[RCSE] servo-receiver behavior question
Ok, so, when an onboard battery pack winds down to nearly exhausted, and the servos start to get erratic, meaning they start moving to do the requested motion, but only get part way there, then quit, then jump the rest of the way, perhaps in two or three of these steps for a full deflection, what exactly is going on? Is this the servo simply demanding more power than the battery can provide? Why isn't the servo simply slowing way way down, as opposed to jerking in steps to its destination? Does the receiver have any role in creating this erratic motion? Is the receiver somehow cutting in and out or is this familiar behavior just a symptom of how the power demands cycle between the servos and the battery? Thanks for insight from anyone with more mastery of electronic interactions than I have (which is an awful lot like just saying anyone) Lift, Scobie in Seattle. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] servo-receiver behavior question
Scobie - Here is my guess...and this is just a guess. The servos require a certain amount of voltage to work. Moving the servo puts a load on the battery and causes the voltage to drop a little bit. Once the load is taken off of the battery, the voltage will jump up a little bit. So, if you're at the limits of what it takes to move the servo: The servo starts to move then pulls down the battery too low for the servo to move. Once the servo is no longer putting a load on the battery the pack starts to go up in voltage. The threshold for the servo voltage is met and the servo starts to move again. This could also be a function of the voltage the RX needs to work as well. If the RX is powering on and off because of the servo load you'll experience the same problem. Most receivers require less voltage to work than servos do...at least in my experience. It's always a good idea to stop flying when you have these issues :-) Jared -Original Message- From: Scobie Puchtler [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 26, 2005 6:07 PM To: RCSE Subject: [RCSE] servo-receiver behavior question Ok, so, when an onboard battery pack winds down to nearly exhausted, and the servos start to get erratic, meaning they start moving to do the requested motion, but only get part way there, then quit, then jump the rest of the way, perhaps in two or three of these steps for a full deflection, what exactly is going on? Is this the servo simply demanding more power than the battery can provide? Why isn't the servo simply slowing way way down, as opposed to jerking in steps to its destination? Does the receiver have any role in creating this erratic motion? Is the receiver somehow cutting in and out or is this familiar behavior just a symptom of how the power demands cycle between the servos and the battery? Thanks for insight from anyone with more mastery of electronic interactions than I have (which is an awful lot like just saying anyone) Lift, Scobie in Seattle. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] servo-receiver behavior question
Anyone? Cool, I'm there for ya. Both the servos and the RX are, essentially, on the same bus. Thus, the voltage to one is the same as the voltage to another. Your description sounds like the servo simply requesting more energy than the battery can provide and the voltage drops dramatically. What happens then I can't say. But I think it differs with different components. It will depend on each component and situation. How much will the voltage be pulled down? Will the RX quit first? Will the servos quit first? Will both quit? Is there enough juice in the battery to recover nominal voltage? But, it's academic really. You shouldn't be playing close to the edge. Personally, several of my planes that I have experienced this with gave no warning. They flew normally until simply going dead in the air. One time it corresponded to a large stick input which the battery couldn't handle nor recover from. Which is pretty logical. One minute normal, the next I slammed into an aileron roll and 'Poof' the plane was dead and still rolling all the way to the ground. Thud. Bill Swingle RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
