ABB DCS550 Series, Manual

Page: 231 / 316

231
Signal and parameter list
3ADW000379R0501 DCS550 Manual e e
Signal / Parameter name
m
in.
ma
x.
def
.
uni
t
50.03 M1SpeedFbSel (speed feedback selector)
Speed feedback selection:
0 = EMF
speed is calculated by means of the EMF feedback with flux compensation, default
1 = Encoder speed is measured by means of a pulse encoder
2 = Tacho speed is measured by means of an analog tacho
3 = External MotSpeed (1.04) is updated by Adaptive Program or overriding control
Notes:
−
It is not possible to go into field weakening range when M1SpeeFbSel (50.03) = EMF.
−
When using EMF speed feedback together with a DC-breaker wrong voltage measurements can lead to
F532 MotOverSpeed [FaultWord2 (9.02) bit 15]. In case of an open DC-breaker the voltage measurement
might show high values caused by leakage currents through the snubber circuits of the thyristors, because
there is no load on the DC side. To prevent these trips set MainContAck (10.21) = DCcontact.
Int. Scaling: 1 == 1 Type: C Volatile: N
EM
F
Ex
te
rn
a
l
EM
F
-
50.04 M1EncPulseNo (encoder 1 pulse number)
Amount of pulses per revolution (ppr) for the pulse encoder.
Int. Scaling: 1 == 1 ppr
Type: I Volatile: N
20 10000 1024 ppr
50.05 MaxEncoderTime (maximum encoder time)
When an encoder is used as speed feedback device the actual speed is measured by counting the amount of
pulses per cycle time. The cycle time for the measurement is synchronized with the mains (every 3.3 ms or
2.77 ms).
In case very small speeds have to be measured - that means there is less than one pulse per cycle time - it is
possible to increase the measuring time by means of MaxEncoderTime (50.05). The speed is set to zero after
MaxEncoderTime (50.05) is elapsed without a measured pulse.
Notes:
−
Formula to calculate the maximum speed using an encoder:
[ ]
ppr
s kHz
rpm n
60 * 300
max
=
with: ppr = pulses per revolution - see M1EncPulseNo (50.04)
−
Formula to calculate the minimum speed resolution using an encoder:
[ ]
cycle
t ppr k
s
rpm n
* *
60
min
=
with: k = 4 (speed evaluation factor)
ppr = pulses per revolution - see M1EncPulseNo (50.04)
t
cycle
= cycle time of the speed controller, either 3.3 ms or 2.77 ms
Int. Scaling: 1 == 1 ms Type: I Volatile: N
3 200 3 ms