Siemens LMV5 Quick Start Manual page 71

Load Controller
The LMV51.140 and LMV52 are equipped with an internal load controller. The load controller's
primary purpose is to read a temperature or pressure sensor, compare the pressure or temperature
value (known as the Process Variable PV) to the current setpoint, and control the burner load
accordingly. Many different types and ranges of sensors can be wired (Section 3-3) and scaled
(Section 4-2) to cover most temperature and pressure applications. The load controller also has a
Cold Start function so that it can hold the burner at low fire, or slowly step the firing rate until a
temperature or pressure is reached that completely releases the burner to modulate.
The load controller can be operated in six different modes, mode 1 having two different variations.
Figure 4-1.12 details the different modes of the load controller, and what action is taken when a dry
contact is closed between X62.1 and X62.2.
Note: If desired, Terminal X5-03.01 can be deactivated, in effect deactivating the local on/off
switch on the burner. This can be done under parameter InputController. See Section 4-2.
Figure 4-1.12 Operating modes (LC_OptgMode) of LMV51.140 and LMV52 Load controllers
LC_OptgMode parameter is found under: Parameters & Display>Load Controller>Configuration
Mode Label
1A ExtLC X5-03
1B ExtLC X5-03
2* IntLC
3 Int LC bus
4 Int LC X62
5* ExtLC X62
6 ExtLC Bus
* Bumpless transfer (LMV5 will not cycle off) occurs, from Mode 5 > Mode 2, or Mode 2 > Mode 5.
LMV5 QSG Rev 4
Description
External Load Control,
Floating / Bumping
External Load Control,
Staged Oil
Internal Load Control,
Temp. or Press,
sensor connected to
LMV5...
Internal Load Control,
Temp. or Press,
sensor connected to
LMV5...
Internal Load Control,
Temp. or Press,
sensor connected to
LMV5...
External Load Control,
analog signal
connected to X62
External Load Control
via ModBUS
Sec 4 Pg 15
Typical Usage
When using a RWF 40
as the external load
controller, or "toggle
switch" low fire hold.
Externally controlled
2 or 3 stage oil.
Internal Load control
with a Local setpoint.
(Set through AZL)
Internal Load control
with a remote setpoint
via ModBUS.
Internal Load control
with a remote setpoint
via analog input X62
Remote Modulation
control
via analog signal
Remote Modulation
control
via ModBUS
www.scccombustion.com
Upon X62.1
Setpoint - X62.2
Closure
Change to
N/A Mode 2,
Setpoint W1
Change to
N/A Mode 2,
Setpoint W1
Remains in
Mode 2,
W1 / W2
Change to W2
setpoint.
W3
Remote
Setpoint
Change to
Mode 2,
Setpoint W1
N/A
N/A