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3 — PROGRAMMABLE PARAMETERS
pg. 53
Curtis Model 1351 – December 2018
PWM Drivers
The ten 1351 Drivers are PWM controlled and have current measurement, output state monitoring
and fault detection functions. Each driver can operate in one of the following modes: Open, Direct
PWM, Voltage Compensated and Constant Current. All drivers operate at >15 kHz PWM. Drivers
are VCL (or CAN message) commanded by directly writing to the variable
Driver_X_Command
,
where the value range of 0 – 1000 corresponds to 0.0% to 100.0%. For example,
Driver_1_Command = 500 ;50% command
0x3360 0x00
In any active driver mode, the driver command, PWM and current can be monitored.
If the Mode is changed while there is a non-zero
Driver_X_Command
, then the Driver PWM is shut
off immediately (no ramping) and is held off until the
Driver_X_Command
is set to zero. After this,
the new mode is in effect and the
Driver_X_Command
can be changed (to a non-zero value).
OUTPUTS — PWM DRIVERS
PARAMETER
ALLOWABLE RANGE
DEFAULT
DESCRIPTION
Driver 1 through 4 X = 1 – 4 for the Driver number (X) which is part of the VCL parameters’ and monitor-variable name
PWM
Driver_X_PWM
Variable’s CAN Index by
Driver_X_
PWM
1 = 0x3370 0x00
2 = 0x3371 0x00
3 = 0x3372 0x00
4 = 0x3373 0x00
0.0 – 100.0 %
0 – 1000
Read Only
The driver’s Pulse Width Modulation (PWM) percentage.
X= 1 – 4 for the VCL name
Driver_X_PWM
100% equates to the driver being fully ON, meaning 100 percent
of the Coil Return voltage (B
+
) is applied to the load (e.g., a
contactor coil).
50% equates to an applied voltage of 50%
0 % turns off the driver.
This variable is also located in Monitor:
Monitor\Outputs\PWM Drivers\Driver X\PWM
Current
Driver_X_Current
Variable’s CAN Index by
Driver_X_
Current
1 = 0x3330 0x00
2 = 0x3331 0x00
3 = 0x3332 0x00
4 = 0x3333 0x00
0.000 – 4.000 Amps
0 – 4000
Read Only
The Amperage through Driver X
X= 1 – 4 for the VCL name
Driver_X_Current
This variable is also located in Monitor:
Monitor\Outputs\PWM Drivers\Driver X\Current
Control Mode
Driver_X_Mode
Parameter’s CAN Index by
Driver_X_Mode
1 = 0x30E0 0x00
2 = 0x30E1 0x00
3 = 0x30E2 0x00
4 = 0x30E3 0x00
Off
Direct PWM
Voltage Comp
Current Cntrl
0
1
2
3
Off
0
Sets the mode for Driver X
X= 1 – 4 for the VCL name
Driver_X_Mode
0 = Off
(Open mode)
This mode is used when the driver output is disabled to
allow the pin to be used as an Input (i.e., Switch 1)
1 = Direct PWM
(normal PWM percentage operation)
The driver’s FET and wiring diagnostics are performed in
this mode.
2 = Voltage Comp
(Voltage Compensated)
Regulates the driver PWM based on the command, the
nominal voltage setting and the present battery voltage in
an attempt to provide a constant average voltage at the
output. As the battery voltage drops, the PWM percentage
will increase to compensate for the lower voltage. The
driver’s FET and wiring diagnostics are performed in this
mode. The initial and continuous PWM percent timing
control is also applied in this driver control mode.