Messages

1

General Mach Discussion / Re: Exact homing

« on: May 11, 2006, 02:57:57 PM »

If you have encoders with the index pulse then this can be used to set exact zero point.

Mach will not do this for you, you have to write a visual basic script for the homing. (Or will it Brian)

Graham.

Graham:

   Do you mean connecting the encoder to the input pins and write a program in VB to get the ABSOLUTE "0" position ?

It sounds good.. I will check if this is possible.

Do you know any Encoder model that have output signals other than the used to connect to the driver ?

Regards,
Victor

2

General Mach Discussion / Re: Exact homing

« on: May 11, 2006, 02:50:53 PM »

SSHNEIDER:  The loop is closed between the driver and the motor, the loop is open between the CNC and the driver. You only send step and direction to the driver form the CNC and the driver/motor dont miss steps because the encoder feedback. But there is NO feedback between the driver and the CNC, the CNC doesnt know if the driver REALLY gets the signals and NEVER knows what exactly position have the encoder.
The problem is that the CNC only knows the starting point, all the movements are based in that point, and that starting position is when the mechanical switch disconects, and it disconects not always in the same exact position because it only have a MECHANICAL precision. The others machines that i have in my job shop (ROMI) seems to stop when the encoder get the ABSOLUTE "0" position, because there is a closed loop between the encoder and the CNC (Siemens).

Regards,
Victor

3

General Mach Discussion / Exact homing

« on: May 10, 2006, 07:43:18 PM »

Hi, im currently designing a Drilling machine (only one axis) for production pourposes on a job shop. Im investigating Mach3 and i want to know if is possible to do and exact homing. This means in the another production machines that i have in my job shop that when the home switch is reached in referencing and then the axis motion changes the direction action stops when a "0" is reached in the encoder on the servomotor not when the switch changes the state. This produce the same exact position every time the machine is referenced. Can i do this using Mach3 ? How ?

Thank you in advance, and excuseme for my poor english.
VNR