HB25 Manual Override?

Jock

Hi I am running a 12V actuator from my basic stamp 2 using a HB25 motor controller.
I wish to put a manual override on the actuator by using a double pole double throw momentory switch connected to the outputs M1 & M2 of the HB25, the polarity of the switch is reversible to drive the actuator in 2 directions, will applying this voltage to the outputs of the HB25 cause it or the stamp any issues???
Thanks

Chris Savage

Richard,
·
·· It sounds like you’re suggesting applying reverse voltage to the HB-25…That is, reverse with respect to its output.· If that is the case it would be like a short on the output…Please clarify what you mean if my assumption was incorrect.

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Chris Savage
Parallax Tech Support

Jock

Hi Chris,

Thanks for the reply.

I am suggesting that I apply 12dc directly to the HB25 outputs M1 & M2 (by way of a manual switch as an override to the stamp and HB25 method of control of the actuator and assuming the HB25 wasn't driving the actuator at the time), would that damage the HB25 or stamp?

Thanks and Regards
Richard

PAR

Richard Little said...
Hi I am running a 12V actuator from my basic stamp 2 using a HB25 motor controller.
I wish to put a manual override on the actuator by using a double pole double throw momentory switch connected to the outputs M1 & M2 of the HB25, the polarity of the switch is reversible to drive the actuator in 2 directions, will applying this voltage to the outputs of the HB25 cause it or the stamp any issues???
Thanks

In essence, are you saying that you want to disconnect the HB25 from the motor (actuator) and connect the motor directly to a 12V power supply (momentarily, with polarity selected by the switch throw depending on your need)?

If so, then it seems that a break-before-make switch would be needed --breaking the connection of the HB25 to the motor before making the connection from the 12V source directly to the motor (and vice-versa when reconnecting the HB25).

You do not want to "apply this [noparse][[/noparse]12V] voltage to the outputs of the HB25", but rather to the inputs of the motor (only).

You will also want to assure that your switch is positioned correctly (forward or backward direction of motor) before you release the switch (and reconnect the HB25) so that the HB25 is reconnected to the motor with the intended polarity.

One further consideration you need to ask soemone else·about: Will an instantaneous disconnect of the hb25 from the motor (load) while that motor is running cause any problem for the HB25 and/or Stamp?· (I don't know)

PAR

Jock

Hi PAR

Thanks for that, you have 'hit the nail on the head' exactly with what I am trying to do.

I hadn't thought of a switch disconnecting the HB25 when the 12V supply was connected (oops).

It would certainly be easier to achieve if I didn't have to disconnect the HB25 as I could apply the 12v in either polarity directly with a DPDT mom sw. Not sure how I would achieve the disconnect and either polarity from one switch?

Cheers

Richard

Chris Savage

Richard,
·
·· Okay, yeah PAR has you covered. ·What I was worried about was what you mentioned later…Disconnecting the HB-25 from the new power source. ·That should be safe.

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Chris Savage
Parallax Tech Support

Desy2820

I'm not fully understanding what your project is, but since you're already using a Stamp, could use the stamp to monitor your override switch, then reverse or stop the HB-25?

My other thought would be limit switches, so if the actutor hit the limit switch, the stamp would see the signal and reverse the actuator.

Just throwing some ideas out there...I hope I helped.

Ro'King M

hi

if I understand your problem. you are to turn the HB25 ON by using the pulsout from the BSII, and then leaving the BSII do it stuff.
if you are using something like this CODE, in your i will have to isolate the BSII like using opto coupler/relay.

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[noparse][[/noparse] I/O Definitions ]

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HB25 PIN 2 ' I/O Pin For HB-25

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[noparse][[/noparse] Variables ]

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index VAR Word ' Counter For Ramping

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[noparse][[/noparse] Initialization ]

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DO : LOOP UNTIL HB25 = 1 ' Wait For HB-25 Power Up
LOW HB25 ' Make I/O Pin Output/Low
PAUSE 5 ' Wait For HB-25 To Initialize
PULSOUT HB25, 750 ' Stop Motor 1
PAUSE 2 ' 1 mS Delay
PULSOUT HB25, 750

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[noparse][[/noparse] Program Code ]

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PAUSE 20 ' Wait 20 mS Before Ramping
FOR index = 250 TO 250 ' Ramp Up To Full Speed
PULSOUT HB25, 750 + index ' Motor 1 Forward
PAUSE 1 ' 1 mS Delay For Motor 2 Pulse
PULSOUT HB25, 750 - index ' Motor 2 Reverse
PAUSE 20 ' 20 mS Smoothing Delay
NEXT
PAUSE 3000 ' Wait 3 Seconds
FOR index = 250 TO 250 ' Ramp Back Down
PULSOUT HB25, 750 + index ' Motor 1 Forward Slowing
PAUSE 1 ' 1 mS Delay For Motor 2
PULSOUT HB25, 750 - index ' Motor 2 Reverse Slowing
PAUSE 20 ' 20 mS Smoothing Delay
NEXT
STOP ' Use STOP To Prevent State Change

in that case since u dont want to shut off the HB25, I'll probably use some sort of a mechanical relay or opto coupler. But in this case i would use an opto coupler because it will be safer for any potentialy high voltage spark if you use a mechanical relay. you may want to build a squqre wave generator and connecting it to the signal in put of the HB25 setting the square wave generator to 2.5mS so you can change the direction of the motor any given time IF U DONT WANT DAMAGE THE BSII.