D.I.P. CDN366, User Manual

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CDN36X User Manual revision 1.30
The Receive Acknowledge bits are bit-mapped into the second byte of the DeviceNet I/O
Command Message. Serial Receive Object Instance 1 Receive Acknowledge bit maps to bit 0,
Instance 2 maps to bit 1, etc. The Receive Toggle bits are bit-mapped into the second byte of the
DeviceNet I/O Response Message. Serial Receive Object Instance 1 Receive Toggle bit maps to
bit 0, Instance 2 maps to bit 1, etc. This bit mapping makes it easy for ladder-logic applications
to implement the gateway’s receive-synchronization process. The following 2 ladder-logic rungs
show how an application program can monitor for an instance’s
Receive Toggle , copy the new
Receive Data value to save it, and set the Receive Acknowledge bit equal to the Receive Toggle
bit. These rungs should be duplicated for each enabled Serial Receive Object instance.
|
bit = 1 bit = 0
|
|------[ RX Toggle ]-------[ /RX Ack ]--------------------|------------( copy RX Data to variable )--------|
|
| |
| |--------------------( RX Ack )---------------------|
| bit =1 |
| bit = 0 bit = 1 |
|------[ /RX Toggle ]------[ RX Ack ]---------------------|------------( copy RX Data to variable )--------|
|
| |
| |--------------------( /RX Ack )--------------------|
| bit =0 |
Transmit Synchronization
The gateway transmit synchronization is always enabled for each Serial Transmit Object
instance. An instance will not process its Transmit Data output bytes until its Transmit Toggle
bit changes state. When the user application sends new Transmit Data to an instance, is must
toggle that instance’s Transmit Toggle bit. This enables the Instance to process the new output
value and load the resulting serial message into the transmit buffer. When the message is loaded
for transmission, the Instance acknowledges transmission by setting its
Transmit Acknowledge
bit equal to the Transmit Toggle bit. The application can now send the next Transmit Data
value. The Transmit Toggle and Transmit Acknowledge bits are set to 0 at power-up.
The
Transmit Toggle bits are bit-mapped into the first byte of the DeviceNet I/O Command
Message. Serial Transmit Object Instance 1 Transmit Toggle bit maps to bit 0, Instance 2 maps
to bit 1, etc. The Transmit Acknowledge bits are bit-mapped into the first byte of the DeviceNet
I/O Response Message. Serial Transmit Object Instance 1 Transmit Acknowledge bit maps to bit
0, Instance 2 maps to bit 1, etc. This bit mapping makes it easy for ladder-logic applications to
implement transmit synchronization. The following 2 ladder-logic rungs show how an
application program writes an instance’s
Transmit Data value, toggles the Transmit Toggle bit,
and waits for the Transmit Acknowledge bit to equal the Transmit Toggle bit before writing the
next Transmit Data value. These rungs should be duplicated for each enabled Serial Transmit
Object instance.
MKS Instruments, Inc. D.I.P. Products Group 26