Speed Actual Comparators; Overspeed Limit; Speed Measurement Fault; Stall Protection - ABB DCS 500B Description

Functional Software description
Speed Actual
Comparators

Overspeed limit

Speed Measu-
rement Fault
SPEED ACT (12102)
MON.MEAS LEV (2209)
-1
FIELD1 REV ACK
ACT
-1
+1
EMF ACT (10506)
MON EMF V (2210)

Stall Protection

34
There are four comparators available for speed actual monitoring.
When the speed actual is below the value of parameter MIN
SPEED L (2201), the output MIN SPEED (12201) is set to logical
state 1. This is used as zero speed indication.
Signal output SPEED GT L1 (12202) is active when actual speed is
above speed level SPEED L1 (2202). Parameter SPEED L2 (2203)
and output SPEED GT L2 (12203) have the same function.
The drive can be protected against overspeed e.g. in cases where a
drive section is controlled with the torque reference and the load is
decreasing rapidly. The overspeed limit is set with parameter
OVERSPEEDLIMIT (2204), scale: speed units, range: (0....30 000)
20000 = 100%. Motor overspeed fault (code 37) will be activated, if
overspeed limit is exceeded. Default value is 23000.
The speed measurement supervision is based on the relationship of
the measured speed and measured/calculated EMF. Parameter
MON.MEAS LEV (2209) is the minimum absolute value that the
measured speed must have when EMF ACT (10506) is above the
limit MON.EMF (2210). Otherwise the speed measurement fault is
activated (fault code 14).
MUL
X
SW-C1
MUL
X
-1
Figure 19
The stall protection stops the converter when the motor is in appar-
ent danger of overheating. The rotor is either mechanically stalled
or the load is otherwise continuously too high. The selection of the
stall protection is made by parameter STALL SEL (2205).
0 = stall ptotection disabled
1 = stall protection enabled
The stall protection is activated if the following conditions are full-
filled:
COMP-I
I1 I1>I2
I2 I1=I2
AND2
I1<I2
&
COMP-I
I1 I1>I2
I2 I1=I2
I1<I2
COMP-I
I1 I1>I2
I2 I1=I2
I1<I2
COMP-I
I1 I1>I2
AND2
I2 I1=I2
&
I1<I2
MUL
X
Speed measurement fault logic diagram
SPEED MEAS FAULT
SR
OR2
S
Q
>1
R
-
RESET
DCS 500 Software Description