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GWY-01-DNT-01 MANUAL – REV. 02 CHAPTER 5:

DEVICENET INTERFACE

PAGE 54 OF 67

The image below displays an example of the data contained in the two I/O Controller

Tags for the Gateway.

Figure 5-7: Gateway I/O Controller Tags (in RSLogix 5000)

5.2.5 DeviceNet - Handshaking Example

This example describes the sequence of events for a simple command and

response. All data is written in 2-byte WORD format and stored in 2-byte “registers.”

The Output Controller Tag holds command data written by the PLC. The Input

Controller Tag holds response data generated by the Gateway. Handshaking is

implemented using the first two words (Words 0 and 1) in both Input Controller Tag

and Output Controller Tags.

1. The PLC writes a command to the Output Controller Tag, starting with the 2-byte

Consume Data Size value at Local:2:O.Data [2] (which is the third register of the

Output Controller Tag). The remainder of the command packet is then written, 2-

byte per register, to the Output Controller Tag, starting at the fourth register,

Local:2:O.Data [3]. After writing the command packet data to the appropriate

registers, the PLC increments the counter value stored at Local:2:O.Data [1]

(the second register in the Output Controller Tag).

2. The counter at Local:2:O.Data [1] is copied by the Gateway to Local:2:I.Data

[0] (the first register of the Input Controller Tag) which signals the PLC that the

command has been received by the Gateway.

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Datalogic GWY-01-PBS-01 Dokumentacja Strona 54