Network Management (Nmt; Pdo (Process Data Object - Delta DVP-15MC Series Operation Manual

DVP-15MC Series Motion Controller Operation Manual
C.2

Network Management (NMT)

The CANopen network management complies with the Master/Slave mode. Only one NMT
master can exist and other nodes are considered as slaves in a CANopen network. NMT
contains three types of services, Module control services, Error Control services and Boot-up
services. Please refer to section C.1 of the manual for more details.
C.3

PDO (Process Data Object)


PDO

The PDO provides the direct visit channel for the device application object, is used to transmit
the real-time data, and has high priority. Every byte in the PDO CAN message data list is used
to transmit the data. The rate of making use of the message is high.

The PDO is described by means of the "producer/consumer mode". The data is transmitted
from one producer to one or many consumers. The data which can be transmitted are limited to
1-byte data to 8-byte data. After the data is transmitted by the producer, the consumer does not
need to reply to the data. Every node in the network will detect the data information transmitted
by the transmission node, and decides whether to process the data which is received.

There are two kinds of PDO services for every PDO: TxPDO and RxPDO. The PDO sent by
the producer is called PDO (TxPDO) sent by the producer device. And the PDO the consumer
receives is called PDO (RxPDO) which the consumer device receives.

Every PDO is described with two objects in the object dictionary: The PDO communication
parameters and the PDO mapping parameters.
The PDO communication parameters:
Include the COB-ID which will be used by PDO, transmission type, prohibition time and the
cycle of the counter.
The PDO mapping parameters:
Contain the object list in an object dictionary. These objects are mapped into the PDO,
including the data length (in bits). To explain the contents of the PDO, the producer and the
C
consumer have to understand the mapping.

The PDO transmission modes: synchronous and asynchronous
Synchronous: Synchronous periodic and synchronous non-periodic
Asynchronous: The PDO is transmitted when the data is changed, or it is transmitted after an
event trigger.

The transmission modes supported by PDO are as follows.
1 – 240
254
255
Mode 0: The PDO information is transmitted only when the PDO data is changed and the
synchronous signal comes.
Modes 1~240: One piece of PDO information is transmitted every 1~240 synchronous signals.
Mode 254: The event trigger transmission is defined by the manufacturer. For DVP-15MC series
motion controller, the definition is the same as mode 255.
Mode 255: PDO is transmitted when the data is changed, or it is transmitted after an event trigger.
C-6
Type
Periodic Non-periodic
0
X
PDO transmission
Synchronous Asynchronous
X X
X
RTR
X
X