Rockwell-automation 900 Temperature Controller Communications Function Bedienungsanleitung PDF herunterladen (Seite 71)

Publication 900-UM004D-EN-E - July 2010

Modbus Communications Procedure 4-13

Writing Undisplayed Parameters

It is possible to write the parameters that are not displayed due to display

settings as well as the parameters that are never displayed in the Controller.

Table 4.10

Name Description

Slave address The value from the command frame is entered as-is.

Function code This is the received function code.

When the function ended normally, the function code is left as-is.

When an error occurred, the hexadecimal value of H’80 is added

to the function code to indicate that the response is an error

response.

Example: Received function code = H’10

Function code in response frame when an error occurred = H’90

Write start address This is the received write start address.

Number of elements This is the received number of elements.

CRC-16 This check code is calculated with the data from the slave

address to the end of the data.

For details on the CRC-16 calculation, refer to CRC-16 Calculation

Example in on page 5-2.

Table 4.11 Response Code

Function Code Error Code Error Name Cause

H’90 H’02 Variable address error The write start variable address is incorrect.

The variable area number is incorrect.

H’03 Variable data error • The amount of data does not match the number of

elements.

• The byte count is not 2 times the number of elements.

• The write data is out of the setting range.

H’04 Operation error The Controller cannot write the data in its present operating

status.

The write data contents are not allowed in the present

operation mode.

• The Communications Writing parameter is set to OFF

(disabled).

• Attempted to write to a parameter in Setup Area 1 from

Setup Area 0.

• Attempted to write to a Protect parameter from other than

the Protect function group.

• AT execution in progress

H’10 — Normal completion No errors were found.

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Rockwell-automation 900 Temperature Controller Communications Function Bedienungsanleitung Seite 71