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Curtis 1298 Manual, OS 11
7 — VCL
Analog Output
This controller has one analog output (pin 30). This output is a special driver
output. The switching stage is filtered to provide a smooth average voltage, in
-
stead of the actual PWM waveform seen on Drivers 1–5. However, AnalogOut
uses the same Put_PWM() and Automate_PWM() used by these other drivers.
The scaling is 0–10V = 0–32767.
Put_PWM(PWM6,6553)
will generate 2.0 volts at the analog output. VCL can monitor this output using
the variable Analog_Output.
INTERFACING THE THROTTLE AND BRAKE COMMANDS
VCL can interface and modify the throttle, brake, and hydraulic throttle signals
at several points; it can be used to create a completely unique command, adjust
parameters to provide MultiMode, or modify the command based on steering
angle, height, etc.
These signal chains within the controller are sophisticated and flexible.
Before applying VCL to modify these chains, it is important to fully under
-
stand the ramifications of these changes. The AC motor command diagram is
presented in Figure 17, and the hydraulic command diagram in Figure 19.
Throttle Processing (Fig. 17)
The throttle signal chain flows left to right starting with the physical throttle
pot. The voltage on the throttle wiper input (pin 16) is input into the control
-
ler and has the VCL variable name Throttle_Pot_Raw which is displayed in
the 1311 Monitor
» Inputs menu. This throttle signal is then modified by the
Throttle Type Processing and Throttle Mapping blocks.
The Throttle Type Processing block combines the Throttle Type parameter
(see page 39) and the throttle potentiometer input (Throttle_Pot_Raw) to cre-
ate a 16-bit variable containing the magnitude of the raw command. This raw
command passes to the Throttle Mapping block, which re-shapes the throttle
signal magnitude and direction based on the various Throttle menu parameters
(see pages 39–41) and the direction inputs.
Following the Throttle Mapping block are two switches whose purpose
is to give the throttle signal a small value (1 for the forward switch, and -1 for
the reverse switch) to indicate that a direction switch is On—but only if the
throttle signal output from the Throttle Mapping block is = 0.
The signal then passes through a selector switch. If the Throttle_Type
parameter is set to 5 (Throttle Type = VCL input, see page 39), the Throttle
Mapping block output signal is ignored and the command comes from the
VCL variable VCL_Throttle. The VCL program manipulates the VCL_Throttle
variable to get a throttle command. When the Throttle Type is set to 1–4, the
variable VCL_Throttle does nothing, and the Throttle Mapping block output
signal passes through.
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