Searching \ for 'Problem' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=problem
Search entire site for: 'Problem'.

Truncated match.
PICList Thread
'Problem'
1996\11\21@094244 by Harry Tenopoulos

flavicon
face
Hello everybody

I have designed a PCB for the company i work for which is used on an
automatic machine..
The board has 3 PICs on it (2 16C54 and 1 16C55)

This board interfaces with 3 external power relays.These relays are
signaled from 3 other reed relays on the board which are
opto-isolated from the signaling PIC.

When the power relays operate alone (not connected to the machine's
motor) there is no problem. But when they are connected problems
start. These three relays control a two speed bi-directional  220V
motor. At the change of speed or direction the electronic circuit
seems to be reset (it happens about once in 10 changes).

Can anyone tell me what is happening ?


Harry

1996\11\21@103521 by Shawn Ellis

flavicon
face
At 04:40 AM 11/21/96 +0000, you wrote:
{Quote hidden}

RF spikes... Ran into the same thing with a opto-isolated Traic running a UV
Lamp ballast.  The solution was a RF capacitor between the ballast's output
wires.  Also, the spikes might be coming through the AC line, try running
the Motor on a separate AC circuit from the PIC (different outlet).  If this
is the fix, then you probably need an AC filter between the motor and line
(RC filter mabye).

1996\11\21@143914 by ernhard Schweighofer

flavicon
picon face
On Thu, 21 Nov 1996, Harry Tenopoulos wrote:
> Hello everybody
>
> I have designed a PCB for the company i work for which is used on an
> automatic machine..
> The board has 3 PICs on it (2 16C54 and 1 16C55)
>
> This board interfaces with 3 external power relays.These relays are
> signaled from 3 other reed relays on the board which are
> opto-isolated from the signaling PIC.
>
> When the power relays operate alone (not connected to the machine's
> motor) there is no problem. But when they are connected problems
> start. These three relays control a two speed bi-directional  220V
> motor. At the change of speed or direction the electronic circuit
> seems to be reset (it happens about once in 10 changes).
>
> Can anyone tell me what is happening ?


Maybe your Supply voltage (for the electronic circuit) breaks down
('Spannungseinbruch') --> Can you use a oscilloscope to check it out ?

bernhard

>
>
> Harry
>

Bernhard Schweighofer alias spam_OUTschweigiTakeThisOuTspamsbox.tu-graz.ac.at
(Student at Graz University of Technology, Austria)

1996\11\21@224416 by Larry Griffin

flavicon
face
It was written:
>I have designed a PCB [...]
>This board interfaces with 3 external power relays.These relays are
>signaled from 3 other reed relays on the board which are
>opto-isolated from the signaling PIC.
>When the power relays operate alone (not connected to the machine's
>motor) there is no problem. But when they are connected problems
>start. These three relays control a two speed bi-directional  220V
>motor. At the change of speed or direction the electronic circuit
>seems to be reset (it happens about once in 10 changes).

I'm assume you are powering the PIC circuitry from the same 220VAC source
(or one leg of it).  It sounds like you are getting transient voltage
spikes through the AC supply.  Add 3 MOVs.  Ideally they should be
installed as close to the motor relays as possible, but may be installed
just ahead of the PIC power supply.  One MOV should connect across the two
AC lines.  The other two should connect between each AC line and ground.

You've apparently done a good job of isolating the outputs, but spikes
coming through an AC supply can be several thousands of volts and cause
some really nasty problems!  Let me know if you need any more assistance.

Larry Griffin
Southwest Technical Arts - http://www.swta.com

1996\11\21@234755 by Bob Blick
picon face
Harry writes:

>When the power relays operate alone (not connected to the machine's
>motor) there is no problem. But when they are connected problems
>start. These three relays control a two speed bi-directional  220V
>motor. At the change of speed or direction the electronic circuit
>seems to be reset (it happens about once in 10 changes).
>
Harry,

Look for ways that the +5 volts is getting hit, either because of drop or
noise or ground current. Quite often noise on the 220 line will make common
mode changes on your +5 power supply. Tie the negative to ground, and put
filter caps across the +5 supply at the board.

Try the "electric drill" test. Take an electric drill and switch it on and
off when it's close, far away, plugged into another outlet, etc, and see if
you get clues. If it passes the test plugged in the same outlet, 10cm away
from the board, then it's passed that test and you're ready for the "tesla
coil" test at 2 meters.

Cheers, Bob

1996\11\22@063036 by ernhard Schweighofer

flavicon
picon face
On Thu, 21 Nov 1996, Larry Griffin wrote:

> It was written:
> [...]
> spikes through the AC supply.  Add 3 MOVs.  Ideally they should be

What's a MOV (something like a capacitor ?)

bernhard.

