ElmoMC SimplIQ Software Manual - Manual (Page 129)

SimplIQ Software Manual The Current Controller
MAN-SIMSW (Ver. 1.4)
9-6
The DC power voltage varies significantly: It decreases at high current due to the power
supply output impedance and increases when, upon braking, the motor acts as a
generator. The division of the bus voltage makes the output of the controller proportional
to the physical motor voltage, eliminating the uncertainty.
The bus voltage is filtered to avoid too rapid changes in current loop PI parameters. The
bus voltage filter is a simple low-pass filter, with a bandwidth of:
32768
] 4 [ XP
log
TS 8
10
6
⋅ π
−
Hz.
The relation between XP[4] and the time constant of the filter is calculated in the table
below for several values of XP[4] and TS=50.
XP[4] Bus Voltage Filter Bandwidth, in Hz
31,750 25 Hz (high impedance supply)
30,720 (factory setting) 50 Hz
28,900 100 Hz (low impedance, high-ripple supply)
Table 9-2: Bandwidth Selections for Bus Voltage Filter
XP[4] is factor set to 30,720. Set it to a higher value if the output impedance of your
power supply is too high, causing an interplay between the filter gains and the DC motor
voltage. Set it to a lower value if you have a very low-impedance power supply, but a
high ripple voltage. In normal applications, it is recommended not to change the factor
setting of XP[4].
9.3 Current Amplifier Protections
The current amplifier and the power stage have several protections, each of which, when
activated, immediately shuts down the drive. If brake action is defined (by the OL[N]
and BP[N] commands; refer to the
SimplIQ Command Reference Manual), the brake is
immediately activated, and in the next 10 milliseconds, the drive will not turn on the
motor, even if instructed to do so.
To determine if the drive has been shut down by a protection:
ƒ
Observe the Motor On and Fault bits in the SR report, or in the CAN special status
object.
ƒ Map the Motor Fault event to an event-drive CAN PDO.
ƒ Poll the MO variable (which drops to 0 on exception).
ƒ Poll the MF variable (which reports a non-zero value after an exception has been
trapped).
ƒ Map a digital output to AOK (refer to the OL command).
You may install an AUTO_ERR routine in your user program to automatically respond to
an exception shutdown.