Brake Processing; Control Mode Processing - Curtis 1298 User Manual

Curtis 1298 Manual,
11
OS

Brake Processing

(Fig. 17)
Braking can be programmed in the 1298 through VCL, as shown in the lower
portion of Figure 17, rather than through a physical brake pot. The VCL pro-
gram manipulates the VCL_Brake variable to get a brake command. Custom
braking functions can be set up in this fashion; e.g., braking based on a switch
position or an internal fault.
After the initial switch, the brake signal passes through a limiter which
limits the brake signal to a range of 0–100% (0–32767). After the limiter the
brake signal is a VCL variable called Mapped_Brake, which is displayed in the
1311 Monitor Inputs menu.
The brake signal then goes through a second selector switch that will set
the brake signal = 0% if the Brake Pedal Enable parameter is set Off. If set On,
the brake signal will pass through. The brake signal after this second selector
switch is a VCL variable called Brake_Command, which is displayed in the
1311 Monitor Inputs menu. Brake command is the final value of the brake
signal chain that is input to the Control Mode Processing block; see Figure 18.
If Brake_Command is non-zero, the throttle signal will be set to 0%.
The following brake processing variables are accessible by VCL:
VCL VARIABLE ACCESS
VCL_Brake Read/Write
Mapped_Brake Read Only
Brake_Command Read Only

Control Mode Processing

Figure 18 begins with the Throttle_Command input. The signal chain is then
directed to Speed Mode Express or Speed Mode or Torque Mode, based on
Control Mode Select.
The control mode function uses algorithms to convert the incoming throt-
tle signal and the motor rpm input into a Controller Torque Command.
The selected control mode calculates the desired Controller Torque Com-
mand, which is passed to the Motor Control block (see Figure 17). The Motor
Control block uses its mathematical model of the specific AC induction motor
used to generate the high efficiency three-phase outputs that are output to the
AC motor via the cables connected to the
DESCRIPTION
VCL-accessible brake command
Brake signal value after mapping
Command resulting from brake processing
and Final AC Motor Control
(Fig. 18)
, , and
U V
7 — VCL
terminals.
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