Bernhard Schweighofer alias .....schweigiKILLspamspam@spam@sbox.tu-graz.ac.at
(Student at Graz University of Technology, Austria)

1996\11\22@093156 by Keith Dowsett

flavicon
face
>On Thu, 21 Nov 1996, Larry Griffin wrote:
>
>> It was written:
>> [...]
>> spikes through the AC supply.  Add 3 MOVs.  Ideally they should be
>
>What's a MOV (something like a capacitor ?)
>
>bernhard.
>
>Bernhard Schweighofer alias schweigispamKILLspamsbox.tu-graz.ac.at
>(Student at Graz University of Technology, Austria)
>
Metal-oxide varistor.  They are used for lightning protection (induced
voltages, not direct strikes) and usually clamp transients at 3 x the supply
voltage. This might not be enough to protect the PIC from motor generated
surges, but they're cheap enough to be worth trying.


Keith.
==========================================================
Keith Dowsett         "Variables won't; constants aren't."

E-mail: .....kdowsettKILLspamspam.....rpms.ac.uk
WWW:    http://kd.rpms.ac.uk/index.html

1996\11\22@120254 by Giles L. Honeycutt

flavicon
face
I have seen this befor in my work, MOVs are a start in the write direction, but
may
not solve the problem.  They will clamp the tops of large spikes, but will not
kill
them.  I recoment using a "ORANGE DROP" cap across the motor. (Oh no, not a cap
accross a relay contact!!)  Don't wory, a .1 - .5 Uf cap will be fine, and if
you look
at the speed of the spikes you are trying to kill, the resistance of the wire is
the R
for snubing them out.  Also, on a AC motor, a spike can be from the positive
peek to
the negative peek and the MOV will never even see it.  The RC will supress such
fast
changes.  Orange drop caps have been used for this for years. Allied Electronics
has
them.   Gook luck.


Harry Tenopoulos wrote:
{Quote hidden}

--

 GiLes L. HoNEYcuTt
 *****************( Lost and confused )*********************
 EraseMEgilesamispam_OUTspamTakeThisOuTix.netcom.com

1996\11\22@195521 by Tony Matthews

flavicon
face
Harry Tenopoulos wrote:
>
> Hello everybody
>
> I have designed a PCB for the company i work for which is used on an
> automatic machine..
> The board has 3 PICs on it (2 16C54 and 1 16C55)
>
> This board interfaces with 3 external power relays.These relays are
> signaled from 3 other reed relays on the board which are
> opto-isolated from the signaling PIC.
>
> When the power relays operate alone (not connected to the machine's
> motor) there is no problem. But when they are connected problems
> start. These three relays control a two speed bi-directional  220V
> motor. At the change of speed or direction the electronic circuit
> seems to be reset (it happens about once in 10 changes).
>
> Can anyone tell me what is happening ?
>
> Harry
hi
Can you not put a scope across the power pins it's best to know what
sort of noise you're being subject to.

1996\11\23@074450 by peter

flavicon
face
Harry Tenopoulos wrote:
{Quote hidden}

I've had similar problems with DC motor control
I have not had time to find the problem yet but I
was very sloppy with earth returns and decoupling

I did find a mention in the pic16c84 data sheet ds30081A
"6.3.3 Operating in a noisy environment" page 32
says that "register contents can get corrupted due to noise
spikes.The on-chip watchdog timer will take care of all situations
involving program sequence "lock-ups." however,if an I/O control
register gets corrupted, "............... you get the idea

My lock-up problem is on a 16c56 but I must assume that the
registers on all the pic's are similar and therefore all
are prone to this problem

--
Peter Cousens
email: peterspamspam_OUTcousens.her.forthnet.gr
snailmail: Peter Cousens, karteros, Heraklion, Crete, 75100, Greece,
phone: + 3081 380534,    +3081 324450   voice/fax

1996\11\24@002508 by Hamilton Feltman

picon face
On Thu, 21 Nov 1996, Harry Tenopoulos wrote:

{Quote hidden}

       I've had an experience almost exactly like yours.  The fix
is to use a solid state relay (zero crossing type) to switch the motor.
You may have to use alot of them depending on your relay configuration (most
SSR's are SPST , using a single Photo-Triac) and make SURE to use a varistor
across the Triac and all motor windings.  Of course the diode as
previously stated on the relay to kill inductive flyback is a good idea.
And a very clean D.C. supply for the logic is necessary, also, but the
real problem has to do with the POSITION of the motor armature when power is
applied or released (It only happens once in a while, i.e. if you apply
current to a motor when it is in its most inductive position AND the
A.C.  is at 90 or 180 degrees you will get a HUGE spike.) Just turn on a
radio and when you cant here a POP in the speaker then you know your there.
       -Hamilton

