many thanks. figured out with your help. works as it should.

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool on Sat Jun 02 2018 22:48:38 GMT+0300 (RTZ 2 (зима))
G91 ; relative positioning
G1 S1 Z295 F6000 ; move Z up until the switch triggers
G1 Z-10 F6000 S2 ; lift Z relative to current position
G1 S1 Z295 F500 ; move Z up until the switch triggers
G92 Z0.2 ; set Z position to trigger height

; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 Z5 F100 S2 ; lift Z relative to current position
G90 ; absolute positioning

HomeZ action is correct, but then ...

Hi. I tried configure my Ultimaker. Z axis on home action move to the endstop and set position ftom config. But ufter any G command for X,Y or Z axis bed moving to zero position and on the next G command to max position and so on the circle. During print simulation or real print beg any time go up and down.
; Configuration file for Duet WiFi (firmware version 1.20 or newer)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool on Sat Jun 02 2018 22:48:38 GMT+0300 (RTZ 2 (зима))

;M111 S0 ; Debug off
M575 P1 B57600 S1 ; Set auxiliary serial port baud rate and require checksum (for PanelDue)

; General preferences
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves
M555 P1 ; Set firmware compatibility to look like RepRapFirmare
M667 S0 ; Select Cartesian
G21 ;Set in mm

; Drives
M569 P0 S1 ; Drive 0 goes backwards
M569 P1 S0 ; Drive 1 goes backwards
M569 P2 S1 ; Drive 2 goes backwards
M569 P3 S0 ; Drive 3 goes forwards
M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
M92 X80 Y80 Z400 E377 ; Set steps per mm
M566 X900 Y900 Z12 E120 ; Set maximum instantaneous speed changes (mm/min)
M203 X18000 Y18000 Z2400 E2700 ; Set maximum speeds (mm/min)
M201 X2500 Y2500 Z250 E250 ; Set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800 I20 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z294 S1 ; Set axis minima
M208 X213 Y199 Z0 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 S0 ; Set active low endstops
M574 Z2 S1 ; Set active high endstops

; Z-Probe
M558 P5 X0 Y0 Z0 H5 F120 T6000 I1 ; Set Z probe type to switch and the dive height + speeds
G31 P600 X0 Y0 Z0.4 ; Set Z probe trigger value, offset and trigger height
M557 X15:198 Y15:185 S20 ; Define mesh grid

; Heaters
M305 P0 X201 ; Configure thermocouple for heater 0
M143 H0 S120 ; Set temperature limit for heater 0 to 120C
M301 H1 S1.00 P10 I0.1 D200 T0.4 W180 B30 ; Use PID on bed heater (may require further tuning)
M305 P1 X200 ; Configure thermocouple for heater 1
M143 H1 S280 ; Set temperature limit for heater 1 to 280C

; Fans
M106 P0 S1 I0 F500 H1 T45 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P1 S0 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P2 S0.1 I0 F500 H-1 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned off

; Tools
M563 P0 D0 H1 ; Define tool 0
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

; Automatic saving after power loss is not enabled

; Custom settings are not configured

; Miscellaneous
T0 ; Select first tool
;M501 ; Run config-override.g

; Network
M550 PDuetUltimaker ; Set machine name
M586 P0 S1 ; Enable HTTP
M586 P1 S0 ; Disable FTP
M586 P2 S0 ; Disable Telnet
M552 S1 ; Enable network