# Changeset 14274 for firmware

Ignore:
Timestamp:
Jul 18, 2012, 11:23:20 AM (7 years ago)
Message:
shutter controller docs: adding description of the cabling
Location:
firmware/ShutterController/docs
Files:
 r14273 \section{\label{sec:1} System overview} The new remotely controllable shutter system for the FACT telescope is built around two low voltage 24~V linear actuators from Linak\footnote{Linak AG} driven by two VHN-5019 motor driver which are controlled by an Arduino Ethernet micro controller board. The new remotely controllable shutter system for the FACT telescope is built around two LA23 low voltage 24~V linear actuators from Linak\footnote{Linak AG} driven by two VHN-5019 motor driver which are controlled by an Arduino Ethernet micro controller board. The Arduino is an open-source electronics prototyping platform based on the ATmega AVR micro-controller line. We chose the {\bf Arduino Ethernet} model which mounts a ATmega328 micro-controller with has 32 KB of ROM  and 2 KB of SRAM and already includes a 10 Mbit ethernet interface (WizNet W5100 chipset). The two linear actuators are fixed on a modified of the T-shaped cable support plates and on a L-shaped support which is shrewd to the lid. The T and L-shaped supports are made in blue anodized aluminum and are shown in Fig.\ref{figShutterPhoto}. \begin{figure}[b!] \centering \includegraphics[width=0.49\textwidth]{shutter_photo1.jpg} \includegraphics[width=0.49\textwidth]{shutter_photo2.jpg} \caption{\label{figShutterPhoto} {Photograph of the installed shutter motor}} \end{figure} The Arduino is an open-source electronics prototyping platform based on the ATmega AVR micro-controller line. We chose the {\bf Arduino Ethernet} model which mounts a ATmega328 micro-controller with has 32 KB of ROM  and 2 KB of SRAM and it already includes a 10 Mbit ethernet interface using a WizNet W5100 chipset. The Arduino boards feature a bus like structure on the sides where composed by two lines of pass through connectors where  Arduino compatible boars (shields) can be plugged in. Arduino shields are normally stackable \subsection{Possible upgrades} The pin 4 and pin 9 Arduino I/O port were also connected to lemo cable in case - for example - of future wire coupling with other subsystems (i.e. the interlock system) \clearpage \section{Cabling and connection} The LA23 actuators requires 5 electrical connection as shown in Fig.\ref{figLA23connector}: \begin{itemize} \item$2\times$ AWG20 wires for the powering of the motor; \item$3\times$ AWG24 wires for the powering and the output signal of the Hall potentiometer sensor. \end{itemize} \begin{figure}[h!] \centering \includegraphics[width=0.5\textwidth]{LA23_connector.jpg} \caption{\label{figLA23connector} {Connection diagram for the Linak LA 23 actuator}} \end{figure} \section{Appearance} The linear actuators are provided by Linak with a custom proprietary cable fitted with sealed connector which contains a total of $8\times$ AWG20/24 wires of which only 5 are used from the LA23 actuators. The maximal cable length is 5~m and the provided cable is not shielded. For this reason we reduced the custom cable length to the minimum (about 70~cm) and we used 35~m of UV-resistent shielded cable instead to reach the control electronics. %The patch connector is a In view on the PWM operation, the unused wires of the actuator cable were connected to ground with the goal of reducing the noise on the Hall potentiometer and current sensing measurement. \begin{figure}[h!] \centering \includegraphics[width=0.9\textwidth]{LA23_cable.pdf} \caption{\label{figLA23cable} {Cable specifications for the Linak actuators}} \end{figure} %\section{Diagram of the filter board} %\section{Logic Block of the firmware} \clearpage %\section{The preliminary web interface} \begin{thebibliography}{50}