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Industrial Rumbler Controller


#1

My regular day job is working for an engineering company where I laser cut and fold sheet metal. The big boss of the company is rebuilding a rumbler machine to clean small parts with.

During some conversation about the rebuild the boss floated the idea of a control panel to make operating the machine fully automatic, but the idea was shot down due to the price of industrial control PLCs and having it designed and built.

I done some costings and came up with an AU$500 figure to build a control panel based on a Panda. I pitched the idea to the boss and he went for it.

So over the next few weeks I’ll post a build-log of what I am doing along with diagrams and photos of the build.


#2

Sounds interesting Heffo
Great to have some projects in here that has some practical use and is not just a test / driver assembly.


#3

Here is a block diagram of the control panel system.

The system is all centered around a FEZ Panda.

There is a 16x2 LCD display for status and configuration of the machine. It is equipped with an I2C backpack to simplify connection to the panda.

There are 7 panel LEDs as status indicators to show machine functions (Pump On, Fault, Power, etc)

There is some discreet 74 series logic (2 AND gates and an XOR gate) acting as a safety to disable both 3-Phase relays if a software or hardware error attempts to enable both forward and reverse relays at the same time, avoiding the shorting of two of the phases together.

All of the relays and both the thermal overload breaker and over-current circuit breaker report their states back to the FEZ to allow it to detect any fault with the system. (Breaker tripped, relay not engaged, etc)

There is a 6-button keypad (U,D,L,R, Tick & Cross) and cycle start & stop buttons, Also an emergency stop button on the power to the relay coils (not indicated in block diagram) to shut-off the pump and motor if there is an emergency.

I have started on the schematic and major component procurement phase of the project, also started taking some photos for a wiki page.

Expect more details soon.


#4

As an extra note, here is a schematic of the relay safety logic. It’s pretty easy to follow.

The two AND gates on the left act as buffers.

The XOR gate in the center only goes high when ONE of it’s inputs is High. If both inputs are High or Low, then the Output is Low.

The two AND gates on the right only go High when the enable line for that gate, and the XOR gate are both High aswell.

Truth Table:


FWD_EN	REV_EN	FWD	REV
------------------------------
Low	Low	Low	Low
High	Low	High	Low
Low	High	Low	High
High	High	Low	Low


#5

thank you for this useful information.
I like your project.