2
10 MOVIDRIVE®Serial Communication
MOVILINK® and system bus
System bus
(SBus)
The SBus is a CAN bus in accordance with the CAN specification 2.0, parts A and B. It
supports all services in the SEW MOVILINK®unit profile. In addition, you can exchange
IPOSplus® variables via the SBus independently of the profile.
The unit behavior of the inverter which forms the basis of CAN operation is referred to
as the unit profile. It is independent of any particular fieldbus and is therefore a uniform
feature. This provides you, the user, with the opportunity of developing applications
regardless of the fieldbus.
MOVIDRIVE®offers digital access to all drive parameters and functions via the SBus.
The drive inverter is controlled via high-speed process data. These process data
telegrams let the user enter setpoints, such as the setpoint speed, ramp generator time
for acceleration/deceleration, etc. and trigger various drive functions such as enable,
control inhibit, normal stop, rapid stop, etc. You can also use these telegrams to read
back actual values from the drive inverter, such as the actual speed, current, unit status,
error number and reference signals.
The exchange of parameter data via the MOVILINK®parameter channel lets you create
applications in which all important drive parameters are stored in the programmable
master controller. This means there is no need to manually set the parameters on the
drive inverter itself, which is frequently a rather time-consuming task. IPOSplus®
provides the MOVLNK command for the exchange of parameter data and process data
with other MOVILINK®stations. As a result, MOVIDRIVE®can operate as the master
via IPOSplus® and control other units.
The process data and the drive parameters can be sent to a synchronization telegram
synchronously or asynchronously.
Using the SBus requires additional monitoring functions such as time monitoring (SBus
timeout delay) or special emergency-off concepts. You can adapt the monitoring
functions of MOVIDRIVE®specifically to your application. You can determine which
error response the drive inverter should trigger in the event of a timeout. A rapid stop is
a good idea for many applications, although this can also be achieved by "freezing" the
last setpoints so the drive continues operating with the most recently valid setpoints (e.g.
conveyor belt). You can still implement emergency-off concepts which are independent
of the bus and use the terminals of the drive inverter because the functions of the control
terminals are still active when the SBus is in operation.
02244BEN
Fig. 5: Variants of SBus communication
PD1 PD2 PD3
PD1 PD2 PD3
E
Q
IPOS
plus®
E
Q
IPOS
plus®
Parameter
PD1 PD2 PD3
MOVILINK protocol
®
Variable exchange
Max. 8 data bytes = 2 variables, each 32 bit
System bus (SBus)
