Pdo Communications - Curtis 1352 Manual

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Curtis 1352 eXm Manual,

PDO COMMUNICATIONS

The Curtis eXm is easily controlled and monitored through two fixed
communication packets. Each data packet contains 8 bytes. One is received by
the eXm from another module (usually the system master) and in response, the
eXm 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 Curtis CANopen implementation requires that the incoming PDO-
RX (MOSI) be responded to by an outgoing PDO TX (MISO). The eXm will
respond to the PDO-RX (MOSI) with its PDO-TX (MISO) within 4 ms.
The eXm normally requires that the PDO-RX (MOSI) be cyclic from the
master. The cycle time must be less than the programmed PDO Timeout. If the
PDO-RX (MOSI) is not received within the programmed time, the eXm will
flag a fault and the eXm will disable all output drivers. If the PDO Timeout
parameter is set to 0, the timeout fault is disabled and the eXm will respond to
any PDO incoming at any rate without faulting. Take care using this setting as
the last PDO commands will stay on the eXm indefinitely.
The 1352's PDO-TX (MISO) can also be set to cyclical transmission every
4ms to 1000ms rate as soon as the eXm put in Operational Mode. Finally, the
PDO-TX (MISO) can be set to one of 5 types. Each type sends a different set
of internal data. Type 0 is the present default.
PDO-RX (MOSI)
Byte 1 Byte 2
Output 1 Output 2
Command Command
PDO-TX (MISO): Type 0
Byte 1 Byte 2*
Virtual
Inputs 1-6 Inputs
Status (lower 3
PDO-TX (MISO): Type 1 Driver PWM
Byte 1 Byte 2*
Virtual
Inputs 1-6 Inputs +
Status 1 (upper
nibble)
Rev. D
(received from the system master)
Byte 3 Byte 4
Output 3 Output 4
Command Command
Byte 3 Byte 4
Analog Analog
Input 1 Input 1
Low Byte High Byte
bits)
Byte 3 Byte 4
Driver 1 Driver 2
PWM % PWM %
(0-100) (0-100)
4 — PDO COMMUNICATIONS
Byte 5 Byte 6 Byte 7
Output 5 Output 6
Not Used
Command Command
Byte 5 Byte 6 Byte 7
Analog Analog Analog
Input 2 Input 2 Input 3
Low Byte High Byte Low Byte
Byte 5 Byte 6 Byte 7
Driver 3 Driver 4 Driver 5
PWM % PWM % PWM %
(0-100) (0-100) (0-100)
Byte 8
Not Used
Byte 8
Analog
Input 3
High Byte
Byte 8
Driver 6
PWM %
(0-100)
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