The overall goal is to manufacture alveoli made with carbon plates. These are baked with heaters in an oven.

First, the first layer of carbon material has to be cut and put around the inner mandrels. This material has to be preheated up to 80°C to 90°c for 1h to make the epoxy glue become fluid.

As a next step, the second carbon layer is attached and the combined product is heated up with 2°C/minute (according to the manufacture: 1-4°C/minute is within spec) until 120°C is reached. This temperature is hold steady for 3h, after which all heating power is switched off.

After a cool down process of several hours the mould is dismantled and the baked carbon part taken out.

The elements to control are:

• the air temperature in the oven
• the heating power of the four tube heaters

The slowcontrol for this mould consists of

• 4x K-type temperature sensors inside the tube heaters
• 5x 1Wire Digital temperature sensors, plugged into the mould
• 5x K-Type temperature sensors plugged into the mould and mandrels
• 4x 230V 400W power dimmers
• a simple bi-metal over-temperature switch off
• a micro controller reading out all 1 Wire sensors and send the data to the computer,
• a computer, running a control loop and a display/web interface for the readings.

All sensor information is read out and send via MQTT to the central computer, which also runs the control loop for the set temperature. The final decision on the heating power is then send to the dimmers.

Software used for this project:

• on the computer: https://gitlab.rlp.net/pbotte/compact-slowcontrol/tree/mqtt
• on the micro controller: https://github.com/peterotte/HPCSlowControl

Eltako FUD 14 dimmers (in total 4 of them) are used to control the heating power of the heating tubes.

Manuals:

• oven_voetsch_omh_100_manual.pdf
• oven_voetsch_omh_100_technical_description.pdf
• Manual for our oven
• 

• heater: ISI 321, 25D330 230V 125W (attached information)
• cold zone: 7-10mm on one end - 15-20mm on the other end
• Have a k-type sensor included, see section below.

• Manuals: tube_heaters_datasheet_4_.pdf
• Technical details: details_heaters.pdf

• https://www.adafruit.com/product/642
• Three wires:
  • On connector side: Orange Stripe connects to 3-5V, White connects to ground and Blue Stripe is data.
  • Wire colour after connectors: Ground → white, plus –> red, data → brown

• 1-Wire Thermocouple K-Type Electronics
  • Adafruit Note: Works fine, but one has to solder some parts
  • Seeed Note: Works as fine as the Adafruit ones, but without soldering.
• K-Type sensors:
  • From Adafruit
  • From Seeed

• Web-Interface: http://mould-control.emp.him.uni-mainz.de/
  • Get temperature and dimmer readings
  • Control the dimmers.

• Full Access via SSH:
  • ssh pi@mould-control.emp.him.uni-mainz.de with raspberry as password

Install docker on the pi via:

wget -O install_docker.sh get.docker.com
sudo sh install_docker.sh 
sudo usermod -aG docker pi

and logout and login again.

Next, create an volume to permanently store data and run

docker volume create --name node_red_user_data
docker run -d -p 1880:1880 --restart unless-stopped -v node_red_user_data:/data  --name nodered nodered/node-red

Open the webpage: http://localhost:1880 and install via the menu further packages like node-red-dashboard to build a GUI.

Source code:

• 21.7.2020: * Selector for Heaters added
• 13.7.2020: Displayed State Names changed
• 17.6.2020: flows.json.zip
• 22.6.2020
• 25.6.2020 with multiplug

• with this device:
  • USB Analog Output Module / USB DAC 0-10V 4-20mA – 4 Channels
  • from Lucid Control: https://www.lucid-control.com/product/lucidcontrol-ao4-4-channel-analog-output-usb-module/
  • Manual: user-manual-lucidcontrol-ao4.pdf
• The oven is plugged into this multi plug:
• Premium-Web-Line V3 Internet-Steckdosenleiste (4-fach Steckerleiste in 19" mit Master-Slave Funktion, LAN-Anschluss, 3m Kabel, Made in Germany)

To set and get info from the Brennstuhl multiplug (IP address 10.106.11.21) run the following commands:

Copy the MIB file into ~/.snmp/mibs/nbs.mib . In case an error is stated, change ws_brs to wsbrs in the mib file. The use the MIB file, add

  -m ALL

to all your commands. BUT note: the mib file seems to be a bit buggy. To get the ISO numbers, eg add -m none.

Perform a complete walk of all parameters

snmpwalk -c public -v 2c 10.106.11.21 1.3.6.1.4.1.40595.1

Get the status of the first outlet

snmpget -c public -v 2c 10.106.11.21 iso.3.6.1.4.1.40595.1.1.1.0

and 2nd outlet

snmpget -c public -v 2c 10.106.11.21 iso.3.6.1.4.1.40595.1.1.2.0

Set the 2nd outlet on

snmpset -c private -v 2c 10.106.11.21 iso.3.6.1.4.1.40595.1.1.2.0 u 1

and off

snmpset -c private -v 2c 10.106.11.21 iso.3.6.1.4.1.40595.1.1.2.0 u 0