Diagnostic link commands – Rockwell Automation 2755 Enhanced Decoder Series B User Manual

Page 279

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16–14

PCCC Host Commands

Publication 2755-833

0

5

00H

TNS

High Byte

Low Byte

LSB

1

3

2

6

08H

Example (holds output closed for 10 milliseconds)

4

7

MSB

06H

60H

00H

0AH

Important: A duration of 0000 holds the specified output in the
programmed state until it is changed with another host command or
via the AUX terminal configuration screens. The condition field on
the AUX terminal will display Open or Closed.

The diagnostic commands (06H) allow you to obtain diagnostic data
on an DH485 communications link. The decoder supports these
diagnostic commands:

Diagnostic Loop (CMD= 06H, FNC= 00H)

Read Diagnostic Counters (CMD= 06H, FNC= 01H)

Read Diagnostic Status (CMD= 06H, FNC= 03H)

Reset Diagnostic Counters (CMD= 06H, FNC= 07H)

The command code for all diagnostic functions is 06H. A function
code (FNC) identifies each command and specifies which command
to perform.

Diagnostic Loop

The Diagnostic Loop Command (CMD= 08H, FNC= 00H) echoes
data back to the host. The reply returns the same data sent in the
Diagnostic Loop Data area of the command. The data area can
contain up to 122 bytes.

Diagnostic Link
Commands

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