22 • vacon
nx interface
Tel.+358-(0)201-21
Tel. +358 (0)201 2121 • Fax +358 (0)201 212 205
7
7.3
Process data (PDO)
The real-time data transfer is performed by means of ”Process Data Objects” (PDO). The transfer of
PDOs is performed with no protocol overhead. Process Data is time-critical data used for control of
the drive and monitor status of the drive. Transmit PDOs support several transmission modes which
are cyclic, acyclic, synchronous, asynchronous and RTR only mode. Most PDOs support also Event
Timer for transmitting PDOs. TPDO1 is exception which is defined for asyncronous only operation.
Receive PDOs support only asyncronous transmission mode (event driven). Vacon CanOpen option
board uses 8 types of PDOs as follows:
Cy
cl
ic
A
cy
cl
ic
Sy
nc
hr
ono
us
A
sy
nc
hro
no
us
(d
ef
au
lt
RT
R O
nl
y m
od
e
Ev
en
t T
im
er
PDO
Type
Mapped Data
Mapped Data
Mapped Data
Mapped Data
TPDO1
statusword
-
-
-
x
TPDO6
statusword
vl_control_effort
-
-
X
X
X
x
X
X
TPDO21
nx_status_word
nx_actual_speed
process_data_out
1
process_data_out
2
X
X
X
x
X
X
TPDO22 process_data_out3 process_data_out4 process_data_out5 process_data_out6 X
X
X
x
X
X
RPDO1
controlword
-
-
-
x
RPDO6
controlword
vl_target_velocity
-
-
x
RPDO21 nx_control_word
nx_speed_reference process_data_in1
process_data_in2
x
RPDO22 process_data_in3
process_data_in4
process_data_in5
process_data_in6
x
Note: manufacturer specific PDOs (TPDO21/RPDO21/ TPDO22/RPDO22) consist of application specific
process data. See appendix for contents of these processdatas in different applications. See Chapter
7.6 (Using manufacturer specific PDOs) or a specific application manual.
Note! all Tx objects are event-driven by default. (Message is sent out if one or several values within
the message change)