November 28, 2006
Hello all,
I have a few questions from the Data Sheets that Xylotex includes with their 3 axis board.
http://www.xylotex.com/XS3525V202.pdf
1.
This quote from the data sheet:
“The on-board drive circuitry limits the source/sink current to the motor without the need for external power resistors.”
I was trying to find out what source/sink current is and I came upon this analogy on the web:
"Current sources and sinks are local electrical currents that flow from a location where they can’t be detected into a location where they can be detected (current source) or vice versa (current sink). By analogy to the flow of water, a current source would be like a mountain spring. A current of water flows from a hidden location underground to the surface where it can be easily seen. A sink on the other hand would be like water flowing down a drain. It flows from where you can see it to where you can’t. Electrical current can have the same basic properties. Current flowing from the “live” wires of an electrical outlet would be a source, while current flowing back along the common would be a sink (although with AC circuits this distinction gets a little murkey)”
Does this quote explain the boards use of source/sink current? If so could someone draw a parallel for me between this quote and how it would apply to the above quote taken from the data sheet for the 3 axis board?
Also, in my research about power resistors, I concluded that a power resistor is just a resistor that can maintain a voltage given its resistance and the current, but at the same time, can dissapate more heat than say a smaller resistor with the same resistance. So these resistors are usually larger than say a ¼ watt or ½ watt resistor type. Does a source / sink current create heat? And is the circuitry designed to avoid this heat? Is this propriatary to the design or could some briefly explain how this is accomplished?
2.
I noticed on the three axis board there is a connector at the bottom with the following markings: GND, DIRA, STEPA, Vcc. I’m assuming that this would be for a connection to a fourth axis such as Xylotex’s 1 axis board which has a connector with markings
G, D, S, +5.
Thanks again,
Dan