WAGO I/O System 750 Series User manual

Fieldbus Independent
I/O Modules
Incremental Encoder Interfaces
750-631 (/xxx-xxx)
Manual
Version 1.1.1

ii • General
WAGO-I/O-SYSTEM 750
I/O Modules
Copyright 2008 by WAGO Kontakttechnik GmbH & Co. KG
All rights reserved.
WAGO Kontakttechnik GmbH & Co. KG
Hansastraße 27
D-32423 Minden
Phone: [phone] – 0
Fax: [phone] – 1 69
E-Mail: [email protected]
Web: http://www.wago.com
Technical Support
Phone: [phone] – 5 55
Fax: [phone] – 85 55
E-Mail: [email protected]
Every conceivable measure has been taken to ensure the correctness and com-
pleteness of this documentation. However, as errors can never be fully ex-
cluded, we would appreciate any information or ideas at any time.
E-Mail: [email protected]
We wish to point out that the software and hardware terms as well as the
trademarks of companies used and/or mentioned in the present manual are
generally trademark or patent protected.

Content •iii
WAGO-I/O-SYSTEM 750
I/O Modules
Content
1Important Notes ..........................................................................................5
1.1 Legal Bases...............................................................................................5
1.1.1 Copyright ............................................................................................. 5
1.1.2 Personnel Qualifications......................................................................5
1.1.3 Use of the 750 Series in Compliance with Underlying Provisions .....6
1.1.4 Technical Condition of Specified Devices .......................................... 6
1.2 Standards and Guidelines for Operating the 750 Series...........................7
1.3 Symbols....................................................................................................8
1.4 Safety Information....................................................................................9
1.5 Font Conventions ................................................................................... 10
1.6 Number Notation....................................................................................10
1.7 Scope ......................................................................................................11
2I/O Modules...............................................................................................12
2.1 Special Modules ..................................................................................... 12
2.1.1 Overview Incremental Encoder Interfaces 750-631 (/xxx-xxx)........12
2.1.2 750-631(750-631/000-001) [Incremental Encoder Interface] ...........13
2.1.2.1 Variations...................................................................................... 13
2.1.2.2 View..............................................................................................13
2.1.2.3 Description.................................................................................... 13
2.1.2.4 Display Elements .......................................................................... 14
2.1.2.5 Schematic Diagram....................................................................... 15
2.1.2.6 Technical Data .............................................................................. 16
2.1.2.7 Functional Description..................................................................17
2.1.2.8 Process Image ............................................................................... 18
2.1.3 750-631/000-004 [Incremental Enc./ RS422] ...................................21
2.1.3.1 View..............................................................................................21
2.1.3.2 Description.................................................................................... 21
2.1.3.3 Display Elements .......................................................................... 22
2.1.3.4 Schematic Diagram....................................................................... 23
2.1.3.5 Technical Data .............................................................................. 24
2.1.3.6 Functional Description..................................................................26
2.1.3.7 Process Image ............................................................................... 27
2.1.4 750-631/000-010, 750-631/000-011 [Incremental Encoder Interface]31
2.1.4.1 Variations...................................................................................... 31
2.1.4.2 View..............................................................................................31
2.1.4.3 Description.................................................................................... 31
2.1.4.4 Display Elements .......................................................................... 33
2.1.4.5 Schematic Diagram....................................................................... 34
2.1.4.6 Technical Data .............................................................................. 35
2.1.4.7 Functional Description..................................................................37
2.1.4.8 Process Image ............................................................................... 38
2.1.4.9 Connection Variations .................................................................. 42
2.1.4.9.1 Incremental Encoder with RS422 Output (Variation A)..........42
2.1.4.9.2 Incremental Encoder with 24 V Push-Pull Output (Variation B)42

iv •Content
WAGO-I/O-SYSTEM 750
I/O Modules
2.1.4.9.3 Incremental Encoder with non-equivalent 24 V Push-Pull
Output (Variation C) ................................................................43
2.1.4.9.4 Incremental Encoder with 5 V Push-Pull Output (Variation D)43
3Use in Hazardous Environments .............................................................44
3.1 Marking Configuration Examples..........................................................45
3.1.1 Marking for Europe according to CENELEC and IEC .....................45
3.1.2 Marking for America according to NEC 500 ....................................48
3.2 Installation Regulations.......................................................................... 49
3.2.1 Special Conditions for Safe Operation of the ATEX and IEC Ex (acc.
DEMKO 08 ATEX 142851X and IECEx PTB 07.0064).................. 50
3.2.2 Special conditions for safe use (ATEX Certificate TÜV 07 ATEX
554086 X) ..........................................................................................51
3.2.3 Special conditions for safe use (IEC-Ex Certificate TUN 09.0001 X)53
3.2.4 Special conditions for safe use (ATEX Certificate DEKRA
11ATEX0203 X) ...............................................................................55
3.2.5 ANSI/ISA 12.12.01 ........................................................................... 56

