DESIGNER’S HANDBOOK 4189350049C EN
Page 138 of 206
11.7 CANopen TPDO/RPDO input adjust
11.7.1
PDO converter for azimuth/rudder
The azimuth angle in the virtual indicator used in this example is predefined in the VS profile to come from an angle
transmitter (encoders) with CANopen interface (for example DEIF RTC 300 or RTC 600). The transmitter sends the
measured angle b/-180
o
represented by a signed 16 bit relative data value packed into a TPDO in byte 0
and 1. This means that the input data value range is: -32768 to 32767.
To receive a TPDO or RPDO, the built-in
tool called a “PDO converter” is used to convert the incoming relative
angle value to an absolute angle value b/-180.0
o
. That will then be presented on the XDi azimuth
indicator. A PDO converter input is only available if it is defined as the data source in the selected VS profile.
This type of input can be used for any standard angle transmitter (encoder) with CANopen interface according to
“CiA 406 Device profile for encoders”. It will be possible to adapt to most of those CAN transmitters by adjusting the
standard parameters in the TPDO converter as explained below, but if this is not possible due to a special
configuration of the CANopen angle transmitter, it may be necessary to make a customised VS profile.
Name:
is a unique name for this data type and instance. It makes it easier to
identify the data source. The name
may be edited from the menu, using the virtual keyboard and can be synchronised via XDi-net.
Source:
is the input source type that is defined in the selected VS. It is fixed for PDO converters, and if XDi-net and
XDi-net variable data are active, it will also be possible to send data using the XDi-net data protocol. This makes it
possible to use either PDO or XDi-net format even if the source is a PDO converter. Do not send XDi-net data to
this data type/instance in parallel with the TPDO specified in the converter. This will make the azimuth indicator
jump between the received values. This function can be useful to establish a backup function in a system, for
example if the PDO transmitter fails, a CAN master/controller can send backup data in XDi-net format.
Zero ref.:
makes it possible to insert a zero reference (or offset) to the received angle value.
Data type:
defines the data type that is
used for this indicator and is fixed (cannot
be changed via menu).
Data instance:
is used to separate
multiple azimuth transmitters on the same
CAN bus. It is a fixed defined number
typically between 1 and 15.
The “Data type” and “Instance” defines
the Obj.index where data is stored.
(See the XDi-net/CANopen reference
manual for details)
Most transmitters on CAN are delivered with auto-start. If the sensor does not use auto-start on
CANopen, then XDi can be set up to send out the CANopen start command after boot up. This function
is located in the CAN setup menu.
