Failsafe mechanisms
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- Simon Windisch
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Failsafe mechanisms
Hi there,
I'm using a new SOZBOTS - MX Speed Controller http://www.sozbots.com/stores/popups/SOZDSCR2.htm and am horrified to learn that it does not fail safe if the transmitter turns off.
Has anyone else had experience of this?
Simon
I'm using a new SOZBOTS - MX Speed Controller http://www.sozbots.com/stores/popups/SOZDSCR2.htm and am horrified to learn that it does not fail safe if the transmitter turns off.
Has anyone else had experience of this?
Simon
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- Simon Windisch
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- Simon Windisch
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- BeligerAnt
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Simon, I assume you've read the manual?
Does the board behave like the manual says it should? It infers (but doesn't explicitly state) that there is some sort of failsafe.
Is your receiver well-behaved? The manual mentions "glitchy" receivers. How does your rx behave with standard servos connected? Is it picking up interference from your PC/mobile phone/etc?
Are all your motors suppressed with ceramic capacitors right across the motor terminals?
Standard servos only have a kind of simple "accidental" failsafe, in that they will generally try to hold position (i.e. stop) in the absence of any data. Noise picked up by a receiver is often interpreted as data and servos will misbehave.
Speed controllers on the other hand usually have a much more sophisticated failsafe mechanism. At power-on they usually wait for a valid "neutral" pulse (or several) before enabling the motor drive circuit. The chances of getting a string of 1.5ms pulses out of the receiver as a result of random interference are slim so the failsafe is quite effective.
To help the support guys diagnose/fix your problem, give them as much information as possible. What is the exact setup? What is the exact sequence of events? What does the LED do? How do the motors run? (Full speed, slowly, steady, erratically, etc) Is the behaviour repeatable? Have you tried different configurations? (Different receiver, crystal, motors etc)
Does the board behave like the manual says it should? It infers (but doesn't explicitly state) that there is some sort of failsafe.
Is your receiver well-behaved? The manual mentions "glitchy" receivers. How does your rx behave with standard servos connected? Is it picking up interference from your PC/mobile phone/etc?
Are all your motors suppressed with ceramic capacitors right across the motor terminals?
Standard servos only have a kind of simple "accidental" failsafe, in that they will generally try to hold position (i.e. stop) in the absence of any data. Noise picked up by a receiver is often interpreted as data and servos will misbehave.
Speed controllers on the other hand usually have a much more sophisticated failsafe mechanism. At power-on they usually wait for a valid "neutral" pulse (or several) before enabling the motor drive circuit. The chances of getting a string of 1.5ms pulses out of the receiver as a result of random interference are slim so the failsafe is quite effective.
To help the support guys diagnose/fix your problem, give them as much information as possible. What is the exact setup? What is the exact sequence of events? What does the LED do? How do the motors run? (Full speed, slowly, steady, erratically, etc) Is the behaviour repeatable? Have you tried different configurations? (Different receiver, crystal, motors etc)
Gary, Team BeligerAnt
- Simon Windisch
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