Datasheet

STEP 4: CONNECTING CONTROL INPUTS
The STEP and DIRECTION signal drivers must be 3.3V or 5V TTL signals and have edge transition times of 100 ns or faster. The
COMMON input can be connected to signal ground or a +5VDC supply. The G320X default motor direction is CW when the
DIRECTION pin is left unconnected.
TERMINAL 10 Direction
Connect the DIRECTION line to this terminal.
TERMINAL 11 Step
Connect the STEP line to this terminal.
TERMINAL 12 Common
Connect this terminal to the signal ground or +5VDC.
STEP 5: TESTING THE STEP AND DIRECTION INPUTS
Set the STEP pulse generator to 40 pulses per second. If you are using a CNC program, use the “JOG” command. Turn on the
power supply; the FAULT indicator (red) will turn off after 1 second and the IN-POSITION indicator (green) will turn on. Start
sending step pulses (JOG). The IN-POSITION indicator (green) will turn off almost immediately, the WARN indicator (yellow) will
turn on 3 seconds later and the FAULT indicator (red) will turn on 3 seconds after that. Once the FAULT indicator (red) turns on,
stop sending step pulses. Send step pulses in the opposite DIRECTION and the above process should repeat.
STEP 6: CONNECTING THE MOTOR
Turn the power supply and the step pulse source off. Verify that the “P”, “I”, “D”, and LIMIT trimpots are in the 11 o’clock
position.
TERMINAL 3 Armature (-)
Connect the BLACK motor lead to this terminal.
TERMINAL 4 Armature (+)
Connect the RED motor lead to this terminal.
STEP 7: TUNING THE SERVO
Turn on the power supply. The FAULT indicator should turn off and the IN-POSITION indicator should turn on after 1 second. If
everything is correct you may hear faint sounds coming from the motor. This is normal. The motor is “dithering”, or bouncing
between adjacent encoder counts. The integral term in a PID loop has infinite DC gain over time and will amplify even the
smallest position error. Because encoder feedback can only occur on count edges, the loop is “blind” until it encounters an
encoder count edge. It then reverses the motor direction until another edge is found, then the process repeats.
If the motor jumps slightly and the FAULT indicator immediately turns back on, then either the motor is wired backwards or the
trimpots are misadjusted. Check the trimpot settings. If they are correct then switch exchange CH A and CH B. If it still doesn’t
work and you followed all the previous steps, call Geckodrive at the number at the end of this document.
Now try turning the motor gently by hand. The motor should resist being turned and the IN-POSITION indicator may flicker.
CAUTION: Do not move the motor manually for more than several seconds at a time; motor overheating will occur if you do.
Now turn on the power supply and step pulse source and ramp the speed up to see if the motor turns.
The default PID trimpot settings should work in most applications. The PID settings do not in any way affect the positioning
accuracy of the G320X and only affects the settling time of the servo. To use an oscilloscope you must remove the cover and
place the probe on TP1. There are four solder pads approximately 2mm in diameter near the DIP switch; the two closest to the
center of the board are TP1 and the two closest to the edge of the board are GND.