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Manufacturer and Profile Specific Objects (CiA DS-406)
8 Manufacturer and Profile Specific Objects (CiA DS-406)
M = Mandatory
O = Optional
Index (h) Object Name Data length Attr. M/O Page
Parameter
2000 VAR
Table 12: Encoder profile range
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8.1 Scaling parameters
Manufacturer and Profile Specific Objects (CiA DS-406)
WARNING !
Danger of personal injury and damage to property exists if the measuring system is restarted after positioning in the de-energized state by shifting of the zero point!
If the number of revolutions is not an exponent of 2 or is >4096, it can occur, if more than 512 revolutions are made in the de-energized state, that the zero point of the multi-turn measuring system is lost!
• Ensure that the quotient of Revolutions Numerator / Revolutions Denominator for a multi-turn measuring system is an exponent of 2 of the group 2
0
, 2
1
, 2
2
…2
12
(1, 2, 4…4096). or
• Ensure that every positioning in the de-energized state for a multi-turn measuring system is within 512 revolutions.
The scaling parameters can be used to change the physical resolution of the measuring system. The measuring system supports the gearbox function for round axes.
This means that the Steps per revolution and the quotient of Revolutions
numerator / Revolutions denominator can be a decimal number.
The position value output is calculated with a zero point correction, the count direction set and the gearbox parameter entered.
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Manufacturer and Profile Specific Objects (CiA DS-406)
8.1.1 Object 2002h: Total measuring range
Defines the total number of steps of the measuring system before the measuring system restarts at zero.
Index
Name
0x2002
Total_Measuring_Range
Object type Array
Data type
Sub-Index
UNSIGNED32
000
Category Mandatory
Description
Access
Number of entries
CONST
PDO mapping no
Default value
Value range
Sub-Index
0x2
0…0x02
001
Description
Category
Data type
Low_Word
Mandatory
UNSIGNED32
Access rw
PDO mapping no
Lower limit
Upper limit
16 steps
CEx-65: 33 554 432 steps (25 bit)
COx-65: 0 steps (low fraction)
33 554 432 steps Default value
Sub-Index
Description
002
High_Word
Category
Data type
Access
Mandatory
UNSIGNED32 rw
PDO mapping no
Lower limit 0 steps
Upper limit
CEx-65: 0 steps
COx-65: 16 steps (high fraction)
Default value 0 steps
The actual upper limit for the measurement length to be entered in steps is dependent on the measuring system version and can be calculated with the formula below. As the value "0" is already counted as a step, the end value = measurement length in steps - 1.
Total measuring range = Steps per revolution * Number of revolutions
To calculate, the parameters steps/rev. and the number of revolutions can be read on the measuring system nameplate.
Total measuring range Low_Word Total measuring range High_Word
Byte 0 Byte 1 Byte 2 Byte 3 Byte 0 Byte 1 Byte 2 Byte 3
CEx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
- - - -
COx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
2
39
to 2
32
2
47
to 2
40
2
55
to 2
48
2
63
to 2
56
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Manufacturer and Profile Specific Objects (CiA DS-406)
8.1.2 Object 2000-2001h: Number of revolutions Numerator / Divisor
Together, these two parameters define the Number of revolutions before the measuring system restarts at zero.
As decimal numbers are not always finite (as is e.g. 3.4), but they may have an infinite number of digits after the decimal point (e.g. 3.43535355358774...) the number of revolutions is entered as a fraction.
Index 0x2000
Description
Data type
Category
Access
PDO mapping
Number_Of_Revolution-numerator
UNSIGNED32
Mandatory rw
No
Lower limit
Upper limit
1
256000
Default 4096
Index 0x2001
Description
Data type
Category
Number_Of_Revolution-divisor
UNSIGNED32
Optional rw
Access
PDO mapping
Lower limit
No
1
Upper limit
16384
Default 1
Formula for gearbox calculation:
Number of Revolutions numerator
Total measuring range = Steps per revolution *
Number of Revolutions denominator
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Manufacturer and Profile Specific Objects (CiA DS-406)
If it is not possible to enter parameter data in the permitted ranges of numerator and denominator, the attempt must be made to reduce these accordingly. If this is not possible, it may only be possible to represent the decimal number affected approximately. The resulting minor inaccuracy accumulates for real round axis applications (infinite applications with motion in one direction).
