Curtis 1239E - VOLTAGE LIMITS

Return to TOC Curtis 1239E-1269E Manual, os 37.0 RevA – May 2021
3 — APPLICATION-SPECIFIC FEATURES
pg. 23
Broken wire protection is provided by the controller sensing the current ow from the pot wiper input
(pin 16 or 17) through the potentiometer and into Pot Low (pin 18). For Type 1 throttles, if the Pot Low
input current falls below 0.65 mA, a throttle fault is generated and the throttle request is zeroed. Note:
Pot Low (pin 18) must not be tied to either of the grounds (low power ground, pin 7, or B–).
Throttle Type 2
With these throttles, the controller looks for a voltage signal at the wiper input. Zero throttle request
corresponds to 0 V and full throttle request to 5V.
A variety of devices can be used with this throttle input type, including voltage sources, current
sources, 3-wire pots, and electronic throttles. e wiring for each is slightly dierent, as shown in
Figure 8, and they have varying levels of throttle fault protection.
When a voltage source is used as a throttle (e.g., a Hall-eect throttle), it is the responsibility of
the OEM to provide appropriate throttle fault detection. For ground-referenced 0–5V throttles, the
controller will detect open breaks in the wiper input but cannot provide full throttle fault protection.
To use a current source as a throttle, a resistor must be added to the circuit to convert the current
source value to a voltage; the resistor should be sized to provide a 0–5V signal variation over the
full current range. It is the responsibility of the OEM to provide appropriate throttle fault detection.
When a 3‑wire potentiometer is used, the controller provides full fault protection in accordance
with EEC requirements. e pot is used in its voltage divider mode, with the controller providing
the voltage source and return. rottle Pot High (pin 15) provides a current limited 5V source to the
3-wire potentiometer, and Pot Low (pin 18) provides the return path. is is the throttle shown in
the basic wiring diagram (Figure 5) for the drive throttle and for the brake throttle.
Complementing the controllers, Curtis oers both Hall-eect and 3-wire potentiometer throttles
which are easily integrated into vehicles.
Hall‑eect voltage throttles:
e Curtis FP Series of throttles oers multiple pedal angles and mounting congurations (oor,
suspended, ush) with 0-5 Volt operation with a Idle Validation Switch (IVS).
e ET-XXX electronic throttle is typically used only as a
drive throttle (illustrated in Fig. 8).
ese voltage throttles contains no built-in fault detection,
and the controller will detect only open wiper faults. It is the
responsibility of the OEM to provide any additional throttle
fault detection necessary.
3‑wire potentiometer throttle:
e FP-10 model oers, besides the controller’s 3-wire fault
detection, two throttle spring detection switches and two
micro-switches to indicate idle validation and full throttle
circuits. This throttle can also be configured from 0-5k
(Type 3) or 5k-0 (Type 1) throttles while retaining the
detection circuits.
For help with a throttle selection, contact the Curtis
distributor or support engineer to discuss the
particular throttle requirements and the application of
Curtis throttles.
Curtis FP-SCV-0022 Hall-effect throttle