Receiving a user defined CAN message
Section 4-6
47
transferred to the PLC.
Clearing the buffer
After a reset or after power-on, the buffer is only cleared when a new IOWR
message with control code #0004 is successfully executed. This means that
the buffer is also cleared when the same IOWR message (with the same
identifier values) is indicated to the Unit.
Example
The following example shows how an arbitrary CAN message is read. In this
example, the Machine number is set to ‘1’.
Assume that there is a 32-bit counter unit on the network that transmits its
actual count value every time the count changes. On average, the count
changes every 2 ms. The identifier of the message is 280h. Another node
transmits its 8-bit input value every 4 ms with identifier 282h. A third node
transmits its 16-bit clock value every 200
µ
s with identifier 281h.
The scan time of the PLC is fixed to 8 ms. The C200HW-CORT21 only wants
to receive the 32-bit counter value and the 8-bit input value. The Unit does
not want its receive buffer to be filled with the high frequent clock messages.
The received messages must be transferred to DM0600.
14.00
IOWR (-)
Indicate_Identifier
#0004
DM0500
#1004
255.06
12.00
EQ_FLAG
ERROR
PLC memory address
Contents
DM0500
0280
DM0501
0282
DM0502
0001
DM0503
0600
DM0600
0006
DM0601
0280
DM0602
0004
DM0603
1004
DM0604
000F
DM0605
0000
DM0606
0000
DM0607
0280
DM0608
0004
DM0609
1003
DM0610
000F
DM0611
0000
DM0612
0000
Summary of Contents for C200HW-CORT21
Page 1: ...C200HW CORT21 CAN Unit OPERATION MANUAL Cat No W904 E2 1...
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Page 5: ...C200HW CORT21 CAN Unit Operation Manual Produced July 2000...
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Page 24: ...Performance Section 1 3 22...
Page 40: ...LEDs 7 Segment Display Section 3 3 38...
Page 56: ...Maintenance Section 5 3 54...
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