User project:VMC100 CNC mill update

From Granite Devices Knowledge Wiki
Jump to: navigation, search

I have replaced a 80s EMCO TM-02 controller with MACH3 PC based control system including new electronics for a VMC-100 CNC mill.

There is a servo controller, stepper controllers, programmable logic controller (PLC) and some power supplies and minor things. Interface to PC is via parallel port, using a VSDEPI break-out-board (BOB) from Granite devices. The original EMCO mill connectors are cut away and cables are connected to new electronics located in a metal cabinet bolted to the left side of the mill. There is also a large transformer for changing 230Vac voltage to 110Vac for the Vexta stepper controllers - this voltage is also handy for the servo powersupply, and offers isolation from mains.

Servo controller is Granite Devices VSD-E 160. It has a simple 150Vdc high-voltage powersupply based on a rectifier bridge and storage capasitor. PLC controls a relay that short-circuits a current inrush limiting resistor at the DC powersupply circuit. There is a bleeder resistor to bleed the charge from capasitor when power is switched off - the energy stored in the capasitor is easily enough to kill a person. Spindle control is with step-direction -control from PC. The tool changer rotation is based on spindle servo, so spindle had to be a true servo spindle instead of a more simple RPM control. In the servo controller there is scaling of the input pulses so that the full speed of spindle can be reached with the limited pulse rate of PC parallel port. This limits angular accuracy of spindle, but is a necessary compromise.

Stepper controllers are Vexta (Oriental motor) UDK5128. They can drive the 5-phase penta-connected original Berger-Lahr steppers of the mill. The control is with step-direction -control. I have also added X and Y axis limit switches, as EMCO design relied on software limits only. The overheat output signal goes to PLC from stepper controllers, and PLC controls enable input of stepper controllers. The stepper input/output signals are optically isolated so interfacing is simple.

Here is a conceptual schematic:

VMC100 KU v101 page1.gif

In no event the Product Information or parts hereof shall be regarded as guarantee of conditions or characteristics. The Product Information or any part thereof may also not be regarded as a warranty of any kind. No liability of any kind shall be assumed by Author with respect to Product Information or any use made by you thereof, nor shall Author indemnify you against or be liable for any third party claims with respect to such information or any use thereof.

As content of this Wiki may be edited by user community, Granite Devices Oy or it's affiliates do not take any responsibility of the contents of this Wiki. Use information at your own risk. However, Granite Devices staff attempts to review all changes made to this Wiki and keep information trustworthy.

Without written consent, Granite Devices' Products or Intellectual Property shall not be used in situations or installations where living beings, material property, or immaterial property could be harmed by the operation, features or failures of Product. Products may only be used in a way where hazards like moving parts, electric shock, laser radiation, or fire can't be realized even if the content of this Wiki would suggest otherwise.