Siemens SINUMERIK FM-NC Installation And Startup Manual page 122

6 Assigning Parameters to the Control and the PLC Program
6.9 Axes and spindles
Readjustment of
absolute encoder
Sequence of
operations
6-122
Note
In all other cases, the user him/herself is responsible for ensuring that
MD 34210: ENC_REFP_STATE switches to "0" or "1" and for readjusting the
encoder.
In the case of "Position back-up after Power Off", setting REFP_STATE=1
merely causes the setting to change to "2" if referencing has already taken
place.
To end this mode, REFP_STATE must be set to 0. This Referenced/Adjusted
state will otherwise remain valid forever, even after REFP_MODE has been
changed and Power Off.
The following MDs must be noted before the encoder is adjusted:
MD 34200: ENC_REFP_MODE=0 (with absolute encoder: Transfer of
REFP_SET_POS)
MD 34220: ENC_ABS_TURNS_MODULO (required only for rotary axes)
1. Set MD 30240: ENC_TYPE=4.
2. Set MD 34200: ENC_REFP_MODE=0.
3. Execute NCK reset.
4. Move axis to reference position, setting MD 34010:
REFP_CAM_DIR_IS_MINUS according to the approach direction. (If the
axis is traversed in the negative direction towards the reference position,
then MD 34010 must be set to 1.)
5. Set MD 34100: REFP_SET_POS to the actual value of the reference posi-
tion.
6. Set MD 34210: ENC_REFP_STATE to 1 to activate the adjusted settings.
7. Select the adjusted axis on the MCP and press RESET button on MCP.
8. Select JOG/REF mode, issue feed enabling command for axis.
9. The adjustment process must be initiated with traversing key "+" or "–" ac-
cording to MD 34010: REFP_CAM_DIR_IS_MINUS and the direction of ap-
proach towards the reference position. (Backlash has been eliminated.) The
axis does not traverse. Instead, the offset between the correct actual value
(reference position) and the actual value supplied by the encoder is entered
in MD 34090: REFP_MOVE_DIST_CORR. The current actual value ap-
pears in the basic display, the axis signals "referenced". The value "2" is
entered in MD 34210 as the result.
Example:
MD 34010 = 1 (negative) and reference position has been traversed in neg-
ative direction. In this case, the "–" key on the MCP must also be pressed.
SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
 Siemens AG 2000 All Rights Reserved
04.00
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