF pick-up, shielding earthed at both ends as well as
twisted conductors should be used, this will have no effect against electrical HF pick-up.
The permissible overall length of the bus cabling will vary according to the required
bit rate. If a longer cable or higher bit rate are required repeaters should be used.
The maximum bit rates achievable are shown in the table below.
Bit rate (Kbit/s) Max. length of type A bus cable (m)
1500 200
500 400
187.5 1000
93.75 1200
19.2 1200
9.6 1200
Note: Total stub length should not exceed 6.6m