do - while | with time.0.minutes and time0.seconds

i have realized a mixer for fluids with linuxcnc (linear axis and servos)

i have a question:

the mixer needs to be go up and down a certain time. i tried to use the time module, but everytime i try to use the calculated value in the while clause linuxcnc stops loading or hangs on realoding the program

#<z_mischen_start> = [#<_hal[time.0.minutes]> * 60 + #<_hal[time.0.seconds]>]

G97 S800 M03
o101 do
    #<z_mischen_elapsed> = [[#<_hal[time.0.minutes]> * 60 + #<_hal[time.0.seconds]>] - #<z_mischen_start>]
    G1 X270 F1000
    G1 X250 F1000
o101 while [#<z_mischen_elapsed> LT 4]

any ideas? i'm quite new to linuxcnc ....

thanks a lot !!!

Lars

Reading hal pins in gcode is tricky as you need to sync the interpreter to update the values:
linuxcnc.org/docs/stable/html/gcode/over...gcode:ini-hal-params

Try this:

it does not work, loading linuxcnc hangs an reload program,
endless rotating cursor

it looks like that linuxcnc does somthing with the gcode (syntax check, duration calculation ??) can that swicthed off?