Rockwell Automation 900 Temperature Controller Communications Functions - Series B - Manual (Page 78)

Publication 900-UM004D-EN-E - July 2010
4-20 Modbus Communications Procedure
· Moving the Protect function group in Manual Mode
When this operation command is issued in manual mode, an Operation
Error will be generated, and the move to the Protect function group will
be prohibited.
· Auto/Manual Switch
This operation command switches the mode to manual mode or
automatic mode, based on the related information setting. This
command can be accepted in Setup Area 0 only. An Operation Error
will be generated in the following instances:
– When the command is executed in Setup Area 1
– When auto/manual switching is disabled (not displayed)
When the Controller is switched to manual mode, the Manual
Manipulated Variable will be displayed. When the Controller is switched
from manual mode to automatic mode, the Operation function group’s
first parameter will be displayed. When the Controller is switched to
manual mode while already in manual mode, the command will be
completed normally and the display will not change (the contents will
not be refreshed).
· Writing Auto/Manual Status in EEPROM
The write mode determines whether the auto/manual status is written
to EEPROM.
➊ When the auto/manual mode is switched with an operation command through communications and the
Controller is in RAM write mode, the auto/manual status is not stored in EEPROM. Consequently, if the
Controller is restarted by performing a software reset or turning the power OFF and ON again, the auto/manual
mode is set to the last saved status.
Table 4.16
Write Mode Description
Backup mode When the auto/manual mode is switched by
communications, the auto/manual status is written to
EEPROM. ➊
RAM write mode When the auto/manual mode is switched by
communications, the auto/manual status is not written to
EEPROM. The status can be written with the Controller key
operations. ➊