Basic Stamp protection , please help.

markuster

Hi,

I have installed some Basic Stamps near 110 Volts AC motors.
The motors have contactors , switches , and each time the contactors work
the Basic Stamps reset. Even , the B.Stamps stop working.

I bought a better power supply but I have the same problem yet. Even I
used batteries as a power supply , and I have the problem yet.

I used the Basic Stamp without the motors and contactors and the B.Stamps works fine.

Do you know how can I protect the B. Stamp. from contactors or switches or motors ?

I have read something about and there are some networtks called snubber.

Thanks, Mark

Leon

Transient voltage suppressors, such as AVX TransGuards, can be very effective.

Mike Green

You also have to be careful of wiring connected to the Stamp and its power supply, especially if the high power AC travels near the Stamp's wiring. In that case, you may need to use shielded cables for the connections to the Stamp and to enclose the Stamp and its power source inside a shielded box of some sort.. You may need ferrite cores on the power supply wiring to the Stamp. A lot depends on the details of your Stamp setup, where the wiring runs, where the Stamp is relative to the high power wiring. General advice, while good, may not be adequate for your situation. If you provide details of your situation, we can offer more specific suggestions.

markuster

Hi ,

You can see the attached. I am using the attached to turn
on and off the motors

You can see that it is insolated .

Thanks, Mark

Mike Green

That's nice that there's insulation and the logic side of the circuit has an optoisolator and a relay between the Stamp and the motor, but it's not working the way you expect so there's something about your setup that's not shown in the schematic. I suggest that you're not showing the parasitic capacitances, inductances, and the parasitic transformers between the high power side of the circuit and the low power side. You have to get a handle on those because the logic side is sensitive and it doesn't take much energy coupled into the logic side to cause problems. As I mentioned, you may need to shield the logic side of things including the power source for the logic. You may need to physically separate the logic wiring and the related power wiring from the motor and its wiring. Without a description of the physical layout, it's impossible to suggest anything more specific.

Chris Savage

Long leads to/from each device can cause issues, especially if the high voltages wires are in proximity to the control signals from the BASIC Stamp. Essentially the radiated EMI can cause problems on the low voltage BASIC Stamp signals. When controlling high voltage and/or inductive devices you need to not only isolate the control/load signals, but keep the wires away or shielded. For example the power leads if longer than 1 foot may need to be inside grounded metal conduit. The BASIC Stamp control board may need to be inside a grounded metal enclosure.

markuster

Hi,

Here I am sending more information about it. Please see attached pictures.

You can see that all is insolated.

I can't find the problem.

Each time motor starts , the Basic Stamp resets.

sam_sam_sam

Do you know how can I protect the B. Stamp. from contactors or switches or motors ?


Are you using a optic sensor on all of your switches to the Basic Stamp if you are not you should also are you using a switching power supply to power your Basic Stamp check to ripple current you have you may need to add a filtering cap to it also power all your optic sensor form the same power supply


The LED side of the optic sensor should be powered fom the Basic Stamp power supply and the other side should power from some where else
and the ( ground or - ) should not be shared


I once had this problem my self and this was how I fix it

markuster

Hi Mike , Sam and Chris ,

I don't understand how can avoid parasitic capacitances, inductances, and parasitic transformers.

Do you know how can I protect my stamp from them ?
Do you need more information about my proyect?

Thanks, Mark
PS: For me it is very important to use a Basic Stamp for industrial purpose.

Mike Green

As we've said before, you need to shield the logic circuitry and its wiring. You need to physically separate, even by an inch or two, the wiring that's carrying power from wiring that's carrying logic signals and power to the logic. In your last diagram, you show 24V going to the BS2 circuitry. I hope that there's something that's reducing that voltage before it's applied to the Stamp. You may need some filtering on the 24V power supply.

Without much more detailed schematics, parts descriptions, and photographs, it's really impossible to give more specific recommendations.

The problem you're having is something that's common in any situation where you have logic circuitry (of any kind) controlling high power devices. It's an issue for appliances like microwave ovens, toasters, food processors, etc.

stamptrol

Try to show us the complete circuit diagram.

There's something not being shown to cause the problem you're seeing. Many of my projects have worked fine with 120 VAC and the Stamp mounted on the same circuit board.

In your isolation circuit, there are a couple of things that cause concern:

- three separate power sources are noted: 5v, 12 v and 110 volts but nothing is shown as to how they interconnect. Are they all separate? Is the DC negative supposed to be common?
- the 2n3904 transistor is shown in an odd connection so that there is great risk that the base voltage will be very low when the i/o pin is trying to drive it due to the combined voltage of the opto and the LED. More normally, the npn transistor would have its emitter at 0V. This wouldn't explain the Stamp resetting but it would explain the circuit acting strangely as far as the relay operating sometimes and not others.
- the diagram of the Stamp connected to 24 volts and the motor drive are also quite scary as shown.

Cheers,

markuster

Hi Mike , Sam , Leon and Chris :

Here is attached a better picture.

I have the same problem yet , the B.Stamp is reseting when I send a HIGH to start the motor from the B. Stamp .
( I have used 3 stamps and all of them have the same problem)

The power supply is an industrial power supply that brings 24 Volts DC then I add a regulator to have 12 volts.
These 12 volts I am using to power the B.stamp.
The power supply is supplying the B.Stamp only.

Please if you need more information only ask me.

Thanks, Mark

Chris Savage

Something doesn't look right in your schematic...is that a Variable Frequency Drive? If so, do you have a datasheet or make/model information for it? Your schematic seems overly complex for what you're trying to do.

Mike Green

There is nothing in the schematic that would explain why the Stamp resets. There must be some coupling between the motor itself and the control electronics or between the motor and the 24V power supply or between the motor and the wiring, whether power wiring or ground wiring ... something. You have two optocouplers involved, one in the solid state relay and one in the optocoupler (I don't know why you have the optocoupler). Most solid state relays can be turned on with a 5V signal at 20mA or less and can be driven directly from a Stamp I/O pin.

As I've said several times before, you're going to have to shield the Stamp and any attached logic and power source. You may also need additional filtering on the 12V regulator (which you haven't shown) that feeds the Stamp. Tom Sisk (stamptrol) and others have used Stamps successfully in high power situations. It's not the Stamp. Either the motor is causing noise spikes or it's loading down the power supply input sufficiently to cause the power to drop out. Noise spikes can be coupled into ground wiring, power supply wiring, or the connection from the I/O pin. You can either use an oscilloscope to try to track this down or you can just heavily shield and filter everything.