Important Notes •5
Legal Bases
WAGO-I/O-SYSTEM 750
I/O Modules
1 Important Notes
This section includes an overall summary of the most important safety
requirements and notes that are mentioned in each individual section. To
protect your health and prevent damage to devices as well, it is imperative to
read and carefully follow the safety guidelines.
1.1 Legal Bases
1.1.1 Copyright
This Manual, including all figures and illustrations, is copyright-protected.
Any further use of this Manual by third parties that violate pertinent copyright
provisions is prohibited. Reproduction, translation, electronic and
phototechnical filing/archiving (e.g., photocopying) as well as any
amendments require the written consent of WAGO Kontakttechnik GmbH &
Co. KG, Minden, Germany. Non-observance will involve the right to assert
damage claims.
WAGO Kontakttechnik GmbH & Co. KG reserves the right to provide for any
alterations or modifications that serve to increase the efficiency of technical
progress. WAGO Kontakttechnik GmbH & Co. KG owns all rights arising
from the granting of patents or from the legal protection of utility patents.
Third-party products are always mentioned without any reference to patent
rights. Thus, the existence of such rights cannot be excluded.
1.1.2 Personnel Qualifications
The use of the product described in this Manual requires special personnel
qualifications, as shown in the following table:
Activity Electrical specialist Instructed
personnel*)
Specialists**) having
qualifications in PLC
programming
Assembly X X
Commissioning X X
Programming X
Maintenance X X
Troubleshooting X
Disassembly X X
*) Instructed persons have been trained by qualified personnel or electrical specialists.
**) A specialist is a person, who – thanks to technical training – has the qualification, know-
ledge and expertise to meet the required specifications of this work and to identify any po-
tential hazardous situation in the above listed fields of activity.

6 •Content
Legal Bases
WAGO-I/O-SYSTEM 750
I/O Modules
All responsible persons have to familiarize themselves with the underlying
legal standards to be applied. WAGO Kontakttechnik GmbH & Co. KG does
not assume any liability whatsoever resulting from improper handling and
damage incurred to both WAGO´s own and third-party products by
disregarding detailed information in this Manual.
1.1.3 Use of the 750 Series in Compliance with Underlying
Provisions
Couplers, controllers and I/O modules found in the modular WAGO-I/O-
SYSTEM 750 receive digital and analog signals from sensors and transmit
them to the actuators or higher-level control systems. Using programmable
controllers, the signals can also be (pre-)processed.
The components have been developed for use in an environment that meets
the IP20 protection class criteria. Protection against finger injury and solid
impurities up to 12.5 mm diameter is assured; protection against water damage
is not ensured. Unless otherwise specified, operation of the components in wet
and dusty environments is prohibited.
1.1.4 Technical Condition of Specified Devices
The components to be supplied Ex Works, are equipped with hardware and
software configurations, which meet the individual application requirements.
Changes in hardware, software and firmware are permitted exclusively within
the framework of the various alternatives that are documented in the specific
manuals. WAGO Kontakttechnik GmbH & Co. KG will be exempted from
any liability in case of changes in hardware or software as well as to non-
compliant usage of components.
Please send your request for modified and new hardware or software
configurations directly to WAGO Kontakttechnik GmbH & Co. KG.

Important Notes •7
Standards and Guidelines for Operating the 750 Series
WAGO-I/O-SYSTEM 750
I/O Modules
1.2 Standards and Guidelines for Operating the 750 Series
Please adhere to the standards and guidelines required for the use of your
system:
The data and power lines shall be connected and installed in compliance
with the standards required to avoid failures on your system and to
substantially minimize any imminently hazardous situations resulting in
personal injury.
For assembly, start-up, maintenance and troubleshooting, adhere to the
specific accident prevention provisions which apply to your system (e.g.
BGV A 3, "Electrical Installations and Equipment").
Emergency stop functions and equipment shall not be made ineffective.
See relevant standards (e.g. DIN EN 418).
The equipment of your system shall be conform to EMC guidelines so that
any electromagnetic interferences will be eliminated.
Operating 750 Series components in home applications without further
measures is permitted only if they meet the emission limits (emissions of
interference) in compliance with EN 61000-6-3. You will find the detailed
information in section "WAGO-I/O-SYSTEM 750" "System
Description" "Technical Data".
Please observe the safety precautions against electrostatic discharge in
accordance with DIN EN 61340-5-1/-3. When handling the modules,
please ensure that environmental factors (persons, working place and
packaging) are well grounded.
The valid standards and guidelines applicable for the installation of switch
cabinets shall be adhered to.

8 •Content
Symbols
WAGO-I/O-SYSTEM 750
I/O Modules
1.3 Symbols
Danger
Always observe this information to protect persons from injury.
Warning
Always observe this information to prevent damage to the device.
Attention
Marginal conditions that must always be observed to ensure smooth and
efficient operation.
ESD (Electrostatic Discharge)
Warning of damage to the components through electrostatic discharge.
Observe the precautionary measure for handling components at risk of
electrostatic discharge.
Note
Make important notes that are to be complied with so that a trouble-free and
efficient device operation can be guaranteed.
Additional Information
References to additional literature, manuals, data sheets and internet pages.

