Siemens LMV3 series User Manual

Technical Instructions LMV Series
Document No. LV3-1000
Section 7 Page 14 SCC Inc.
Operating Modes
Changing between
«local» and
«remote» mode
After activating Modbus communication, data can be exchanged between the
LMV3 and the Modbus master via the Modbus interface.
Preselection of the target output via Modbus can only be made after the Modbus
mode has been switched from «local» to «remote». This change is made by
writing to Modbus address 41.
The preselection of the target output that was made previously has no impact and
is set «invalid» when changing to remote operation.
The presetting after activation of Modbus communication is «local». When the
LMV3 is switched off, the mode is set back to the presetting.
Changeover of
Modbus operating
mode between
«auto», «remote
on», and
«remote off»
This setting is used to determine the behavior of
the system in remote operation.
The setting is made by writing to Modbus address 43.
With the «auto» setting, the output to be delivered is determined by the LMV3.
With the «remote on» setting, the Modbus master determines the output to be
delivered by the system by predefining a target output.
With the «remote off» setting, the burner will be shut down. A new start is made
only when the operating mode changes to «remote on» and a new preselection of
target output is made, or after a change to local operation.
For output preselection via the building automation and control system, the
controller on contact on the LMV3 must be closed.
The presetting after activation of remote operation is «auto». When the LMV3 is
switched off, the operating mode will be reset to the preselected mode.
Monitoring of
Modbus timeout
If communication between the Modbus and the
LMV3
is interrupted
, the
length
of time that the interruption lasts will be monitored. Every permissible Modbus
communication on the LMV3 will restart monitoring.
Monitoring only takes place in «remote» operation. If the time parameterized for
communication timeout (Modbus address 42) is exceeded, a change from remote
to local operation will take place. In that case, the system travels to the
parameterized preselected output to be delivered in the event of a
communication breakdown (Modbus address 84/85).

If the time is
exceeded, remote operation must be selected again by the Modbus
master. Upon a return of communication, addresses 41 and 43 and the
preselected output must be written again. Only then can the output be
readjusted. Timeout is a Modbus parameter and is retained even if the LMV3 is
switched off.
Bus behavior in the event of burner lockout
If the LMV3 has triggered a lockout due to a fault, the selected operating mode with remote mode
(Modbus addresses 41 and 43) will be retained when the unit is reset. For the required target output to
be reached, all that is required is to preselect the output again via Modbus address 45.

Siemens LMV3 series Specifications

General

Brand	Siemens
Model	LMV3 series
Category	Control Unit
Language	English