Siemens LMV5 Quick Start Manual page 191

Step by Step Commissioning of the VSD Control 7-3
After verifying that the wiring from the LMV52 to both the speed wheel and the VFD are
correct and all system components are grounded properly the VSD can be set-up, and
commissioned.
Note: Verify that the arrow on the speed wheel points in the desired direction of rotation.
If not, the wheel can be turned over and re-mounted so that the speed wheel arrow is
in the correct direction.
1. Set / Check the relevant parameters in the LMV52. All parameters related to the
LMV52 VSD control are outlined in Section 4-2 of the Quick Start Guide.
The following parameters should be checked for most applications:
a. Under Ratio Control > Gas / Oil settings > VSD, activate the VSD.
If the burner is dual fuel, the VSD must be activated for gas and oil.
b. Also set the air actuator to air influen. (under gas and oil)
c. Under Ratio Control > Times, set the ramp times.
Both OperatRampMod and TimeNoFlame should be set to at least 10
seconds longer than the ramp rate programmed into the VFD.
Typically the VFD is 30 seconds, so these should be set to 40 seconds.
d. Under VSD Module > Configuration > Speed > Num Puls per R,
change Num Puls per R to 6 if a six fingered speed wheel is used.
(The default setting of Num Puls per R is 3.)
e. Under VSD Module > Configuration > Speed > Setpoint Output,
verify that Setpoint Output signal is set to 4-20mA instead of 0-20mA.
2. Set / Check the relevant VFD parameters. (on the VFD drive itself)
Many parameters must be set in the VFD for the specific application such as motor
HP, max / min motor speed, number of motor poles, service factor, etc..
Although the names of the actual VFD parameters may change by manufacturer,
VFD settings specific to using a LMV52 VSD control with a VFD are:
a. Span the VFD input signal so that 4mA = 0 Hz and 20mA = 62.5 or 63 Hz.
b. Set the VFD so that it starts and runs on a contact closure. The dry contact
that closes in the LMV52 is rated 24 VDC, on terminals X73.1 and X73.2.
c. Set the VFD ramp rate so that it is able to ramp more quickly than the
LMV52. A ten second differential (as explained in step 1) works well for most
applications. Also note that faster VFD ramp rates will generate higher
amperage for both the motor and the VFD.
d. Set the VFD so that it sends an alarm signal to the LMV52 in the event of a
VFD problem, such as over-current.
The 12-24 VDC alarm input is terminal X73.3 on the LMV52.
e. Make sure that no PID loops or filtering exist on the VFD input signal, so that
19.5 mA input directly produces a 60 Hz VFD output, an 11.7 mA input
directly produces a 30 Hz output etc... The LMV52 VSD control already
contains an application-tuned PID loop, and "stacked" PID loops do not
provide accurate control. In short, the VFD needs to be programmed as a
slave device.
LMV5 QSG Rev 4 Sec 7 Pg 7 www.scccombustion.com