Daisy Chain PLC

Hi All,

I have the following requirement:

For simplicity lets take a Pair of motors, each motor has control box attached to it, with forward/reverse push button and a ALL/Single selector switch.

When Selector in Single position For/Rev will control only that motor where operator is standing and pressing the buttons.

When the Selector is in ALL position, both motors will go forward if For button is pressed and so on,


Then if our client want to purchase 2, 4 , 6 or 8 motors, they have to connect the communictaion cable to one of the boxes and daisy chain them, Now All selector will move ALL the motors together.

The communication must share information about encoders on each motor with the other control boxes , to keep the parameters like speed sincronized.

Each box must contain some type of smart/programmable control board similar to PLC in functionality, but it should look like a board, must be aible to form a network of similar boards and
share information between them.

I have a feeling that it is a common situation, but don't know where to start.

I've seen models from competitors that do just what i described.

And price should be very low.

Thanks

It seems very simple.
If you use something like AB ML1400/1100.You have stand alone PLC for each unit and you can share info between them.
With Ethernet you can get almost any distance.
If you need synchronize speed (Master Slave 1,Slave 2,.....)
You need network like Profibus of Profinet.
Give us more detailed (like how fast your encoder)we will give you specific answer.

What is this machine? Are you talking about adding more multiple motors on one machine or adding more machines?

Dan Bentler

Thank you for your time,

In more detail, the motor is part of power unit for hidrolic lifter, to expand the existing setup , for example 4 power unit, the client must be able to buy a pair of power units and
the 6 power units must recongnize each other an move up/down together or 2 at a time , dpending on operator selection, that could be done from any of the six control boxes, the operator will go to nearest box and press up or down button.

For example the first 4 control boxes have 4 plcs that work together, (who is master and who is slave??) they all have the same irarchy, now when new pair (it is alwasys in pair), of plcs connected to the existing network, no modification must be done, on any of the PLCs, the have to recongnize the new
pair automatically. Is this possible with PLCs?

I'm familiar with micrologix 1000 and Siemens s7-200, but not in network environment.

Regards,

I think if you use PLC with Profibus or profinet and you program it for the max option.
every time you will add unit it will work together with the 1st unit which is the PLC(other units is remote IO.)
If you need every unit will be stand alone .I think it can be done,maybe more complicated.
Give us more details.