# I want to synchronize two identical rice filling machines to fill bags alternately

#### billal

Joined Aug 21, 2015
3
I am currently working in a rice processing facility for a university project. they have two identical rice filling machines that are semi manually operated and the output of both these machines converge onto a single line after one or two processes which have constant processing times.
The trouble is that they want to automate the line (apart from the filling machines) so they do not want the bags from the filling machines to be converging simultaneously, currently a worker is stationed at the converging place to sort them and create space between bags.
If the machines could be synchronised to fill bags such that when machine1 is filling the bag machine 2 is not and vice versa then bags would automatically appear alternately on the converging point, hence eliminating the need for the worker.
Here's how the machines work.
There's a hopper on the top. a turntable rotates such that 8 "cups" on it move and stop under the hopper one by one and get filled. and at the same time the cups are also stopping over the pipe that leads down where a worker places the bag to be filled, then as the cup moves on the worker passes the bag to another worker, takes another empty bag and places it under the pipe before the next cup empties in it. The speed of the machine is not customizable and they do not want to either. The stopping mechanism is such that a metallic "square" rotates with the turn table in front of what seems to be an optical sensor. When the side of the square is perpendicular to the sensor/laser, it stops for one second then rotates till the next side is perpendicular. I believe it is based on reflection and a timer.
How can we if its possible use these same sensors to alternate the pattern of the two identical machines. Note also that workers tend to switch of the machines for a few seconds if they get tired or they mis-pick an empty bag. The logic should be such that even if one machine is stopped the other continues to function normally, and when the machine rsumes function it will continue to be synchronous(alternately).

(PS. I am a have little to zero knowledge about electronic circuits, plcs, microcontrollers, so please try to use as much layman language as possible.)

Joined Jul 18, 2013
28,528
I see the easiest way would be to implement the logic control of the machines with a PLC, once the various sensors are input, the logic can be fine tuned to the sequence you need.
Max.

#### Kermit2

Joined Feb 5, 2010
4,162
If you plan on getting useful information from us based on the limited description you have given the you MUST have more knowledge than you confess to have. It is like asking a surgeon to tell you how to perform an operation and telling him to not use any 'fancy' medical type words.
To give a person with limited knowledge that advice you need will require us to have a huge amount of information about your equipment which we do not have and cannot guess. Lots of pictures and many more checks of connections and a long dialog where you answer lots of additional questions will be required.
Right now I would GUESS that it will be easy to do with some common limit switches and custom actuator paddles to press them, but I cannot tell you where to put them or what wires they need to connect to with out that additional information you must supply.

#### billal

Joined Aug 21, 2015
3
I understand this issue of me not being able to provide enough information for you guys to make proper suggestions also considering my lack of understanding. In a day or two i will be able to post a video of how it works and possibly the electronics. Would that help?
And thanks anyway for the answering.

#### Kermit2

Joined Feb 5, 2010
4,162
That would be a wonderful start

Joined Jul 18, 2013
28,528
(PS. I am a have little to zero knowledge about electronic circuits, plcs, microcontrollers, so please try to use as much layman language as possible.)
With this admission I wonder how you aim to complete a project such as this, that normally requires some knowledge or expertise in control logic?.
Unless it is a absolutely very basic problem, I don't see alot of chance of solving it remotely.
Max.

#### GopherT

Joined Nov 23, 2012
8,009
Power 1 filling valve with a PNP (or p-channel mosfet) and the other machine from an NPN or n-channel mosfet. Then have some sensor on the line where bags are ejected that triggers a flip-flop circuit.

The flip flop switches from high to low, every time it is triggered (every time a bag exits). That way, the PNP-powered valve will activate when the flip-flop is low, and the NPN-powered valve will activate when the flipflop is high.

If you want to put it all on a timer instead of using a sensor, you can do that too but with more risk. Because it will keep filling / switching even if a bag does not come out to trigger the sensor.