1996\11\25@063508 by efoc

flavicon
face
Shawn Ellis wrote:
>
> At 01:38 PM 11/22/96 CST, you wrote:
> >     This problem happens a lot. In addition to MOVs across the motor
> >     leads, place MOVs across the power relay coils. Also, you could add a
> >     series RC spike suppression circuit in the same place. Use a 0.22uF
> >     cap rated for X2 service (Digi-key P4612-ND or Panasonic ECQ-U2A224MV)
> >     and a 40 ohm 5 Watt low inductance resistor (carbon comp or low
> >     inductance wirewound). Wire the MOVs and RC circuits as close as
> >     possible to the coils and motor terminals. Keep all leads as short as
> >     possible. Use shielded twisted pair cables when ever possible.
> >
> >     Another idea which may help, is to replace your power relays with
> >     Solid State Relays (SSRs). Most SSRs have built in suppression
> >     circuits. Wire the SSRs as close as possible to the motor.
> >
> >     Joe
> >
> Use a diode across the relay, to prevent the relay from "generating" current
> as the soleniod snaps back from acuation...

Called Back EMF I think :))


--
==================================
= New Ideas come from those who  =
= didn't know it wasn't possible =
==================================

1996\11\25@124239 by peter

flavicon
face
Hamilton Feltman wrote:
{Quote hidden}

Words of caution
when the motor is starting up it may draw many times its rated current
solid state relays will not tolerate higher current for short periods
like mechanical relays

when solid state relays fail, its 99% certain it fails short circuit

solid state relays are rarely used for industrial control of motors
the normal course is mechanical relay or inverter
--
Peter Cousens
email: @spam@peterKILLspamspamcousens.her.forthnet.gr
snailmail: Peter Cousens, karteros, Heraklion, Crete, 75100, Greece,
phone: + 3081 380534,    +3081 324450   voice/fax

1996\11\25@141858 by Marv

flavicon
face
On Thu, 21 Nov 1996, Harry Tenopoulos wrote:

...
>
> When the power relays operate alone (not connected to the machine's
> motor) there is no problem. But when they are connected problems
> start. These three relays control a two speed bi-directional  220V
> motor. At the change of speed or direction the electronic circuit
> seems to be reset (it happens about once in 10 changes).
>

Hi,
 I had similar difficulty using the PIC, a couple of years ago, in an
application with a nasty elecromagnetic environment.  After trying all the
usual fixes, it became apparent that the microprocessor was being reset
directly by the magnetic field.  Shielding the entire board, in a steel box,
or just the micro with a metal band alleviated the problem. A copper strap
over the top of the micro was NOT sufficient in this case; a complete
magnetic circuit around the chip was necessary.

Good Luck,
 Marv

1996\11\26@000810 by Giles L. Honeycutt

flavicon
face
Hey, I just wanted to point out a little known and always good to know point
you mentioned.  Copper and Aluminum are great for some kinds of shielding,
but for Magnetic problems (coils, relays, contractors, motor starters,
generators and such) you CAN'T shield the magnetism, you have to direct it.
You must use a ferrous material, such as iron (preferably something that won't
hold a magnetic charge, like mu-metal) to conduct it around your circuit.
A metal plate over your circuit is good enough in a most cases, and the
thicker the material, the more it will "grab" the magnetism.
 I hope this helps someone..
     Giles L. Honeycutt

Marv wrote:
{Quote hidden}

1996\11\26@082342 by Hamilton Feltman

picon face
peter cousens wrote:
{Quote hidden}

       But the "zero crossing" type of SSR will practically
_eliminate_ the worst inductive spike, which happens when the A.C. is at
its peaks. I actually designed a zero crossing circuit and used a
mechanical
relay and inadvertantly forgot the delay between the time when you
energize
the relay and the actual time that the contacts close (doh!).  Needless
to say there was still a spike but when I switched the relay to an
immediately
swithing TRIAC (opticaly isolated) the spike was virtually eliminated,
as well
as the reseting problem I was having. P.S. Put a giant 1 ohm resistor in
series
with the load and connect a fast digital storage scope across the
resistor and
the voltage you see on the scope will convert almost exactly to current
(minus
the small loss of power that a 1 ohm resistor has on your particular
motor).
Of corse most motors draw more current on startup, but its the Inductive
kick
we are worried about here. Another option is to use In-Rush current
limiters.
       They make some *Huge* SSR's these days, just use one rated at Twice
the motor current and it will be fine. (and I wont say "and dandy" 8^)
       -Hamilton

