Demand Signal for Controllers

Demand signals are similar to open loop controller blocks and are written similarly. All of the methods (constant, expression, MotionView, and curve) are applicable for the demand signal as well.

The only difference is demand signals are always open loop signals, therefore TAG = ‘OPENLOOP’ is not required.

Examples

[DEMAND_SPEED]
TYPE = 'CONSTANT'
VALUE = '18.25'

[DEMAND_SPEED]
TYPE = 'EXPRESSION'
SIGNAL_CHANNEL = 0
EXPRESSION = ’10 + SIN(2*TIME)’

[DEMAND_SPEED]
TYPE = 'MOTIONVIEW'
SIGNAL_CHANNEL = 1

[DEMAND_SPEED]
TYPE = ‘CURVE’
BLOCK = ‘SPEED_CRV’
[SPEED_CRV]
INDEPENDENT_VARIABLE = 'PATH_S'
DEPENDENT_VARIABLE = SIGNAL
INTERPOLATION = 'LINEAR'
{PATH_S     SIGNAL}
0           10
50          10
100         10
150         15
200         20
250         25
300         30

One additional method for a demand signal being different from the open loop controller is when defining the signal in a Driver Demand File (DDF). Here you can specify the demand signal at each and every node of the path profile.