Give it a G97 in MDI first, then press START to be sure that you are not in constant surface speed.
Check to be sure parameter 00 bit # 5 (the 6th bit from the right) is a "1". That's the option parameter for constant surface speed control.
You should also have some switch inputs that tell the control which gear the headstock is in. If you only have one gear range, that's OK too, but most lathes have more than one gear range between the spindle motor and the chuck. The MAXIMUM spindle speed for each gear range is set in parameters 55 and 56 are used to set the maximum spindle speed in gear range 1 (when the motor is going at full RPM) . Parameters 57 and 58 are used to set the maximum spindle speed in gear 2. Parameters 59 and 60 are for gear range 3, and parameters 61 and 62 are used to set gear range 4.
You might have these parameters zeroed-out, or you might have a bad limit switch so the control doesn't know what gear range it's in. |