SEW-Eurodrive MOVISAFE DCS B Series

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Manual – MOVIDRIVE® MDX61B Safety Module MOVISAFE® DCS..B Option
6
Fieldbus connection via PROFIsafe
Startup
6.7.3 Scaling the position values in the DCS21B option
With the DCS21B option, you can transmit the internal position to a safety controller.
You can also have the safety controller specify target positions for the DCS21B option.
For more information, refer to chapter "PROFIsafe process image".
Internally, the DCS21B option works with positions in a 32-bit number format. It might
be necessary to limit the values to 16 bits for further processing depending on the safety
controller in use. The DCS21B option lets you scale the current position values of the
application or the target positions using a factor. The values can be scales with factors
1, 10, 100, 1000 or 10 000. In this case, all the values transmitted by the DCS21B option
to the safety controller will be divided by this factor. Target positions sent from the safety
controller to the DCS21B option will be multiplied by this factor.
As the DCS21B internally always works with the highest possible resolution, you have
to take into account not only of the divisor factor when converting the position values but
also the Pos_Factor (see encoder info field). For more information on the Pos_Factor,
refer to chapter "Configuring the measuring sections".
Example A maximum measuring distance of 100 000 mm (100 m) is to be monitored in an appli-
cation. The value 100 000 mm can not be processed by the safety controller because
this value can not be mapped to a 16-bit value (65536 dec).
Activating the scaling factor in the DCS21B option can rectify this.
• Resolution in the DCS21B option
• Max. position value to be transmitted
As the safety controller can maximally process 16-bit values internally but the value
to be transmitted is much greater, this value has to be adjusted accordingly using the
scaling factor.
• Position value to be transmitted after the scaling
Unit selected in the DCS21B option = mm
Max. measuring section = 100 000 mm
Pos_Factor (encoder info field) = 10
Scaling factor = 1000
Higher-level controller = max. 16-bit values
4142690955
4142695947
4142725643
Resolution DCS B
Selected unit in the DCS B
Pos Factor
mm
21
21
1
==
_
00
Position DCS B
Max. measuring section
Resolution DCS B
m
21
21
100000
= =
mm
mm
mm
1
10
1000000 1000000
1
10
=
≙
Position in controller
Position DCS B
Scaling factor
==
21 1 00
00000
1000
10000=
00
I