ABB DCS 500B, Description

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Functional Software description
DCS 500 Software Description 55
Activating The field reversal function is enabled by means of parameter FIELD
MODE (1001)
0 [CONSTANT F] no EMF-control
1 [EMF, NO FIELD REV] EMF-control without field reversal
2 [NO EMF, FIELD REV] Field reversal
3 [EMF + FIELD REV] Field rev. + EMF-control
4 [NO EMF, OPTITORQUE] Field rev. + OPTITORQUE
5 [EMF + OPTITORQUE] Field rev. + OPTI
EMF-control
On a four-quadrant drive the field reference value is always positive
100% (4095). If the EMF-controller is activated, the field current is
controlled but it still can never be larger than 100%.
Field direction
change hystere-
sis To avoid a too sensitive field reversal function when the torque ref-
erence value is close to zero, a parameter is needed to form a
hysteresis around the zero torque reference. The hysteresis is
symmetrical around zero. For exampe, the hysteresis value is 80.
The drive will change to reverse field when the torque reference is -
80 or smaller. Back to forward field the drive can change when the
torque ref is +80 or larger.
REV.REF HYST (1319) (default 80)
Force field direc-
tion It is possible to force the drive to use a specified field direction. This
gives the user the possibility to allow a change of field direction only
when it is needed. For example, it is known when the drive must
really change the direction of speed. Using the force-command
makes the drive less sensitive to the value of the torque reference.
Two inputs are defined for forcing the field direction:
[F1 FORCE FWD] (1302)
[F2 FORCE REV] (1303)
Field monitoring
when changing
direction Normally the field current is compared with the minimum level and if
the current falls below the limit, all the control functions are blocked
and the drive goes to state RDY RUN = 0 and RDY REF = 0. Dur-
ing the field change the situation differs. The current can be below
the minimum field level for a certain time because the field current
must pass over zero.
In the process of field changing the current controller and the speed
controller I-part are blocked and the speed ramp output is updated
by the actual speed value.