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Basic Stamp & DS1302 Time Chip & In-Put Switches & remember the last State with power — Parallax Forums

Basic Stamp & DS1302 Time Chip & In-Put Switches & remember the last State with power

sam_sam_samsam_sam_sam Posts: 2,286
edited 2012-02-20 13:34 in General Discussion
Here are the part that I am going to use

Basic Stamp
DS1302 Time Chip
In-Put Switches

I want to remember the last State the switch is in with power lost and when power is restored the state of that switch is returned

Here is why where I work there was an in another facility with a over head crane

Here is what happen the person was going up with a load and the crane hoisted hits the upper limit switch which is what should happen
but the hoist motor is suppose to STOP how ever the contact-or contacts welded together and motor kept running and the cable broke and the hook fell to the ground

NO ONE was hurt in this accident

Our facility was told to set up our crane to where if the hoist goes past the first limit and hits the second limit switch that power it is shut OFF to the hoist
and not allow to restart until the crane has been work on to see why it when to the second limit switch

The second limit switch is being add to all of our crane

From what I understand there is NO off the shelf add on to do this So my thought is to have it where when this happen
when hook block hit the second limit switch the power is shut OFF to UP DOWN contact-or until maintenance person climb up on to the crane to trouble shoot what happen

Comments

  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2012-02-15 17:35
    I know how to write and read to DS1302 time chip

    How ever I not sure how to save the last state of an input to the DS1302 time chip and if the power is lost how to read the state of the input from memory from the DS1302 time chip
    To keep the output of the Basic Stamp is LOCK OUT until a INPUT switch is pushed to clear the input FLAG




    ' {$STAMP BS2}
' {$PBASIC 2.5}
'DS1302_Ram_Save_Demo
DataIO          PIN    1               ' DS1302.6
Clock           PIN    0               ' DS1302.7
CS1302          PIN    2               ' DS1302.5
LED             PIN    4               ' Led to see if INSwitch is open
chg_S           PIN    8               ' Switch to REset ALL Data
Chg_P           PIN    9               ' Switch to REset Product Data used for a Job
InSwitch        PIN    10              ' INPUT From Dead Man Switch
LCD             PIN    15
' -----[ LCD Constants ]-------------------------------------------------------
DispLightOn     CON     $11
DispLightOFF    CON     $12
LineOne0        CON     $80
LineOne1        CON     $81
LineTwo0        CON     $94
LineTwo1        CON     $95
LineTwo4        CON     $98
ClearScreen     CON     $0C
Baud            CON     32              ' baudmode constant for LCD Display

P               VAR     Word
S               VAR     Word
reg             VAR     Byte
S_Reg           VAR     Byte
cntr_S          VAR     Byte
cntr_P          VAR     Byte

'GOSUB resetData
SEROUT LCD, Baud, [Clearscreen]
PAUSE 200
Clear:
          cntr_S = cntr_S + 1 *  Chg_S               ' This line is to check if state of pin 8
      IF (cntr_S = 6 ) THEN GOSUB resetData          ' The ReSet button has to be press to clear Data
          cntr_P = cntr_P + 1 *  Chg_P               ' This line is to check if state of pin 9
      IF (cntr_P = 6 ) THEN GOSUB P_resetData        ' The ReSet button has to be press to clear Data
DO WHILE INSwitch = 1
GOSUB RdRam
p = p + 1
s = s + 1
GOSUB WrRam
SEROUT LCD, Baud, [LineOne0,   " Prod ", DEC5  P, CR]
  SEROUT LCD, Baud, [LineTwo0, " Silo ", DEC5  S]
LOOP
GOTO Clear
WrRam:
  reg = $FE
  HIGH CS1302
  SHIFTOUT DataIO, Clock,LSBFIRST, [reg]
  SHIFTOUT DataIO, Clock, LSBFIRST, [P.HIGHBYTE,P.LOWBYTE,S.HIGHBYTE,S.LOWBYTE]
  LOW CS1302
RETURN
RdRam:
  reg = $FF
  HIGH CS1302
  SHIFTOUT DataIO, Clock, LSBFIRST, [reg]
  SHIFTIN DataIO, Clock, LSBPRE, [P.HIGHBYTE,P.LOWBYTE,S.HIGHBYTE,S.LOWBYTE]
  LOW CS1302
  DEBUG HOME, "Product = ",DEC2 P," S ",DEC5 S, CR
  SEROUT LCD, Baud, [LineOne0," S ",  DEC  S, " P ",  DEC P , CR]
RETURN
resetData:
 GOSUB WrRam
P.HIGHBYTE  = 00000
P.LOWBYTE   = 00000
S.HIGHBYTE  = 00000
S.LOWBYTE   = 00000
RETURN
P_resetData:
 GOSUB WrRam
P.HIGHBYTE  = 00000
P.LOWBYTE   = 00000
  RETURN
  • kwinnkwinn Posts: 8,697
    edited 2012-02-15 18:00
    sam_sam_sam wrote: »
    Here are the part that I am going to use

    Basic Stamp
    DS1302 Time Chip
    In-Put Switches

    I want to remember the last State the switch is in with power lost and when power is restored the state of that switch is returned

    Here is why where I work there was an in in another facility with a over head crane

    Here is what happen the person was going up with a load and the crane hoisted hits the upper limit switch which is what should happen
    but the hoist motor is suppose to STOP how ever the contact-or contacts welded together and motor kept running and the cable broke and the hook fell to the ground

    NO ONE was hurt in this accident

    Our facility was told to set up our crane to where if the hoist goes past the first limit and hits the second limit switch that power it is shut OFF to the hoist
    and not allow to restart until the crane has been work on to see why it when to the second limit switch

