95lstegman
01-27-2008, 09:33 AM
background:
okay, so we have an eddy brake retarder that we acquired for cheap. it surely can handle the power of a small FSAE-type engine. i have been tasked with improving the load control abilities of this unit. the adjustable power supply we have does not supply enough power; we have an additional supply that simply supplies a set amount of current and is either on or off. this box will be easy to control with labview, and i don't have a problem with that part. labview and a large/powerful NI DAQ board will be used exclusively to gather data and control devices as needed.
more specific info:
the team here are very touchy about the adjustable power supply, and don't want me to dig into it. they would rather i use a stepper motor to control the little knob that is on the face of the box. i'm a ME major, so this isn't my specialty, but i've been digging into steppers lately, and it seems to me it's a heck of a hassle when i could simply open up the adjustable supply box itself, remove the knob, and directly drive the control circuit. with a stepper, either it's a big pain in the neck to create controls myself, or it's rather expensive to get very fine control with a whole stepper setup. i'm pretty sure i won't have the time in the near future to develop a good working knowledge of how to directly control a stepper, and this is a priority issue.
the knob itself is about 1" diameter, ~3in-lb turning torque, and only 330deg. rotation for full range of current adjustment, so it needs fine adjustment. also needs to respond quickly, and change direction quickly.
the prompt:
so, does anybody have a relatively cheap solution to the stepper motor + controller + power supply situation? or perhaps there is a much simpler way to control a little hand knob?
okay, so we have an eddy brake retarder that we acquired for cheap. it surely can handle the power of a small FSAE-type engine. i have been tasked with improving the load control abilities of this unit. the adjustable power supply we have does not supply enough power; we have an additional supply that simply supplies a set amount of current and is either on or off. this box will be easy to control with labview, and i don't have a problem with that part. labview and a large/powerful NI DAQ board will be used exclusively to gather data and control devices as needed.
more specific info:
the team here are very touchy about the adjustable power supply, and don't want me to dig into it. they would rather i use a stepper motor to control the little knob that is on the face of the box. i'm a ME major, so this isn't my specialty, but i've been digging into steppers lately, and it seems to me it's a heck of a hassle when i could simply open up the adjustable supply box itself, remove the knob, and directly drive the control circuit. with a stepper, either it's a big pain in the neck to create controls myself, or it's rather expensive to get very fine control with a whole stepper setup. i'm pretty sure i won't have the time in the near future to develop a good working knowledge of how to directly control a stepper, and this is a priority issue.
the knob itself is about 1" diameter, ~3in-lb turning torque, and only 330deg. rotation for full range of current adjustment, so it needs fine adjustment. also needs to respond quickly, and change direction quickly.
the prompt:
so, does anybody have a relatively cheap solution to the stepper motor + controller + power supply situation? or perhaps there is a much simpler way to control a little hand knob?