ABB DCS 500B User Manual

Functional Software description
DCS 500 Software Description 37
• Torque Reference
The function of the torque reference chain is to form a desired ref-
erence for the current regulation.
TORQ_REF_SELECTI
ON function block
An external torque reference can be connected via analog inputs.
AI2 function block is connected to [TREF A] (2401) in the standard
program, and this input contains a filter controlled by parameter
TREF A FTC (2402) (1000 = 1s), 0 = not in use.
[TREF B] (2404) input is another torque reference input, which
contains the ramp generator function controlled by parameter
TREF B SLOPE (2405) (1000 = 1s), 0 = not in use.
Torque Refer-
ence Scaling
The value 4000 is equal to nominal torque of the DC-motor (T
N
).
Therefore the analog input must be scaled according to this value.
For example, an external torque reference -10V...+10 V is con-
nected to analog input AI2 and the torque reference should be
-100%...+100% of the motor nominal torque. The parameter set-
tings are:
AI2 CONV MODE (107) = 1
AI2 HIGH VALUE (108) = 4000
AI2 LOW VALUE (109) = -4000
Load sharing in
Master / Follower
Application
The load of the follower drive can be adjusted by means of input
[LOAD SHARE] (2403) to the desired value by the application
function blocks. The default value is 100 % = 4000.
The output OUT (12401) is calculated:
[TREF A] x [LOAD SHARE] / 4000 + [TREF B]
Output Limitation The final torque reference before limitation is a sum of a [TREF A]
multiplied by [LOAD SHARE] and [TREF B].
The output OUT (12401) can be limited by internal signals [TREF
TORQMAX1] and [TREF TORQMIN1] in the function block
TORQUE / CURRENT LIMITATION.
TORQUE/CURRENT_
LIMITATION function
block
Torque / Current Limitation function block consist of limitation cir-
cuits for torque and current references and gear backlash compen-
sation.
Current Limita-
tions
The limitation of armature current is based on fixed current limit pa-
rameters and on limits which are the function of the actual speed.
There is a function block with given points of speed and maximum
current on these points. Finally the current limit selection is based
on a maximum/minimum selection of these two limitation sources.

ABB DCS 500B Specifications

General

Brand	ABB
Model	DCS 500B
Category	Media Converter
Language	English