Control Techniques has introduced CTSync, a software feature that enables
any installation comprising multiple Unidrive SP ac drives to be
synchronised for multi-axis position control. All the user has to do is
link the drives' SM Applications plug-in modules via an RS485 serial
cable and select CTSync mode from the module. If the modules are already
in use, the cable is the only additional hardware required.
CTSync can be used to create a 'virtual master' within any one of the
interconnected drives. The master can be reassigned dynamically, and any
other configuration changes made, simply by using an optional CTNet link
or any other fieldbus. In this way, problems associated with encoders or
'real' masters can be eliminated - for example, where they are difficult
or impossible to fit on the machine, stability is low or position
references need to be increased, electrical noise is a problem and feed
forward is required.
Using the RS485 port, the feed forward reference signal (speed,
acceleration and so on) gives better stability, with no noise
interference and increased resolution. A complex line reference signal
for any profile is much easier to generate at source rather than
downstream. CTSync provides two 32-bit values and an auxiliary 8-bit
value, and users can assign these to any system parameters. For example,
one 32-bit for high resolution position data, the other for high
resolution velocity data, and the 8-bit for sequencing.