Hello,I am new to this forum and so I hope that I can explain what I am seeing (or not seeing to be accurate) properly. Also, my keyboard underwent cleaning by my Niece recently and has ceased to function properly, so expect spacing errors among others.
Pictures not available (no camera/webcam or cell 'phone WITH a camera).
I have recently purchased the above listed A4988 stepper motor driver and after spending several days wiring a test board and checking the wiring, I seated the board and proceeded to the calibration method listed in the PololuPres_V3.pdf.
The power supply is an ATX 300 watt supply using only the 5v output and ground (except for a temp connection to the 12vdc line for this test). This is/was powering two other circuits successfully.
The problem that I have encountered is that during the calibration process I can not measure any current on the Bipolar motor output pins as per the pdf. and there is no motor movement at all. The A4988 chip becomes slightly warm to the touch via the heatsink indicating that there is at least something going on. Here is a bit of a checklistâŚ
Antistatic in place. Verified
Connected enable, ms1,ms2 and ms3 to gnd. Verified
Connected Sleep and reset together. Verified
Voltage measured at Sleep/Reset = 2.06 vdc. Verified
Connected Step and Direction to gnd. Verified
Connected 12vdc (ATX Power) to VMOT (as a temp hookup). Verified
Connected motor wires to terminal (1A 1B / 2A 2B) with multimeter (current mode) inline coil connections 2 A and 2B. Verified
Connected 5 vdc (ATX power) to VDD. Verified
Checked all gnd connection. Verified
Checked 12 vdc and 5 vdc on proper pins. Verified
Check for voltage short in circuit (prior to installing A4988 board) none located. Verified
Check header pins to solder points on A4988 circuit board. Verified
Connected 24 vdc supply to VMOT (required by motor) to see if low voltage was the problem, no go. Verified
The motor is a PM35S-048-HHC6 24 volt 600ma 5.5 ohm. Also tested with 4018x-07-04 5 v 1 amp bipolar motor.
I was also able to measure a small voltage on the via between the chip and the pot which ran from 1.3 to 0 depending on the pots position.
As stated, I get no current reading (0.0-0.1) at the output specified by the pdf, nor any of the other outputs. The motor does not twitch, vibrate, âsingâ, moan groan or recite the Gettysburg Address (I could make a million with a motor like that!). I have also swapped motor leads (With the powers disconnected) as per instructions found on the web for identifying the proper motor connectors.
Respectfully request HELP!
Eldraad