Siemens LMV5 Series Basic Documentation page 239

Standardization
Note
Settling time
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HVAC Products
17.1.3 Configuration of speed acquisition
The speed sensor to be used must be an inductive sensor (Namur or open collector
(pnp) (refer to subsection 15.1.1). The motor speed is acquired with an asymmetric
sensor disk having 3 protrusions spaced at 60°, 120° and 180° respectively. The
number of protrusions must be appropriately parameterized. The sensor disk is to be
fitted such that the pulse intervals are generated in the direction of rotation as described.
Parameter:
Num Puls per R
Since the different types of motors have different maximum speeds, the VSD module must
know the speed that corresponds to 100 %.
Since the standardized speed is difficult to adjust – but the correct adjustment has a
great impact on the control performance of the VSD module – an automatic measurement
function has been implemented.
Parameter:
Standard (deactivated / activated)
When this function is activated, the air actuator will be driven to the prepurge position
first. The air actuator's prepurge position should be adjusted such that the air damper is
fully open.
This action can be watched on the menu «Ratio Control» → «Settings» → «Gas / Oil»
→ «Curve Parameters»
Then, the VSD will be controlled at 95 %. A reserve of 5 % is left, enabling the VSD
module to safely reach the 100 % speed in situations where environmental conditions
may change. Once the motor speed has stabilized, that speed will then be standardized.
In other words, that speed will represent 100 %. That speed can be read using parameter
«StandardizedSp».
Parameter:
StandardizedSp
«StandardizedSp» should not be parameterized manually.
If, based on the steps described above, the burner's rated output cannot be reached
(the fan is controlled at 47.5 Hz), proceed as follows:
Set the maximum frequency to 105.2 % of the motor's nominal speed
−
This means that at a motor frequency of 50 Hz:
Parameterize the maximum frequency of the VSD to 50 Hz
VSD)
Then, standardize
−
This standardization cannot lead to motor overloads since only 95 % of the maximum
control signal is delivered during standardization and the actual speed will be controlled
later in operation and monitored with «Safety time ratio control». Frequencies between
50 and 52.6 Hz are delivered only if this is necessary to reach the required speed due to
increased load.
If automatic speed standardization is activated, or if the standardized speed
is changed, the burner must be readjusted! Any change to the standardized
speed changes the assignment between the parameterized percentages on
the curves and the speed.
If oscillations occur during extensive running times, the settling time between
acceleration ramp and speed measurement can be extended to overcome the problem.
Parameter:
Settling Time (in x
Basic Documentation LMV51...
17 Addendum 3: Variable speed drive (VSD) module
•
1.052 = 52.6 Hz (on the
25 ms) → Value of 16 means 16
•
400 ms (0.4 s)
•
25 ms =
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CC1P7550en
01.10.2003