4: Pdo Communications - Curtis 1353 User Manual

Curtis 1353 CANopen Expansion Module Manual – June 2017
The 1353 is controlled and monitored through four fixed 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.
The PDO communication packets conserve bus bandwidth by bundling the values of a group of
objects into a single message. The content of these PDOs is fixed, thus simplifying the interface.
The 1353 normally requires that the PDO-MOSI be cyclic from the master. The cycle time must be
less than the programmed PDO Timeout. If the PDO-MOSI is not received within the programmed
time, the 1353 will flag 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
PDO2-MOSI
PDO1-MISO
PDO2-MISO
pg. 20
4 — PDO COMMUNICATIONS
(received from the system master)
Byte 1 Byte 2 Byte 3
Output 1 Output 2 Output 3
Command Command Command
(received from the system master)
Byte 1 Byte 2 Byte 3
Output 9 BDI [Reserved]
Command (0–100%)
(sent in response to the system master)
Byte 1 Byte 2 Byte 3
6 Virtual
Input 1–8 Input 9
Digital
Status Status
Inputs
(sent in response to the system master)
Byte 1 Byte 2 Byte 3
Analog Analog Analog
Input 1 Input 1 Input 2
Low Byte High Byte Low Byte
(Encoder1 (Encoder1 (Encoder1
byte1) byte2) byte3)
Byte 4 Byte 5 Byte 6
Output 4 Output 5 Output 6
Command Command Command
Byte 4 Byte 5 Byte 6
[Reserved] [Reserved] [Reserved]
Byte 4 Byte 5 Byte 6
[Reserved] Analog Analog
Input 5 Input 5
Low Byte High Byte
Byte 4 Byte 5 Byte 6
Analog Analog Analog
Input 2 Input 3 Input 3
High Byte Low Byte High Byte
(Encoder1 (Encoder2 (Encoder2
byte4) byte1) byte2)
Return to TOC
Byte 7 Byte 8
Output 7 Output 8
Command Command
Byte 7 Byte 8
[Reserved] [Reserved]
Byte 7 Byte 8
Analog Analog
Input 6 Input 6
Low Byte High Byte
Byte 7 Byte 8
Analog Analog
Input 4 Input 4
Low Byte High Byte
(Encoder2 (Encoder2
byte3) byte4)
4 — PDO COMMUNICATIONS