User's Manual

COBALT UHF-SERIES CHAPTER 6: ETHERNET/IP INTERFACE
PAGE 99 OF 140
6.8.2 Ethernet/IP Handshaking Example
In the example below, EMS_READ1 is the name of the Read Tag and EMS_WRITE1
is the name of the Write Tag.
NOTE: [0] indicates the first word, [1] indicates the second word in a controller tag.
1.
The PLC writes the command to the Read Tag (EMS_READ1) and then
increments the counter in EMS_READ1 [1]
2.
The counter in EMS_READ1 [1] is copied by the Cobalt to EMS_WRITE1 [0]
which acknowledges that the command has been received.
3.
Following execution of the command, the Cobalt copies the response to
EMS_WRITE1 (the Write Tag) and increments the counter in EMS_WRITE1 [1].
This signals that there is new data for the PLC (the Cobalt generated response,
in this case).
WRITE TAG (where responses are written by the Cobalt)
EMS_Write1 [0] = (2) the Cobalt copies counter here to ACK
EMS_Write1 [1] = (3) the Cobalt increments this counter to signal response available
EMS_Write1 [2] = Data Size
EMS_Write1 [3-102] = Data
READ TAG (where commands are retrieved by the Cobalt)
EMS_Read1 [0] = (4) PLC copies the counter here to ACK the response
EMS_Read1 [1] = (1) PLC increments this counter after writing a command
EMS_Read1 [2] = Data Size
EMS_Read1 [3-102] = Data