Siemens SINUMERIK 840D sl Function Manual page 89

03.06
"Axis safely referenced" state
In order to reach the axis state "axis safely referenced", the axis state "axis refer-
enced" must have been reached, and either
S the user confirms the current position using the user agreement (see Subsec-
tion 5.4.4 "User agreement"
or
S a saved and set user agreement and saved stop position when the system was
powered-down must exist. The position associated with the saved data must
match the current position within a tolerance window. This is checked both in
the drive and in the NC.
(see Fig. 5-5 "Axis states when referencing").
The axis state "axis safely referenced" is displayed using the SGA "axis safely ref-
erenced". A safety-relevant position evaluation can only be carried-out for the SE
and SN functions after this state has been reached.
Saved user agreement
The state of the user agreement function is saved in non-volatile memories. This
saved user agreement forms, together with the stop position, also saved in a non-
volatile fashion the prerequisite for the axis state "axis safely referenced".
Saved stop position
The saved stop position data is combined with the permanently saved user agree-
ment to form the previous history.
The following must be noted when the stop position is saved:
The following applies when SE/SN is active:
S The stop position is also cyclically saved.
S If the axis is moved with the system powered-down, then the saved stop posi-
tion no longer matches the current position.
As described under "axis safely referenced" the "axis safely referenced" state can
also be achieved using a saved and set user agreement and a saved stop position.
The following conditions must be fulfilled:
S The saved user agreement must be available.
S The difference between the "reference position" (power-on position with abso-
lute measuring systems or reference position for incremental measuring sys-
tems) and the saved stop position (including the traversing distance to the refer-
ence point with ERN) must be within a tolerance window specified using the
appropriate machine data.
© Siemens AG, 2006. All rights reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
Basics on the Safety Functions Integrated in the System/Drive
5.4 Actual value conditioning
5-89