SEW-Eurodrive MOVISAFE DCS21B

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Manual – MOVIDRIVE® MDX61B Safety Module Option MOVISAFE® DCS..B
6
Fieldbus connection via PROFIsafe
Startup
6.7.3 Scaling the position values in the DCS21B/22B option
With the DCS21B/22B option, you can transmit the internal position to a safety control-
ler. You can also have the safety controller specify target positions for the DCS21B/22B
option. For more information, refer to chapter "PROFIsafe process image".
Internally, the DCS21B/22B 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/22B option lets you scale the current position
values of the application or the target positions using a factor. The values can be scaled
using factors 1, 10, 100, 1000 or 10 000. In this case, all the values transmitted by the
DCS21B/22B option to the safety controller will be divided by this factor. Target positions
sent from the safety controller to the DCS21B/22B option will be multiplied by this factor.
For conversion of the position values, also the Pos_Factor (see Encoder information
field) has to be taken into account in addition to the divisor factor because the
DCS21B/22B option operates internally always with the highest possible resolution. For
further 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 cannot be processed in the safety controller because it
cannot be mapped in a 16-bit value (65536 dec).
This can be rectified by activating the scaling factor of the DCS21B option.
• Resolution in the DCS21B/22B 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
The scaling factor used must also be taken into account to ensure that the safety con-
troller uses the same unit as that of the DCS21B option to further process the position
value.
Unit selected in the DCS21B option = mm
Max. measuring section = 100 000 mm
Pos_Factor (encoder information 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