Wesley BC-620-4CA - Manual (Page 94)

90 Curtis 1234/36/38 Manual,
OS
11
7 — VCL
To set up the brake pot input for use in VCL, use the Brake_Pot constant
in place of the Thottle_Pot constant in the Setup_Pot function.
Setup_Pot(BRAKE_POT,TWO_WIRE)
will set up the brake pot input for wiring using two connections (pins 17, 18).
The 0–100% position of the potentiometer is represented by a value from
0–32767 in VCL. Once set up (through the VCL Setup_Pot() function) the
potentiometer value is automatically and continuously loaded into the variable
Throttle_Pot_Output or Brake_Pot_Output. It is important to use the correct
setup (
ONE_WIRE , TWO_WIRE , or THREE_WIRE ) since the input is automatically
re-scaled for 0–100% based on the wiring used; for example, the voltage at the
Pot Low pin is automatically subtracted and re-scaled on a
THREE_WIRE pot.
Another effect of setting the Throttle Type = 5 is that the signal chain
for the throttle now gets its input from a different source. The input to the
throttle chain is now a VCL variable called VCL_Throttle instead of the
throttle pot. Similarly, Brake Type = 5 means the brake signal chain will get
its input from a VCL variable called VCL_Brake rather than from the brake
pot. The VCL_Throttle and VCL_Brake variables will need to be controlled
in the VCL program.
One of the unique features of the potentiometer inputs (as opposed to the
analog inputs) is that they have automatic pot fault detection functions run-
ning in the motor controller OS. The VCL programmer has access to the pot
detection functions with the Setup_Pot_Faults() function. With this function,
VCL can set the high and low threshold at which a fault occurs. This function
also forces the pot value to a definable level if a fault occurs. Note that the
Setup_Pot_Faults() function will work for all throttle Types (1–5). See page 108
for more detail on this function.
Analog Inputs
These controllers have two generic analog inputs (pins 24 and 8). These are
shared as switch inputs 1 and 2 (Sw_1, Sw_2). The values of the analog inputs
are automatically placed in VCL variables Analog1_Input and Analog2_Input
every 1 millisecond. Scaling is 0–10V = 0–32767.
User2 = Analog2_Input
will fill the User2 RAM variable with the value of the voltage at pin 8.
The filtered values of the analog inputs are also available and are auto-
matically placed in VCL variables Analog1_Filtered and Analog2_Filtered.
Scaling is 0–10V = 0–32767. The default filter value is 328 (10 Hz) and can
be changed in VCL by changing the Analog1_Filter and Analog2_Filter values.
Scaling is 0–999Hz = 0–32767.
Analog Output
These controllers have one analog output (pin 30). This output is a special
driver output. The switching stage is filtered to provide a smooth average
voltage, instead of the actual PWM waveform seen on Drivers 1–5. However,