To help understand how to map internal objects an example VPDO mapping is shown in Figure
22. A digital switch input is mapped to the seat switch function to control the traction application,
i.e. with no seat switch input the vehicle is prevented from moving.
Figure 22 Example of a digital input mapped to the seat switch via VPDO
The number of sub-indices of each VPDO object depends on the amount of I/O on the device.
For example, 3300
h
has 14 sub-indices on a device with 8 digital inputs and 5 analogue inputs.
Sub-index 0 gives the number of I/O channels in use. In 3300
h
sub-indices 1 to 8 correspond to
the digital inputs and sub-indices 9 to 14 correspond to the digital state of analogue inputs.
To map the local I/O to an application signal object, set the appropriate VPDO sub-index to the
application signal object index. If the seat switch shown in the above diagram was connected to
digital input 4 (bit 3 in 6800
h
,1), sub-index 4 of 3300
h
would be set to 2124
h
.
Some further examples are:
Map FS1 to read the value of digital input 8 (connector A, pin 11): at 3300
h
sub-index 8
enter the value 2123
h
.
Map the electromechanical brake signal to be applied to analogue output 2 (customer
connector, pin 7): at 3200
h
sub-index 2 enter the value 2420
h
.
The data flow direction between the application signal objects and the local I/O objects depends
on whether they are inputs or outputs. For inputs, the flow is from the local I/O to application
objects, and vice versa for outputs.
Motor VPDOs are slightly different. There are six parameters for each motor, some of which flow
from application to local I/O (controlword, target torque and target velocity) and some of which
flow from local I/O to application (statusword, actual torque and actual velocity).
PDO mapping
The controller supports 5 RPDOs (receive PDOs) and 5 TPDOs (transmit PDOs). Up to 8 Object
Dictionary entries can be mapped to each PDO. Every PDO must have a unique identifier (COB-
ID).
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