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Forum Newbie
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Last Login: Saturday, April 25, 2009 8:12 AM
Posts: 7,
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| I recently added the Serializer to my arsenal of devices. I was excited about the built-in PID. Come to find out I can't use it with my Sabertooth 2x25 the way I'd like from the Serializer PID. In my case, as well as other posts here, we need 0volts for full reverse, 2.5v for stop and 5v for full forward as a pwm input(using analog mode). Is there any plans in the near future to implement an option to change this? Is there a known circuit I can make to convert the pwm output to the range used by my sabertooth and keep the PID functions? I have huge 24v wheelchair motors on my bot and the little H-Bridges on the Serializer aren't gonna cut it. The Sabertooth was well worth the $$ to me as it is a workhorse and doesn't flinch to heavy load, like me sitting on my bot and riding it around. LOL Please help me  meistro
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Forum Newbie
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Last Login: Saturday, April 25, 2009 8:12 AM
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 anyone?
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Supreme Being
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Last Login: Friday, April 22, 2011 6:18 PM
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I suggest you acquire a external H-Bridge for your voltage / current needs that supports
the four output signals of the serializer h-bridge header. You may still have to add
a little circuitry for control between the serializer and external h-bridge.
Serializer signals:
Direction = 1 or 0
pwm A = variable pulse width
pwm B = " " "
Enable = 1 or 0
all signals 0 - 5vDC
Don Lewis
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Forum Newbie
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Last Login: Tuesday, April 27, 2010 9:18 PM
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| I have the sabertooth 2x25 and I am trying to use the external H-brige on the serilaizer to provide a pwm signal to the sabertooth. I am trying to use the sabertooth in packetized serial mode were I only need to connec the S1 and GND terminal to the serializer. Can anyone tell me exactly which pins on the external H-bridge of the serializer to connect to? In the manual, it suggests the following: "If you wish to surpass the internal H-Bridges, and drive external H-Bridges w/ a higher rating, you can cut the traces on the bottom of the board, and connect the h-bridges to the pins w/ jumper wires as shown (in orange) below: If you cut the traces and then decide to go back to using the onboard H-bridges, simply make sure all jumpers are installed across the five H-Bridge pins (as shown above). " Since I want to use the external H-Bridge how do I cut the traces at the bottom of the serializer. I am a newbie and dont want to possibly damage the serializer.
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Forum Guru
Group: Moderators
Last Login: Wednesday, March 16, 2011 1:17 PM
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You do not have to cut the traces. You can do that if you want to disable the H-bridges on the the serializer, but leaving them connected does not hurt anything. In fact if you leave them connected you can use the leds on board as status indicators.
Ringo
Ringo Davis
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Forum Newbie
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Last Login: Tuesday, April 27, 2010 9:18 PM
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Ok great, can you tell me exactly which pins to use given my setup mentioned above. When i tried connecting the s1 to the L_PWM terminal and the Ground wire to the R_PWN terminal, my motor just started running by itself.
I assume I had the wrong connection so please tell me which pins to use
Thanks
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Forum Member
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Last Login: Saturday, August 14, 2010 12:06 PM
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The Sabertooth 2x25 in "Packetized Serial" mode requires a serial port, with a "packet" of data sent to it, such as address, direction, speed, etc. (can't remember the exact protocol--reference the Sabertooth Packetized Serial manual).
The PWM outputs of the Serializer are not the same thing as the packetized serial protocol that the Sabertooth module requires.
It is possible to create an analog voltage from a PWM signal, but the complexity of this interface is high (if you involve level shifters and signal conditioning) and the results will be inferior to using a serial port and controlling the Sabertooth with the packetized serial protocol.
I understand that you have a vested interest in using the Sabertooth module; but FWIU the Sabertooth modules are focused on interfacing with R/C type gear/remotes.
With that said, you *may* be successful in using your Sabertooth 2x25 motor controller with the Serializer by setting your Sabertooth DIP switches to use R/C mode. You would then connect a couple of the Serializer's SERVO channels to the Sabertooth, which will allow you to control the speed and direction of the motors by sending a "servo x:y" command from the Serializer (refer to the Serializer documentation).
Finally, be sure to set your DIP switches according to the proper mode 
Good luck,
--Scott
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