3 — PROGRAMMABLE PARAMETERS
pg. 61
Curtis Model 1351 – December 2018
Half-Bridge Drivers
The Half Bridge drivers can be set to operate in two different topologies: Low or High side.
• In Low side topology, the load must be connected to the driver pin and B
+
, Keyswitch or Coil Return.
• In the High-side topology, the load must be connected to the driver pin and B
−
.
The topology mode of the Half-Bridge Drivers is set using its Type parameter. The Half-Bridge (HB) Drivers
use the same control modes as the PWM Drivers. The HB drivers can be used to drive high-side connected
(Coil Return) or low-side connected (B
−
) loads in constant current, constant voltage or PWM % modes.
• Driver 11 = HB Driver 1 (pin 23)
• Driver 12 = HB Driver 2 (pin 35)
OUTPUTS — HALF-BRIDGE DRIVERS
PARAMETER
ALLOWABLE RANGE
DEFAULT
DESCRIPTION
Driver 11
PWM
Driver_X_PWM
Variable’s CAN Index by
Driver_X_
PWM
11 = 0x337A 0x00
12 = 0x337B 0x00
0.0 – 100.0 %
0 – 1000
Read Only
The driver’s Pulse Width Modulation (PWM) percentage.
X= 11 or 12 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\Half-Bridge Drivers\Driver X\PWM
Current
Driver_X_Current
Variable’s CAN Index by
Driver_X_
Current
11 = 0x333A 0x00
12 = 0x333B 0x00
0.000 – 4.000 Amps
0 – 4000
Read Only
The Amperage through HB Drivers 1 or 2.
X= 11 or 12 for the VCL name
Driver_X_Current
This variable is also located in Monitor:
Monitor\Outputs\Half-Bridge Drivers\Driver X\Current
Control Mode
Driver_X_Mode
Parameter’s CAN Index by
Driver_X_Mode
11 = 0x30EA 0x00
12 = 0x30EB 0x00
Off
Direct PWM
Voltage Comp
Current Cntrl
0
1
2
3
Off
0
Sets the mode for HB Driver X
X= 11 or 12 for the VCL name
Driver_X_Mode
0 = Off
(Open mode)
This mode disables the driver.
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.
3 = Current Cntrl
(Current Control)
Regulates the current through the driver. Typically used to
control Proportional Valves (PV). This mode interprets the
command as a load current request to regulate the PWM
(via a PI controller) and thus the requested load current.
