BECKHOFF BC3150 - Manual (Page 54)

Safety Instructions
52 Fieldbus Components
TwinCAT PLC
The Beckhoff TwinCAT Software System turns any compatible PC into a real-time controller with a multi-PLC system,
NC axis control, programming environment and operating station. The TwinCAT programming environment is also
used for programming the BC/BX. If you have TwinCAT PLC (Windows NT4/2000/XP) installed, you can use the
fieldbus connection or the serial port for downloading and debugging software. If you are programming with TwinCAT
BC (also compatible with Windows 95/98/ME), the connection to the BC is made exclusively via the serial port.
TwinCAT I/O or TwinCAT PLC can also be used as the Ethernet Master (host), in order to exchange process data
with the Bus Terminal Controller. TwinCAT provides you with the System Manager as a configuration tool, as well as
the drivers and the ADS protocol.
Bus Terminal Controller of BX series and BCxx50
These 2nd-generation Bus Terminal Controllers are configured with the TwinCAT System Manager and programmed
with TwinCAT PLC Control. TwinCAT PLC has to be installed (Windows NT4, Windows 2000, Windows XP) for these
couplers.
Minimum requirement: TwinCAT from Version 2.9 build 940
Programming and program transfer
•
via the serial interface
•
via the fieldbus interface (only at Bus Terminal Controllers for PROFIBUS, CANopen and Ethernet)
Online Change
The Bus Terminal Controller of BX series and BCxx50 supports online change. This means that the PLC program is
replaced with a new program without interrupting the program. The switch-over to the new program occurs after the
task is completed. This means that two versions of the PLC program have to be stored. 512 kB are available, which
therefore have to be divided by 2, leaving 256 kB for the actual program. In addition, several kB are required for task
configuration etc. During an online change, dynamic data are stored in memory. Should a program approach the
memory limit (program size greater than 240 kB), the online change may no longer work, even though the program
may still be written to the BX after "Rebuild all".
When is online change not available?
Online change is not available under certain conditions
•
Inserting of a new library
•
Change in task setting
•
"Rebuild all"
•
Controller memory limit is almost reached (PLC program greater than 90%)