Fishtank (5)

Article no. 5 about the fishtank, Januari, 2020.  

In this article 2 different subjects, the system architecture and event logging.


Previous publications:
Fishtank (4), the instrumentation, Nov 2019
Fishtank (3), level simulation, Oct 2019
Fishtank (2), the motor valves, Sep 2019
Fishtank (1), starting a control for a sea fishtank, Aug 2019


The complete architecture

All functions of the sea reef microcontroller are now programmed and it is time to present the planned architecture. For the coming period i will be busy with the hardware of the installation; e.g. the panel for the DUE controller and other components. Working with salt water will require an "industrial" setup. The first pvc parts are ordered yet; pvc 1/2" piping, connections and pvc tee's. Also the first drawings for the tank and the sump are made in order to buy the first parts. I'll keep a photo log for the actual realisation of the tanks. 

Below a picture of the current architecture:

Architecture Fish tank

All parts and functions will be described in the manual for the fishtank. Someday, i will make a zip with all relevant information. 


Eventlogging (HMI/text messages)

Last period i worked on the event logging and alarms. The HMI is extended with an alarm list. Also added a Sim800L, GSM Modem to the system. Alarm messages are send to my personal phone by SMS messages. See also the picture below:

Poseidon 3.0 picture


In the lower part of the HMI screen is a list box with the alarms. Time/date, severity and alarm text are presented. A maximum of 100 messages are stored in this first in, first out buffer. The buffer is kept encrypted in the DUE memory. When HMI is started, the actual buffer is send to HMI and presented on the screen.  

Serious events (alarms) are also send by a text message to my personal phone. The Sim800L is working with a pre-paid SIM card, so i have to check the credit of the pre-paid card. A sim card with a credit of zero, is not very usefull (!). Every 6 hours, the credit is checked by sending a (free) message to the provider to check the credit amount. When this informational message is received by the modem, a check is done on certain text strings to obtain the credit amount. The amount of credit is used to determine the severity. Under a certain amount, it will be handled as an alarm. In the above example, the credit amount will generate an alarm when it is under 20 euro (done for testing, the alarm level will be less 5 euro).

Another extra possibility is to send a sms from my personal phone, with text "STATUS". When received, the controller will send a message with the actual status and the most important data, back to my personal phone. See the picture below (sorry, text is in dutch language). 



Remark on the sim800L modem; i had trouble getting the modem to connect to the mobile network. Main reason was the cabling; the "standard" breadboard cabling is just not thick enough to power the sim900L during startup. It needs about 2 Amp's during startup. So i had to install other wiring and a stable powersupply.