- Full datasheet can be downloaded from:
An enhanced version is currently under development:
-SPI 20Mhz control channel
-RS232 115200 control channel
-Configurable Input filters
SPECIPICATIONS Controller's highlights
1. Maximum continues output current of 25A.
2. Maximum input voltage 20v.
3. Optional – electrical braking.
4. Build in 5v / 700mA regulator.
5. SPI communication 10Kbps.
6. PID control and feedback can be done in SPI-Command, Pulse-signal or analog-signal.
7. User selectable PWM frequency range from 31.25HZ up to 4 KHz with up to 16bit resolution.
8. User programmable PID-Bypass-Channel with conversion look-up-table of 256x8bit (64bytes with 4 point interpolation).
9. User programmable feedback sensor conversion look-up-table of 512x16bit (64words with 8 point interpolation).
10. User programmable 1 st order IIR filter for control signal (N/A)
11. User programmable 1 st order IIR filter for feedback signal (N/A)
12. Real-time build-in-test with configurable fault-masking register.
13. Hardware-reset to factory defaults option.
- Connectors and pinout Power-In: Flying leads Vin, GND
Power-Out: Flying-leads Vin, SW (open collector)
I/O: Molex Right-Angle PicoBlade socket 8pin (SD53261-0871)
- PID CONTROLLER GENERAL DESCRIPTION
The PID-controller is a device capable of regulating the output of the device being controlled to a specific control signal (the wanted value). It is doing so by the following iterative way:
- Reading the control-signal (wanted-output) and applying to it some numerical adjustments by using configurable look-up-table and offset value.
- Measuring the system feedback (real-output) signal and applying to it some numerical adjustments by using configurable look-up-table and offset value.
- Calculating the error between the control and feedback signals and calculating the new value to be outputted to the connected device in order to reduce the error (PID + feed-forward method).
- Wait for the next system cycle (dT) and loop to stage 1.
And in even more simple explanation, for example: if the actual temperature is less then the wanted temperature the PID-controller will deliver more power to the connected heating device until a zero difference between the desirable and available values will be achieved.
The PID controller is suitable for controlling and stabilizing many systems e.g.:
- Motors RPM
- Room's light-intensity.
- Wind-tunnel wind velocity
The output of the PID-Controller is PWM signal (Pulse-Width-Modulation). It means that by switching the load to the energy source for different amount of times (Pulse width) the average power being delivered to the connected device can be adjusted.
The PID-Controller can read almost any analog or digital signal, and has SPI-bus.
The analog signal can be any 0-5v signal with sensitivity of 5[mV] (10bit resolution)
The digital signal can be any 0-2v / 3-5v signal with selectable timing resolution of 0.5 to 4[uS]
Or minimum Pulse-Repetition-Interval (PRI) of 0.5[mS]
The PID-controller is fully configurable and in certain operation mode can be monitored in real-time during its operation.
For safety reasons, the PID-controller software is equipped with real-time Built-In Test (RT-BIT) to ensure the system is operating in its normal region. The BIT algorithm is as follow:
- Detection the absence of feedback or control signal.
- Detection if the system excides the normal output vs. feedback values. By monitoring that the output and feedback signals are in normal, user configurable, operation range.
If the user activates the BIT, any detection of the above events will put the PID-Controller in shutdown mode.
Control-Loop Structure Graphical representation of PID-Controller transfer function
- Smart-PID Unique features
Additional to the classic PID control-loop structure, the Smart-PID controller has the following unique features:
- Feedback & control signal offset value – can be used to compensate for signal bias issues or to convert unsigned readings to sign value.
- Bypass channel with look-up-table – can be used to enhance transition-settling time or compensate for non-linearity issues of the load.
- Programmable bypass pre-scaler (1:1, 1:4, 1:16, 1:256) – can be used to adjust the raw control signal values to the 8bit input of the Bypass-LUT.
- Programmable bypass post-scaler (x1, x4, x16, x256) – can be used to adjust the 8bit output of the bypass LUT to the 16bit value of the control-loop.
- Feedback with lookup table – can be used to calibrate gain, offset and non-linearity issues of the feedback signal.
- Feedback invert – Simple mechanism to negate the feedback value if needed.
- Feedback programmable pre-scaler (1:1, 1:2, 1:64) – can be used to adjust the raw feedback value to the feedback-LUT 9bit input.
- Real-time Build-In-Test - In order to prevent from the controller to work in a case of a system malfunction, a continuous test is being performed every system-cycle. The test will detect whether the feedback and PID-output signals values are exceed the programmed valid region. If abnormality is detected for 7 consecutive cycles, the controller will automatically change to ‘OFF’ mode and set a 'Fault' flag until user intervention or next reset.
Full datasheet can be downloaded from: