SSD Drives 590+ Series, Product Manual, Page: 145 / 319

6-38
Programming Your Application
590+ Series DC Digital Converter
FIELD CONTROL
Parameter Tag Range
EMF LAG 176 0.00 to 200.00
This is the lag time constant adjustment of the field weakening PID loop
With a default of 4.00, real time constant = 4000ms.
EMF GAIN 177 0.00 to 100.00
This is the gain adjustment of the field weakening PID loop.
With a default of 3.00, real gain = 30.
MIN FIELD CURRENT 179 0.00 to 100.00 %
(MIN FLD.CURRENT)
The field weakening loop reduces the field current to achieve speed control above base
speed. At top speed the field reaches a minimum value. MIN FIELD CURRENT should be
set below this minimum value to allow reasonable margin for transient control near the top
speed but not lower than 6% as this could then cause the "Field Fail" alarm to operate.
MAX VOLTS 178 0.00 to 100.00 %
Maximum volts is the voltage level at which field weakening begins. It is also known as
"Spillover Bias". The default value is 100% of the nominal value as set by the armature
voltage calibration value. For commissioning purposes this value can be set to another
(lower) desirable level. Subsequently, it is advisable to return it to 100% for normalisation.
BEMF FBK LEAD 191 10 to 5000
This is the lead time constant of the back emf feedback filter which is used for reducing
armature voltage overshoots when accelerating fast through base speed.
BEMF FBK LAG 192 10 to 5000
This is the lag time constant of the above feedback filter. If the filter is active, the ratio of
lead / lag should always be greater than 1 to give an overall lead action which reduces the
voltage overshoot and less than, typically, 3 for stable control. The default values 100/100 =
1 cancel each other and make the filter inactive.
FLD. QUENCH DELAY 185 0.0 to 600.0 s
(FLD.QUENCH DELAY)
If dynamic breaking is used the field must be maintained for a period after the drive is
disabled until the motor reaches zero speed. The field quench delay is the period of time
that the field is maintained for when the drive is disabled.
FLD. QUENCH MODE 186 QUENCH / STANDBY
After the field quench delay has expired, the field can be entirely quenched or put into a
standby mode at 50% of rated current or volts depending whether in current or voltage
control mode respectively. (The default standby value of 50% can be modified through the
"SYSTEM / Reserved" Menu which is primarily for factory use only and requires the
“super” password.)
FIELD I THRESHOLD 617 0.00 to 100.00 %
Threshold for UP TO FIELD diagnostic.