1996\11\26@211950 by peter

flavicon
face
{Quote hidden}

Last Sunday I was at an olive pressing factory, on starting a
centrifugal filter
380V x3 Phase for the first ten seconds draw 300A per phase at fifteen
secs 200A
at 45 secs about 80A then a timer changed it from star to delta
about 6 mins later it was drawing about 40A
Well pumps are also the same, as are industrial washing machines
spin motors
syncronous motors operating in nonsyncronous mode can easily
draw 10 times the sync current (syncronous motors don't have brushes)
Twice the rated load !! and when they blow closed circuit !!
Try one on your fridge and let me know how you get on
Also try phoning your local lift manufacture and ask them why
they don't use SSR's
ps: I liked the joke about the 0v relay
--
Peter Cousens
email: RemoveMEpeterTakeThisOuTspamcousens.her.forthnet.gr
snailmail: Peter Cousens, karteros, Heraklion, Crete, 75100, Greece,
phone: + 3081 380534,    +3081 324450   voice/fax

1996\11\29@031143 by Hamilton Feltman

picon face
At 10:15 PM 11/26/96 -0800, you wrote:
>>         But the "zero crossing" type of SSR will practically
>> _eliminate_ the worst inductive spike, which happens when the A.C. is at
>> its peaks. I actually designed a zero crossing circuit and used a
>> mechanical relay and inadvertantly forgot the delay between the time
when you
>> energize the relay and the actual time that the contacts close (doh!).
>> Needless to say there was still a spike but when I switched the relay to an
>> immediately swithing TRIAC (opticaly isolated) the spike was virtually
>> eliminated, as well as the reseting problem I was having. P.S. Put a
giant 1  >> ohm resistor in series with the load and connect a fast digital
storage scope >> across the resistor and the voltage you see on the scope
will convert almost >> exactly to current (minus the small loss of power
that a 1 ohm resistor has >> on your particular motor). Of corse most
motors draw more current on startup, >> but its the Inductive kick we are
worried about here. Another option is to  >> use In-Rush current limiters.

{Quote hidden}

       All that I really meant was if you do manage to find an SSR that can
handle the current at startup, it will Drastically reduce the inductive
spike (provided it is the zero crossing type) which is having the
ill-effect of reseting the logic (Pics are especially sensitive to
glitches). For most applications, SSR's are cool!  While I wouldn't try to
run an elevator from a pic, I suppose it could be done with the logic
running on a seperate supply all the way back to the mains, and optically
isolate the power relays (two forms of isolation, why not).  You're right
though,  for every big SSR, there is an equally or bigger motor that draws
even more current on startup as you stated (!)
       Hamilton


'Problem'
2000\05\07@064038 by Ravi Pailoor
flavicon
face
Hi PIClisters,

Below is a copy of the email I received from a student. He needs some
guidance in programming with C for 16C63.
I am unable to help him, since I do not use C. Could anyone of you help
him out ?

Thanks and Regards

Pailoor
-----------------------------------------------------------------------

( i hope you wil read this)

Hello my name is Ron

I have got a real problem.

Currently i am involved in a school project , and things are not going
well at all.
I wil shortly explain:

In the proiect i am responsible for programming a remote controlled
carpet rover.
This rover must follow a certain track.

The data that the car/pic has to deal with is :

2 puls trains  :  The controller must generate two puls trains at the
same time.
                      These puls trains are connected to 2 servo motors
, they control the speed and direction of the rotation.
.
                      These two puls trains must be the same if  the
car is on the track.
                      The two puls trains must variate when the car is
getting of  the track, servo left or right has to run faster to
                      correct.

                      The servo has some specifications, the controller
must generate a puls train with a :
                      puls ontime (high)  from min 1 ms - max 2ms
                      puls of time (low)   from min 5 ms - max 20ms

3 input lines:    These 3 lines come from the tracking kit (3 TLL ) they

                      represent the led-status of the tracker (111
rover/tracker on the
                      track 000 rover/tracker of track)

It is essential that the program generates two trainpulses at once (so
the car dives straight on ) , and in the meanwhile reads the status of
the
leds and takes action on it by changing the pulson/of time of the
pulstrains.

1 USART: sending/receiving data


We chose  the PIC 16c63 to proces the data ( it has got 3timers, 2pwm
modules, 18i/o quite enouch is think, and usart)

The thing is that at our school we mainly used c++ to write programs.
I wrote the program already, but this is all in c/c++ style .

The problem is asambly/ instructionset 16c63 ,
I just don't know how to declare variables, make a while loop , for loop
, if thenb else , case and  functions.

I downloaded the book The Art of Assembly Language Programming but this
is a 8086 instruction set book.

I red in the manual of the 16c63 that c is suported, maybe this is the
best thing for me ?
But if i do am i stil able to do the thing i want the program to do ?

Can you please help me , or direct me to info on the net ?

ps

sorry for the bad english

2000\05\07@064703 by Ravi Pailoor

flavicon
face
Sorry, his email address is  "ron" <TakeThisOuTrolexEraseMEspamspam_OUTwestbrabant.net>

Pailoor

More... (looser matching)
- Last day of these posts
- In 2000 , 2001 only
- Today
- New search...