Rockwell Automation 1769-ADN Compact I/O 1769-ADN DeviceNet Adapter User Manual

Page 182

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Publication 1769-UM001B-EN-P - October 2002

B-24 Explicit Messaging Application Examples

Error Reply (Hexadecimal)

Description (High Byte/Low Byte)

0101

TXID

1

/Command

2

0002

Port #

3

/Byte Count

4

9413

Service

5

/Mac ID

6

xxxx

Bad Status for the Configuration Command

1

TXID (Transmission ID) is used by the scanner to track the transaction to completion and returns the same value

with the reply. To properly track commands with their replies, this value should be incremented for each new

command sent. TXID size is one byte.

2

Command instructs the scanner on how to administer the request. “01” is the Execute This Transaction Block

command. The command data size is one byte. Refer to the 1747-SDN User Manual, publication 1747-5.8, for

list of supported commands.

3

Port # is the physical channel of the scanner where the transaction is to be routed. The port # must be 0

(channel A) and the data size is one byte.

4

Byte Count identifies the number of bytes in the transaction body. The transaction body begins with word 3 and

the data size is one byte.

5

Service specifies the type of request being delivered. “10” is a Single Parameter Write. In the reply, the high bit

of this byte is set, so 90 represents a good reply to the Single Parameter Write service, while 94 indicates that

the Set Configuration command contained an error. The error code can then be found in the next word of the

reply (or word 4). Service data size is one byte.

6

Mac ID is the DeviceNet network node address of the device for which the transaction is intended. The slave

device must be listed in the scanner module’s scan list and be online for the explicit message transaction to

complete successfully. The Mac ID value must be hexadecimal. In this example, the node address of the

1769-ADN adapter is 19 decimal or 13 hexadecimal. The Mac ID data size is one byte.

7

Class is the desired DeviceNet class. “030C” hexadecimal is the class code for the object representing 1769

I/O. The class data size is one word.

8

Instance represents the slot number of the I/O module we want to configure. This analog output module is in

slot 10 or “000A” hexadecimal.

9

Attribute identifies the specific characteristic of the object towards which the transaction is directed. “001A”

hexadecimal (26 decimal) represents Configuration Data. The attribute data size is one word.

10 Configuration data is 8 words in length, although only 6 words contain actual configuration data. The last two

words must be included, but must be 0000 hexadecimal. The actual configuration data information may be

found in the Compact I/O Analog Module User Manual, publication 1769-6.0. Chapter 5 of that publication

shows the layout of the six configuration words for the 1769-OF2 module.

The first two words of the configuration file configure channels 0 and 1 respectively for such features as the

output data format (Raw/Proportional Data for this example) and output type (4-20mA for the example).

The next four words are values for the two channels in the event the controlling processor faults or is placed

into the Program mode. For this example, these four values must be in the range of 6241 or 31207 decimal

(1862 to 79E7 hexadecimal), which represents 4-20mA. Any values out of this range will result in a

configuration error.

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