A solution is e.g. to perform adjustment after each revolution or to adapt the mechanics or gearbox accordingly.
The parameter "Steps per revolution" may also be decimal number, however the
"Total measuring range" may not. The result of the above formula must be rounded up or down. The resulting error is distributed over the total number of revolutions programmed and is therefore negligible.
Preferably for linear axes (forward and backward motions):
The parameter "Revolutions denominator" can be programmed as a fixed value of
"1". The parameter "Revolutions numerator" is programmed slightly higher than the required number of revolutions. This ensures that the measuring system does not generate a jump in the actual value (zero transition) if the distance travelled is exceeded. To simplify matters the complete revolution range of the measuring system can also be programmed.
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Manufacturer and Profile Specific Objects (CiA DS-406)
The following example serves to illustrate the approach:
Given:
-
-
Measuring system with 4096 steps/rev. and max. 4096 revolutions
Resolution 1/100 mm
-
-
-
-
-
-
Ensure the measuring system is programmed in its full resolution and total measuring length (4096x4096):
Total number of steps = 16777216,
Revolutions numerator = 4096
Revolutions denominator = 1
Set the mechanics to be measured to the left stop position
Set measuring system to "0" using the adjustment
Set the mechanics to be measured to the end position
Measure the mechanical distance covered in mm
Read off the actual value of the measuring system from the controller connected
-
-
Assumed:
Distance covered = 2000 mm
Measuring system actual position after 2000 mm = 607682 steps
Derived:
Number of revolutions covered = 607682 steps / 4096 steps/rev.
=
Number of mm / revolution = 2000 mm / 148.3598633 revs. = 13.48073499mm / rev.
For 1/100mm resolution this equates to a Number of steps per revolution of 1348.073499
Required programming:
Number of Revolutions numerator = 4096
Number of Revolutions denominator = 1
Number of revolutions numerator
Total number of steps = Number of steps per revolution *
Number of revolutions denominator
4096 revolutions numerator
= 1348.073499 steps / rev. *
1 revolution denominator
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Manufacturer and Profile Specific Objects (CiA DS-406)
8.2 Object 2003h: Preset value
The object defines the position value for the preset function and is used to set the measuring system value to any position value within the range of 0 to measuring
length in increments –1. The preset function is executed using Object 2004h: Set
Object type Array Index
Name
Data type
Sub-Index
Description
0x2003
Preset_Value
UNSIGNED32
000
Number of entries
Access CONST
PDO mapping no
Default value
Value range
Sub-Index
Description
Upper limit
Default value
Sub-Index
Description
0x2
0…0x02
Category
Data type
Access rw
PDO mapping no
Lower limit
001
Low_Word
Mandatory
UNSIGNED32
0
CEx-65: 33 554 432 steps (25 bit)
COx-65: 0 steps (low fraction)
0
002
High_Word
Category
Data type
Access rw
PDO mapping no
Lower limit
Mandatory
UNSIGNED32
Upper limit
0
CEx-65: 0 steps
COx-65: 16 steps (high fraction)
0 Default value
Category Mandatory
Preset Low_Word Preset High_Word
Byte 0 Byte 1 Byte 2 Byte 3 Byte 0 Byte 1 Byte 2 Byte 3
CEx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
- - - -
COx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
2
39
to 2
32
2
47
to 2
40
2
55
to 2
48
2
63
to 2
56
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8.3 Object 2004h: Set Preset
Manufacturer and Profile Specific Objects (CiA DS-406)
Danger of physical injury and damage to property due to an actual value jump during execution of the preset adjustment function!
