Curtis 1353 - 4 - PDO Communications; PDO Message Structure and Timing; PDO1-MOSI and PDO2-MOSI Command Data

4 — PDO COMMUNICATIONS
Curtis 1353 CANopen Expansion Module Manual – June 2017 Return to TOC
pg. 20
4 — PDO COMMUNICATIONS
e 1353 is controlled and monitored through four xed communication packets. Each data packet
contains 8 bytes. Two are received by the 1353 from another module (usually the system master) and
in response, the 1353 sends out its packet of data. CANopen calls these packets Process Data Objects
(PDOs). PDO messages have a medium priority.
e PDO communication packets conserve bus bandwidth by bundling the values of a group of
objects into a single message. e content of these PDOs is xed, thus simplifying the interface.
e 1353 normally requires that the PDO-MOSI be cyclic from the master. e cycle time must be
less than the programmed PDO Timeout. If the PDO-MOSI is not received within the programmed
time, the 1353 will ag a fault and disable all output drivers. If the PDO Timeout parameter is set to
0, the timeout fault is disabled and the 1353 will respond to any PDO incoming at any rate without
faulting.
PDO1-MOSI (received from the system master)
Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8
Output 1
Command
Output 2
Command
Output 3
Command
Output 4
Command
Output 5
Command
Output 6
Command
Output 7
Command
Output 8
Command
PDO2-MOSI (received from the system master)
Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8
Output 9
Command
BDI
(0–100%)
[Reserved] [Reserved] [Reserved] [Reserved] [Reserved] [Reserved]
PDO1-MISO (sent in response to the system master)
Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8
Input 1–8
Status
Input 9
Status
6 Virtual
Digital
Inputs
[Reserved] Analog
Input 5
Low Byte
Analog
Input 5
High Byte
Analog
Input 6
Low Byte
Analog
Input 6
High Byte
PDO2-MISO (sent in response to the system master)
Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8
Analog
Input 1
Low Byte
(Encoder1
byte1)
Analog
Input 1
High Byte
(Encoder1
byte2)
Analog
Input 2
Low Byte
(Encoder1
byte3)
Analog
Input 2
High Byte
(Encoder1
byte4)
Analog
Input 3
Low Byte
(Encoder2
byte1)
Analog
Input 3
High Byte
(Encoder2
byte2)
Analog
Input 4
Low Byte
(Encoder2
byte3)
Analog
Input 4
High Byte
(Encoder2
byte4)