output synchronised to movement

Georg99

I am using Repetier for a plotter.
I have now an inkjet head with 8 jets, each controlled by an output.
According to the distance I want to controll these jets.
eg. to write an "E": would be 1mm all 8 jets - then 3mm jet 1,5,8 - then no jet - then .. next letter

How can I synchronise the movement with the letters?
(speed is very low)
do we have a kind of interrupt of each mm?

Thanks for any help!

Georg99

by thinking about it, I have atleast a first solution:
1) I change in Repetier the E Appendix in the G0 command to controll the 8 jets
(eg 255 for 8 outputs ON for the 8 jets)
2) I write in VisualBasic a GC-Code Generator generating the E-Appendix of G0
The code for the above example to make the letter "E" would be:
G0 X1 E255 - go 1mm with all 8 jets to ON to make the first vertical line of the E
G0 X4 E145 - go 3mm with jet 1,5,8 to On to make the 3 arms of the E
G0 X1 E0 - go 1mm and no jets
The code will tricky for letters with diagonal lines like "N"..then the steps must be smaller maybe 0.5mm.

I assume that setting the outputs is fast enough.
Or will stop the motion between the G0 commands?
Make that sense?

Repetier

No motion will optimize between moves, so that part would be ok. The problem is that motion takes place in a stepper interrupt and there informations like positions and E are lost. There is a field secondSpeed that controls laser intensity in laser mode that is set. You could modify the laser routines to use intensity as inkjet pattern and set it between G moves.

Georg99

thanks for your input - then I make it with the Laser command, like
G0 X1
M5 S255
G0 X4
M5 S145
G0 X5
M5 S0

Thanks!

Repetier

Don't forget to enable "laser" in that case! G0 is then without laser (travel) G1 is with laser.

Georg99

thanks for the hint!