    The second limit switch is being add to all of our crane

    From what I understand there is NO off the shelf add on to do this So my thought is to have it where when this happen
    when hook block hit the second limit switch the power is shut OFF to UP DOWN contact-or until maintenance person climb up on to the crane to trouble shoot what happen

    Two limit switches are fairly common on mechanical systems. The first limit switch goes to the control electronics which commands it to stop. The second switch is usually a normally closed contact in series with the coil of the main power relay. When this switch opens it removes all power from the equipment. In many cases there is also a latching relay or mechanical latch that must be manually reset before power can be restored to the system.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2012-02-15 18:32
    kwinn

    Thank you for your reply

    I would like to do this with a Basic Stamp

    Here is why we have one crane that at least 25 to 30 years old it dose not have a lower limit switch

    What I want to is IF some one hold the down button on the remote for longer than what it take for the hosit hook block to go from the top limit switch to the ground then it would stop the motor until the up switch is push for so many seconds

    I know that this not fool proof but it is better than nothing
  • kwinnkwinn Posts: 8,697
    edited 2012-02-15 19:37
    For this you could use a latching relay as the memory element and to activate the relay/circuit that controls the crane motor. A latching relay remains in whatever state it is in when the power is removed. It needs power to turn it on and power to turn it off.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2012-02-15 23:06
    kwinn

    Thank you for your reply

    Could you post a web link to the type of latching relay that you are talking about I have never use one Thanks for all of your help
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-02-16 02:10
    Remembering the position of a switch when ALL power is lost and allowing it to be reinstated when power returns.........

    A latching relay is likely the best solution for that. After all, what happens to the BS when power is lost, it wipes its memory.
  • MoskogMoskog Posts: 554
    edited 2012-02-16 08:49
    Loopy Byteloose wrote: »
    After all, what happens to the BS when power is lost, it wipes its memory.

    Yes, but it's last action was to write it's state to the time-chip's memory.
  • tonyp12tonyp12 Posts: 1,951
    edited 2012-02-16 09:46
    As long the RTC ic have battery backup you can program the state in it's 31byte ram.

    But they make 2 and 4pin remember-state ICs
    3V 1.27mm SOIC http://www.mouser.com/ProductDetail/Ramtron/FM1106-GA/?qs=sGAEpiMZZMtsPi73Z94q0CkDToGtzUA7WawxTTmnW5I%3d

    5V small 0.65mm SOT http://www.mouser.com/ProductDetail/Ramtron/FM1105/?qs=sGAEpiMZZMtsPi73Z94q0KcM%252bBSzTxqK2Vl%252bDrW9N6I%3d
    better have good sight to put it on a smt-board, other sites may have soic version of this 5v
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-02-16 22:55
    Yes indeed, you can program state data into RTC memory buffers - BUT when the BS is reset in a power down, you still will have a momentary reset of all I/O pins and that may NOT be acceptable.

    There are workarounds for this problem, but none are quite as good as a latching relay.
  • kwinnkwinn Posts: 8,697
    edited 2012-02-18 15:59
    Lots of latching relays available. Here are a couple that Digi-Key carries:

    http://parts.digikey.com/1/parts/374592-plc-relay-spdt-24vdc-2966171.html
    http://parts.digikey.com/1/parts/374593-plc-relay-spdt-24vac-dc-2966184.html

    In typical safety circuits these are in series with the coil of the relay that provides power to the motors or equipment so the exact relay you use will depend on the rating of that coil. Normally such equipment would have a manual reset button but a microcontroller could also do that. Since the micro does not need to remember the state of the switch no RTC chip is needed. A timing loop running on the micro when the up button is pressed is all that is required. In fact a 555 timer could probably do that.

    OOPS - Scratch the 555 timer. Forgot about timing how long the down button was pressed.

    BTW the down time count should probably be cumulative so it tracks the total amount of down travel even if the button is released from time to time.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2012-02-18 17:47
    This is a dual coil latching relay

    Here is what I am looking for[IMG]http://media.digikey.com/photos/Panasonic Elect Works Photos/SP2-L2- SERIES_sml.jpg[/IMG]http://search.digikey.com/us/en/products/SP2-L2-DC24V/255-2839-ND/649193

    After it was all said and done my boss decide not to go with a microcontroller and do it with a relay instead
    I want to thank all of you that replied to this post

    I will to build a 24 volt power supply to to use this relay

    When I am on the other laptop computer I will post the code that wrote to do this there is a 100 th of a second where it powers up that pin but that may have work any way
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2012-02-18 18:10
    kwinn wrote: »
    . Since the micro does not need to remember the state of the switch no RTC chip is need.

    In a way it dose because if you base your code on what state of the input is before the power is lost and when it is restored you might be able to restart the hoist motor again

    The way I wrote the code was when you turn on the power and the input was low the contractor would be ON if the input went high then it would turn OFF and stay OFF until a second input went high to reset the first input but you would a second switch to disabled the first input

    But i might be making this harder than it need to be

    I do want to thank you for all of your help in this matter
  • kwinnkwinn Posts: 8,697
    edited 2012-02-18 20:28
    If the power supply is only powering the relay it can be pretty simple. The relay coils only draw 12.5mA so a small 24V transformer a bridge rectifier, and capacitor are really all you need.

    As for making this harder than it has to be, yes you probably were. A safety circuit needs to be reliable so the simpler you make it the better. You do not want hoists starting up by themselves when the power comes back on.

    BTW how are you going to do the timing of the down movement without a micro?
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2012-02-20 13:34
    [QUOTE=kwinn;1075667 BTW how are you going to do the timing of the down movement without a micro?[/QUOTE]

    I was going add this on one of the hoist if I was using a micro controller
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