Motor controller and limit switches

NeilRogers

I am helping on a project. There is a track that has a carriage that is moved by a 90volt dc motor, would like it to be variable speed.

There are 6- 48 volt actuators that are triggered based on reed switches, as it passes by.

I know how to solder, and have built similar items before, but want to ask the experts how they would tackle this, and what parts to buy to get started. Only 6 inputs needed.

Outputs based on 6 actuators and motor controller.

kwinn

The more detail you provide the better the chance of getting help. What parts do you have now and what is the purpose of all this?

NeilRogers

Greenhouse flower basket sprayer system had a controller that keep breaking.

It goes down the length of the green house, as it passes zones, reed switches trigger the zone changes,

I was looking at going with an Allan Bradley micro controller, but if I can prove this is a better option, I will switch.

So far we have the 90volt motor and the reed switches. And think the 24volt supply from the old system.

We have no controllers yet. So we have flexibility on what we get, just need assistance on the best option.

One thing to keep in mind, we may replace more lanes with this system, if it works good. A controller per lane, they ride on the carriage that goes the length of the lane.

erco

90 vdc is unusual. Obviously not jibing with your 24v supply. See http://forums.parallax.com/showthread.php/149892-Aquarius-The-Greenhouse-Watering-Robot?highlight=greenhouse+robot

NeilRogers

24 volt to control the sprayers, 90 volt dc for the motor to move the carriage.

That example is not practical because the carriage needs to be overhead to spray, because of how many plants are growing, on multiple levels. Also, there is no floor space to walk, let alone drive that big thing.

NeilRogers

Any suggestions?

Would like to order parts this week or go a different direction if there is no one that knows,

Would just an I/o board work, or do I need a card to drive it?

jdolecki

Look up automation direct u can get a plc for 99 bucks. software free

xanadu

Pictures may be the only way to show anyone what you're describing. With a weak understanding of what you have going on, there isn't much advice to give.

I guarantee that if you use a microcontroller such as the Parallax BS2 or Propeller you get support for it here or through the support phone/email system.

Hal Albach

I'm trying to figure out what you mean by 'zone changes'. Is the carriage supposed to change speed in various zones or do you need to activate / deactivate various actuators? You mentioned 6 inputs, do you also need 6 outputs? You indicated that you would like the 90 Volt motor to be variable speed so you will need a very robust PWM circuit.
As for a controller, for the same price as a Basic Stamp 2 you can purchase a Propeller Activity Board with vastly more resources and support.
For the actuators probably a relay board will suffice, I've never done high power PWM before, I'm sure someone here can help with that.

kwinn

A 90V DC motor can be run from 1/2 wave rectified 120VAC and speed controlled by an SCR. As xanadu says a picture (or block diagram) of what you are trying to do would be a great help. I think the propeller would be a good choice for this.

NeilRogers

So i am looking at the Activity board or the Professional board, both look like good options, for $50 more, and extra prototyping options, seems like the way to go.

Found this: http://www. elecfreaks. com/store/8-channel-5v-relay-module-p-268.html 8 relays, 24 V option, for $17.

Looking for a SCR option. anyone have any recommendations for a 90V DC capable one? i did a little searching and nothing that i like so far.

And no, i have not made a diagram yet. next on the list. thanks for the suggestions, if i get an answer on the SCR i will order it all today.

Neil

Duane Degn

The Propeller may not be able to drive that particular relay board without some sort of level shifter. If you removed the LED and/or used a lower resistor value on the signal line, it would probably work with the Prop. You can certainly control relays with a Prop but it often requires a slightly modifying a circuit intended for 5V logic.

NeilRogers

ok, that is good to know!

With the propeller activity board and the 5V breadboard, would that be good enough to run the relays... ok editing my comment...

actually thinking a capacitor to increase amps, or use two lines, from the activity board. just spitballing. that one says it is Arduino compatible, isn't that board going to be discontinued?

Hal Albach

Just looked at the schematic for the 8 relay board. Each of the eight inputs goes to a PNP transistor through a 1 K resistor, requires logic 0 to turn the relay on. The web site has a Wiki page link to a much different single relay board. That one's inputs go through a LED to an optoisolator and requires a logic 1 input. The 8 relay board should work just fine with the Propeller Activity Board, maybe include a 10-20K pullup to +5 to insure the input transistor stays cut off when the prop pin is high.
As for the 90 Volt motor, without knowing the current draw it would be difficult to reliably fit an SCR. Also wondering about just how much speed control Neil needs with that motor.

Neil, the Arduino compatable board you linked to is an Arduino shield, meaning you have to provide the Arduino controller for it to work. The Prop Activity board comes with the propeller chip, voltage regulators, and some other goodies. It even provides Xbee connectors so that you can operate this thing remotely.

kwinn

There are no DC SCR's. The suggestion to use an SCR was based on using 1/2 wave rectified 120VAC. Whether or not this is possible depends on the type of DC motor you have, and you have posted very little information so it is difficult to give any specific help.