Siemens LMV3 series, Technical Instructions

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LMV Series Technical Instructions
Document No. LV3-1000
SCC Inc.
Page 11 Section 5
Standardized Speed - Standardizing the LMV3
After the VSD blower is installed, wired and programmed correctly (see Section 2 for wiring), the LMV3
must be standardized.
The purpose of the standardization (calibration) procedure is to establish a relationship between the
speed signal sent to the VSD (0-10 VDC or PWM) and the actual speed (RPM) of the blower wheel. This
is done by correlating the speed signal to the actual RPM at two points: Near maximum speed and also
when the blower is stopped.
The near maximum speed is read by sending either a 95% or 98% speed signal to the VSD, and then
recording what speed was achieved. On the minimum speed side, 0% speed signal is assumed to be 0
RPM. The electronics in the LMV3 then “draw a line” between these two points (linear interpolation) to
establish the expected speed response of the blower to a given speed signal. See Figure 5-4.
The standardization procedure is automated, and is activated by setting parameter 641 to a value of 1.
When this is done, the following should occur:
1.
The air damper is opened to pre-purge position.
2. The blower output (X3-05.1) is energized, closing a relay and enabling the VFD (if equipped).
3. A 95% or 98% speed signal is applied to the VSD. This can be a 0-10 VDC or a PWM signal. If
parameter 661 is set to 0, then a 95% signal will be used. If parameter 661 is set to 1, a 98% signal
will be used.
4. The blower ramps up to speed. After the speed has stabilized, the actual RPM is recorded by the
LMV3 and is stored under parameter 642.
5. The speed signal is returned to 0%, and the blower is allowed to ramp down.
6. The blower output (X3-05.1) is de-energized.
7. The air damper returns to its home position.
8. If a value of 0 appears on the AZL after standardization, then the procedure was completed without
error. If a value appears other than 0, see Error Code 82 in Section 6 of this manual.
NOTE: The LMV3 will not standardize if the safety loop is open, or if the burner switch is on. Ensure
that the safety loop is closed and the burner switch is off before attempting to standardize.
A typical standardization process for a 2-pole (~3600 RPM) three phase blower with VFD is shown
graphically in Figure 5-3. If a standardization was performed on a brushless DC blower (PWM blower)
the procedure would be similar but the peak blower speed would be substantially higher (typically 5,500
RPM to 14,000 RPM) and the speed signal used for standardization would be 98% due to parameter 661
being set to a value of 1 for a PWM blower.