> For the complete documentation index, see [llms.txt](https://docs.andymark.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.andymark.com/frc-electronics/koors40-brushed-speed-controller/pwm-only-am-5600.md).
# PWM Only (am-5600)
### I. Introduction
The Koors40 Brushed Speed Controller is designed to provide lower-cost, precise control for brushed DC motors. This manual will guide you through the operation, features, and basic troubleshooting of the device. This speed controller incorporates protection features such as overcurrent protection and thermal management for robust and reliable operation.
> **NOTE:** In the servo world the input control signal is referred to as PWM (Pulse Width Modulation). For consistency, this manual will use the PWM abbreviation. The technically correct abbreviation for this type of signal is PPM (Pulse-position Modulation).
***
### II. Key Features
**Input Voltage Range:**\
6 V to 18 V
**Maximum Current:**\
40 A
Depending on ambient temperature and installation conditions, the controller may enter thermal shutdown after approximately four minutes at a continuous current near 40 A.
**PWM Input Range:**\
1000 µs to 2000 µs
The controller accepts signals from 500 µs to 2400 µs, but full output is mapped to 1000 µs (full reverse) and 2000 µs (full forward).
#### Protection Features
* **Reverse Polarity Protection:** Prevents damage if power is connected backwards (no power passes through).
* **PWM Ground Protection:**
* Protects against input power ground loss
* Current limit fuse causes motor chirps if ground lost
* Prevents motor current flowing through PWM ground (which could cause damage)
* **Overcurrent Protection:** Derates the PWM output if current exceeds **65 A for 3 seconds**.
* **Overtemperature Protection:** Shuts down at approximately 212 °F (100 °C).
#### Operating Modes
* **Brake Mode:** Brings the motor to a quick stop.
* **Coast Mode:** Allows the motor to spin down freely.
***
### III. Operation
#### Connection Setup
1. Disconnect power before making or changing connections.
2. Connect a 6 V–18 V power source, observing polarity.
3. Connect the brushed DC motor to the output terminals.
4. Connect the PWM control signal to the input terminal.
5. To toggle between **Coast** and **Brake** mode, carefully press the Coast/Brake button with a small, nonconductive tool.
***
### IV. LED Status Indicators
The Koors40 has an integrated LED that gives visual feedback on its status:
| State | Condition | Signal | LED Indicator | Visual | Description |
| --------------- | ------------------- | ------------- | ------------------------- | ------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------- |
| No PWM Input | Brake | No Signal | Blinking Blue |  | Controller is in Brake Mode and does not have a valid signal |
| PWM Input | Brake | Valid Signal | Solid Blue |  | Controller is in Brake Mode and getting a valid neutral signal |
| No PWM Input | Coast | No Signal | Blinking Yellow |  | Controller is in Coast Mode and does not have a valid signal |
| PWM Input | Coast | Valid Signal | Solid Yellow |  | Controller is in Coast Mode with a valid signal |
| Partial Forward | Running | PWM > 1500 µs | Blinking Green |  | Motor is running forward at partial power |
| Full Forward | Running | PWM = 2000 µs | Fast Blinking Green |  | Motor is running forward at full power |
| Partial Reverse | Running | PWM < 1500 µs | Blinking Red |  | Motor is running in reverse at partial power |
| Full Reverse | Running | PWM = 1000 µs | Fast Blinking Red |  | Motor is running in reverse at full power |
| Fault | Gate Driver/Thermal | Error | Slow Blinking Orange/Cyan |  | Gate driver fault, no power, or thermal shutdown (212 °F) |
| Fault | Overcurrent | Error | Blinking Red/Orange |  | Overcurrent fault (>65 A for 3 s) |
***
### V. Safety Precautions
Follow these safety guidelines to ensure safe operation and prevent damage to the Koors40 Brushed Speed Controller.
* **Proper Wiring:** Verify power polarity and all connections before energizing the controller.
* **Voltage Limits:** Do not exceed the 18 V input limit.
* **Environmental Conditions:** Do not expose the controller to water, conductive debris, or extreme temperatures.
* **Power Protection:** Use properly rated branch-circuit protection and provide a way to disconnect power quickly.
* **Overheating:** If the controller reaches approximately 212 °F (100 °C) internally, it enters thermal shutdown. This may occur after approximately four minutes near 40 A, depending on ambient temperature and installation conditions. See [IV. LED Status Indicators](#iv.-led-status-indicators). Reduce the motor load and allow the controller to cool before restarting.
* **PWM Signal Integrity:** In electrically noisy environments, the use of shielded cables for PWM input is recommended to prevent signal noise and erratic motor behavior.
***
### VI. Troubleshooting
#### Common Issues & Solutions
If you encounter any issues while using the Koors40 Brushed Speed Controller, refer to this guide for possible causes and solutions.
| Issue | Possible Cause | Solution |
| ------------------------------------------------------------------------ | ------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| No Motor Response | • No power
• Faulty wiring
• No PWM signal
| • Confirm all power connections are secure and battery voltage is within range
• Verify correct polarity; the controller will not receive power if polarity is reversed
• Check that the controller is receiving a valid PWM signal
|
| Motor Stutters or Jerks | • Poor PWM signal quality or connection | • Check PWM wiring or try a different servo tester or receiver |
| Motor output "choppy"
LED Indicator Slow Blinks Red and Orange
| • Overcurrent fault | • Reduce motor load
• Allow the controller to cool down and restart
|
| Motor output "choppy"
LED Indicator Slow Blinks Orange/Cyan
| • Thermal Shutdown fault | • Reduce motor load
• Allow the controller to cool down and restart
|
[Contact AndyMark support for further troubleshooting help](mailto:support@andymark.com)
***
### VII. Resources
* [Koors40 product page](https://andymark.com/products/koors40-brushed-dc-motor-controller)
* [Koors40 user manual](https://s3.amazonaws.com/docusync-files/0e9a3a8e3ac79752d90f426e15439897d4570a12bbcecc0769b2317757f48d95/am-5600%20Koors40%20User%20Manual.html)