WARNING!
• The preset adjustment function should only be executed when the measuring system is stationary, or the resulting actual value jump must be permitted by both the program and the application!
The preset function is used to set the measuring system value to any position value within the range of 0 to measuring length in increments –1.
The output position value is set to the Preset value parameter, if the positive edge of bit 2
0
is detected.
The preset value will be defined in Object 2003h: Preset value, see page 174.
Index 0x2004
Description
Data type
Category
Set_Preset
UNSIGNED8
Optional
Access
PDO mapping
Value
8.4 Object 2005h: Operating parameters
The object with index 2005h supports only the function for the code sequence.
The code sequence defines whether increasing or decreasing position values are output when the measuring system shaft rotates clockwise or counter clockwise as seen on the shaft.
Index
Name rw
No
-
0x2005
Operating_Parameters
Object type VAR
Data type
Value range
UNSIGNED8
Bit 0 = 0: Position increasing clockwise
Bit 0 = 1: Position decreasing clockwise
Default value 0
Category
Access
Optional rw
8.5 Object 2006h: Accept parameters
With write access to this object, the measuring system accepts the parameters in the non-volatile memory (EEPROM).
Index
Name
0x2006
Accept_Parameters
PDO mapping no
Object type VAR
Data type UNSIGNED8
Value range not relevant
Default value 0
Category
Access
Optional rw
PDO mapping no
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Manufacturer and Profile Specific Objects (CiA DS-406)
8.6 Object 2007h: Position value
With this object it is possible to read the contents of the mapping object “Object
3100h: Mapping”, also in acyclic data exchange over a SDO request.
Index
Name
0x2007
Position_Value
Object type Array
UNSIGNED32 Category Optional Data type
Sub-Index
Description
000
Number of entries
Access CONST
PDO mapping no
Default value
Value range
Sub-Index
0x2
0…0x02
Description
Category
Data type
Access
001
Low_Word
Optional
UNSIGNED32 ro
PDO mapping no
Default value
Value range
Sub-Index
Description
Category
Data type
Access
0
0…0xFF FF FF FF
002
High_Word
Optional
UNSIGNED32 ro
PDO mapping no
Default value 0
Value range 0…0xFF FF FF FF
Position Low_Word Position High_Word
Byte 0 Byte 1 Byte 2 Byte 3 Byte 0 Byte 1 Byte 2 Byte 3
CEx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
- - - -
COx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
2
39
to 2
32
2
47
to 2
40
2
55
to 2
48
2
63
to 2
56
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Manufacturer and Profile Specific Objects (CiA DS-406)
8.7 Object 3100h: Mapping
The object defines the output position value for the mapping parameter object 1A00
(Transmit-PDO).
Index
Name
0x3100
Mapping
Object type Array
UNSIGNED32 Category Optional Data type
Sub-Index 000
Description
Access
Number of entries
CONST
PDO mapping no
Default value 0x2
0…0x02 Value range
Sub-Index
Description
001
Position_Low
Category
Data type
Optional
UNSIGNED32
Access ro
PDO mapping yes
Default value
Value range
Sub-Index
0
0…0xFF FF FF FF
Description
Category
Data type
Access
002
Position_High
Optional
UNSIGNED32 ro
PDO mapping yes
Default value
Value range
0
0…0xFF FF FF FF
Position_Low Position_High
Byte 0 Byte 1 Byte 2 Byte 3 Byte 0 Byte 1 Byte 2 Byte 3
CEx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
- - - -
COx-65
2
7
to 2
0
2
15
to 2
8
2
23
to 2
16
2
31
to 2
24
2
39
to 2
32
2
47
to 2
40
2
55
to 2
48
2
63
to 2
56
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© TR-Electronic GmbH 2008, All Rights Reserved
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