forked from M-Labs/thermostat
193 lines
7.6 KiB
Markdown
193 lines
7.6 KiB
Markdown
# Firmware for the Sinara 8451 Thermostat
|
|
|
|
- [x] [Continuous Integration](https://nixbld.m-labs.hk/job/stm32/stm32/thermostat)
|
|
- [x] [Download latest firmware build](https://nixbld.m-labs.hk/job/stm32/stm32/thermostat/latest/download-by-type/file/binary-dist)
|
|
|
|
|
|
## Building
|
|
|
|
### Debian-based systems (tested on Ubuntu 19.10)
|
|
|
|
- install git, clone this repository
|
|
- install [rustup](https://rustup.rs/)
|
|
|
|
```shell
|
|
rustup toolchain install nightly
|
|
rustup update
|
|
rustup target add thumbv7em-none-eabihf --toolchain nightly
|
|
rustup default nightly
|
|
cargo build --release
|
|
```
|
|
|
|
The resulting ELF file will be located under `target/thumbv7em-none-eabihf/release/thermostat`
|
|
|
|
|
|
## Network
|
|
|
|
### Connecting
|
|
|
|
Ethernet, IP: 192.168.1.26/24
|
|
|
|
Use netcat to connect to port 23/tcp (telnet)
|
|
```sh
|
|
nc -vv 192.168.1.26 23
|
|
```
|
|
|
|
telnet clients send binary data after connect. Enter \n once to
|
|
invalidate the first line of input.
|
|
|
|
|
|
### Reading ADC input
|
|
|
|
Set report mode to `on` for a continuous stream of input data.
|
|
|
|
The scope of this setting is per TCP session.
|
|
|
|
|
|
### Commands
|
|
|
|
| Syntax | Function |
|
|
| --- | --- |
|
|
| `report` | Show current input |
|
|
| `report mode` | Show current report mode |
|
|
| `report mode <off/on>` | Set report mode |
|
|
| `pwm` | Show current PWM settings |
|
|
| `pwm <0/1> max_i_pos <ratio>` | Set PWM duty cycle for **max_i_pos** to *ampere* |
|
|
| `pwm <0/1> max_i_neg <ratio>` | Set PWM duty cycle for **max_i_neg** to *ampere* |
|
|
| `pwm <0/1> max_v <ratio>` | Set PWM duty cycle for **max_v** to *volt* |
|
|
| `pwm <0/1> <volts>` | Disengage PID, set **i_set** DAC to *ampere* |
|
|
| `pwm <0/1> pid` | Set PWM to be controlled by PID |
|
|
| `center <0/1> <volts>` | Set the MAX1968 0A-centerpoint to *volts* |
|
|
| `center <0/1> vref` | Set the MAX1968 0A-centerpoint to measure from VREF |
|
|
| `pid` | Show PID configuration |
|
|
| `pid <0/1> target <value>` | Set the PID controller target |
|
|
| `pid <0/1> kp <value>` | Set proportional gain |
|
|
| `pid <0/1> ki <value>` | Set integral gain |
|
|
| `pid <0/1> kd <value>` | Set differential gain |
|
|
| `pid <0/1> output_min <value>` | Set mininum output |
|
|
| `pid <0/1> output_max <value>` | Set maximum output |
|
|
| `pid <0/1> integral_min <value>` | Set integral lower bound |
|
|
| `pid <0/1> integral_max <value>` | Set integral upper bound |
|
|
| `s-h` | Show Steinhart-Hart equation parameters |
|
|
| `s-h <0/1> <t0/b/r0> <value>` | Set Steinhart-Hart parameter for a channel |
|
|
| `postfilter` | Show postfilter settings |
|
|
| `postfilter <0/1> off` | Disable postfilter |
|
|
| `postfilter <0/1> rate <rate>` | Set postfilter output data rate |
|
|
| `load` | Restore configuration from EEPROM |
|
|
| `save` | Save configuration to EEPROM |
|
|
| `reset` | Reset the device |
|
|
| `ipv4 <X.X.X.X>` | Configure IPv4 address |
|
|
|
|
|
|
## USB
|
|
|
|
The firmware includes experimental support for acting as a USB-Serial
|
|
peripheral. Debug logging will be sent there by default (unless build
|
|
with logging via semihosting.)
