ElmoMC SimplIQ Software Manual - Manual (Page 199)

SimplIQ Software Manual Limits, Protections, Faults and Diagnosis
MAN-SIMSW (Ver. 1.4)
13-4
13.2 Speed Protection
The reference to the speed controller is limited to the range [VL[2]…VH[2]]. The limiting
(applied on the total of the software reference and external reference) is made by the stop
manager.
In addition to the speed limiting, the SimplIQ drive provides two forms of speed
protection:
ƒ
Speed-following error protection (ER[2])
ƒ Over-speed limit protection (HL[2]/LL[2])
The first protection detects an over-speed error. The ER[2] parameter specifies the limit
for the velocity error. If the absolute value of the speed tracking error VE exceeds ER[2],
the
SimplIQ drive issues the exception MF=0x80 and the motor is shut down
automatically.
The second protection detects over-speed. If VX is greater than HL[2] or less than LL[2],
the
SimplIQ drive issues the exception MF=0x20,000 and the motor is shut down
automatically.
The over-speed protection is active in all unit modes. The speed for over-speed detection
is always derived from the main position sensor; this means that in dual-loop systems
(UM=4), the motor speed (the inner loop) — and not the load speed (the outer loop) — is
over-speed protected.
The speed command and feedback limits are illustrated in the following figure. The drive
normally operates in the area marked “Within command and feedback limits.” However,
it may, momentarily, visit areas marked “Overshoot area” due to overshoot, and this is
acceptable. If the speed feedback reaches the “Abort area,” the drive will issue an over-
speed exception and the motor will be shut down automatically.
0
W ith in sp e e d co m m a n d a n d
fe e d b a c k lim its
V L [2 ] V H [2 ]
L L [2 ] H L [2 ]
W ith in s p e e d fe e d b a c k lim its, o u t o f
co m m a n d lim its .
A b o rt
A re a
A b o rt
A re a
O ve r-
s h o o t
A re a
O ve r-
s h o o t
A re a
Figure 13-2: Speed Command and Feedback Limits
Remember that when the drive shuts down due to an exception, the motor
continues to run on its own inertia unless brakes are used (refer to
section
13.6 ).