64
Manual – IPOSplus®
6
Referencing
Position Detection and Positioning
If a hardware limit switch is reached during reference travel with type 1 or type 2 and the
reference point has not yet been found, the drive turns and continues reference travel in
the other direction.
Once the drive has found the reference point, the following functions are performed:
• The drive stops and switches internally from speed to position control.
• Bit 20 "IPOS Referenced" in H473 StatusWord is set and a binary input, with the
parameter "IPOS REFERENCE", is set.
• Reference offset P900 is transmitted to the actual position value. If the modulo
function is deactivated (P960 = OFF), this is the variable of the encoder H509 - H511
selected in P941. If the modulo function is activated, it is the variable H455
ModActPos.
As of this point, the following formula applies for the machine zero:
Machine zero = reference point + reference offset
The status "referenced" is reset when the inverter is switched off or if error messages
relating to the position measuring system occur (exception: for Hiperface
®
encoders,
see the note below).
For advanced users, MOVIDRIVE
®
offers the option of setting an absolute encoder for
which a new encoder offset is calculated and described at the reference point when the
drive is not enabled and when it is in the safe stop status, for example. It is also possible
to evaluate distance coded encoder systems using complex IPOS
plus®
programming. If
you require support in performing either of these operations, contact SEW service per-
sonnel.
INFORMATION
For Hiperface
®
and SSI absolute encoders, the status "referenced" is always set and
is only reset during reference travel.
INFORMATION
The drive reacts differently when the controller inhibit is set during reference travel, de-
pending on how reference travel was started.
• If reference travel was started via a positive edge at binary input REF.TRAVEL
START or via the non-wait IPOS command
_Go0( ._NW_.. )
; or
GO0...,NW,...
, the reference travel is not continued if the controller inhibit is
reset. To start travel, a positive edge must be set at the input REF. TRAVEL
START.
• If reference travel was started via the wait IPOS command
_Go0( ._W_.. )
; or
GO0...,W,...
, the error message F39 reference travel is generated.
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