|
|
|
|
**Caveat:** This logging does not flush its output. Doing so would
|
|
hang indefinitely if the output is not read by the USB host. Therefore
|
|
output will be truncated once buffers are full.
|
|
|
|
|
|
## Temperature measurement
|
|
|
|
Connect the thermistor with the SENS pins of the
|
|
device. Temperature-depending resistance is measured by the AD7172
|
|
ADC. To prepare conversion to a temperature, set the Beta parameters
|
|
for the Steinhart-Hart equation.
|
|
|
|
Set the base temperature in degrees celsius for the channel 0 thermistor:
|
|
```
|
|
s-h 0 t0 20
|
|
```
|
|
|
|
Set the resistance in Ohms measured at the base temperature t0:
|
|
```
|
|
s-h 0 r0 10000
|
|
```
|
|
|
|
Set the Beta parameter:
|
|
```
|
|
s-h 0 b 3800
|
|
```
|
|
|
|
|
|
## Thermo-Electric Cooling (TEC)
|
|
|
|
Connect the Peltier device to the TEC0/1-/+ outputs.
|
|
|
|
### Limits
|
|
|
|
Each of the MAX1968 TEC driver has analog/PWM inputs for setting
|
|
output limits.
|
|
|
|
Use the `pwm` command to see current settings and maximum values.
|
|
|
|
| Limit | Unit | Description |
|
|
| --- | :---: | --- |
|
|
| `max_v` | Volts | Maximum voltage |
|
|
| `max_i_pos` | Amperes | Maximum positive current |
|
|
| `max_i_neg` | Amperes | Maximum negative current |
|
|
| | Amperes | Output current control |
|
|
|
|
Example: set the maximum voltage of channel 0 to 1.5 V.
|
|
```
|
|
pwm 0 max_v 1.5
|
|
```
|
|
|
|
### Open-loop mode
|
|
|
|
To manually control TEC output current, omit the limit parameter of
|
|
the `pwm` command. Doing so will disengage the PID control for that
|
|
channel.
|
|
|
|
Example: set output current of channel 0 to 0 A.
|
|
```
|
|
pwm 0 0
|
|
```
|
|
|
|
## PID-stabilized temperature control
|
|
|
|
Set the target temperature of channel 0 to 20 degrees celsius:
|
|
```
|
|
pid 0 target 20
|
|
```
|
|
|
|
Enter closed-loop mode by switching control of the TEC output current
|
|
of channel 0 to the PID algorithm:
|
|
```
|
|
pwm 0 pid
|
|
```
|
|
|
|
## LED indicators
|
|
|
|
| Name | Color | Meaning |
|
|
| --- | :---: | --- |
|
|
| L1 | Red | Firmware initializing |
|
|
| L3 | Green | Closed-loop mode (PID engaged) |
|
|
| L4 | Green | Firmware busy |
|
|
|
|
## Reports
|
|
|
|
Use the bare `report` command to obtain a single report. Enable
|
|
continuous reporting with `report mode on`. Reports are JSON objects
|
|
with the following keys.
|
|
|
|
| Key | Unit | Description |
|
|
| --- | :---: | --- |
|
|
| `channel` | Integer | Channel `0`, or `1` |
|
|
| `time` | Milliseconds | Temperature measurement time |
|
|
| `adc` | Volts | AD7172 input |
|
|
| `sens` | Ohms | Thermistor resistance derived from `adc` |
|
|
| `temperature` | Degrees Celsius | Steinhart-Hart conversion result derived from `sens` |
|
|
| `pid_engaged` | Boolean | `true` if in closed-loop mode |
|
|
| `i_set` | Amperes | TEC output current |
|
|
| `vref` | Volts | MAX1968 VREF (1.5 V) |
|
|
| `dac_value` | Volts | AD5680 output derived from `i_set` |
|
|
| `dac_feedback` | Volts | ADC measurement of the AD5680 output |
|
|
| `i_tec` | Volts | MAX1968 TEC current monitor |
|
|
| `tec_i` | Amperes | TEC output current feedback derived from `i_tec` |
|
|
| `tec_u_meas` | Volts | Measurement of the voltage across the TEC |
|
|
| `pid_output` | Amperes | PID control output |
|