Important Notes •9
Safety Information
WAGO-I/O-SYSTEM 750
I/O Modules
1.4 Safety Information
When connecting the device to your installation and during operation, the
following safety notes must be observed:
Danger
The WAGO-I/O-SYSTEM 750 and its components are an open system. It
must only be assembled in housings, cabinets or in electrical operation rooms.
Access is only permitted via a key or tool to authorized qualified personnel.
Danger
All power sources to the device must always be switched off before carrying
out any installation, repair or maintenance work.
Warning
Replace defective or damaged device/module (e.g. in the event of deformed
contacts), as the functionality of field bus station in question can no longer be
ensured on a long-term basis.
Warning
The components are not resistant against materials having seeping and
insulating properties. Belonging to this group of materials is: e.g. aerosols,
silicones, triglycerides (found in some hand creams). If it cannot be ruled out
that these materials appear in the component environment, then the
components must be installed in an enclosure that is resistant against the
above mentioned materials. Clean tools and materials are generally required
to operate the device/module.
Warning
Soiled contacts must be cleaned using oil-free compressed air or with ethyl
alcohol and leather cloths.
Warning
Do not use contact sprays, which could possibly impair the functioning of the
contact area.
Warning
Avoid reverse polarity of data and power lines, as this may damage the
devices.
ESD (Electrostatic Discharge)
The devices are equipped with electronic components that may be destroyed
by electrostatic discharge when touched.

10 •Content
Font Conventions
WAGO-I/O-SYSTEM 750
I/O Modules
Warning
For components with ETHERNET/RJ-45 connectors:
Only for use in LAN, not for connection to telecommunication circuits.
1.5 Font Conventions
italic Names of paths and data files are marked in italic-type.
e.g.: C:\Programs\WAGO-IO-CHECK
italic Menu items are marked in italic-type, bold letters.
e.g.: Save
\ A backslash between two names characterizes the selection of a
menu point from a menu.
e.g.: File \ New
END Pushbuttons are marked as bold with small capitals
e.g.: ENTER
< > Keys are marked bold within angle brackets
e.g.: <F5>
Courier The print font for program codes is Courier.
e.g.: END_VAR
1.6 Number Notation
Number code Example Note
Decimal 100 Normal notation
Hexadecimal 0x64 C notation
Binary '100'
'0110.0100'
In quotation marks,
nibble separated with dots (.)

Important Notes •11
Scope
WAGO-I/O-SYSTEM 750
I/O Modules
1.7 Scope
This manual describes the Digital Input Module 750-631 Incremental
Encoder Interface of the modular WAGO-I/O-SYSTEM 750.
Handling, assembly and start-up are described in the manual of the Fieldbus
Coupler. Therefore this documentation is valid only in the connection with the
appropriate manual.

12 •Overview Incremental Encoder Interfaces 750-631 (/xxx-xxx)
Variations
WAGO-I/O-SYSTEM 750
I/O Modules
2 I/O Modules
2.1 Special Modules
2.1.1 Overview Incremental Encoder Interfaces 750-631 (/xxx-xxx)
I/O module 750-631 750-631/
000-001 750-631/ 000-004 750-631/ 000-010 750-631/ 000-011
Function Incremental
encoder
interface
Incremental
encoder
interface,
single report
Incremental
encoder
interface,
RS422
Incremental
encoder
interface
Incremental
encoder
interface,
single report
Sensor input differential differential differential single
ended,
differential
single
ended,
differential
Digital input Latch, gate Latch, gate Latch, gate,
ext. error
Latch, gate,
ext. error
Latch, gate,
ext. error
sensor supply
voltage
DC 5 V DC 5 V DC 5 V
(RS422)
DC 5 V ...
24 V
DC 5 V ...
24 V
Report 4-fold single 4-fold 4-fold single
Data width 32 bit 32 bit 32 bit 32 bit 32 bit
Remark No longer
available
No longer
available

750-631(750-631/000-001) [Incremental Encoder Interface] •13
Variations
WAGO-I/O-SYSTEM 750
I/O Modules
2.1.2 750-631(750-631/000-001) [Incremental Encoder Interface]
2.1.2.1 Variations
Item-No. Designation Description
750-631 Increment.Enc. Incremental Encoder Interface,
4-fold report
750-631/000-001 Increment.Enc./
single report
Incremental Encoder Interface,
single report
2.1.2.2 View
Ue Uo
--
SS
15 16
C
D
B
A
CC
LG
13 14
C
D
B
A
750-631
BB
AA
++
A
A
B
B
C
C
B
A
C
Gate
Latch
0V
24V
5V
0V
Gate
Latch
Fig. 2.1.2-2: View g063100e
2.1.2.3 Description
This module is an interface for the connection of any incremental encoder.
The transmitter can be directly supplied from the Ue and U0 terminations of
the module.
The shield (screen) is directly connected to the carrier rail.
A 16 bit counter with quadrature encoder interface as well as a 16 bit latch for
the zero impulse can be read, set, or enabled. The count of the counter will be
transmitted fast and interference-free over the fieldbus to the PC, PLC, or NC.
A counter lock-out is possible using input Gate.
Individual green status LEDs indicate the operating status of the module and
the signal status of the A, B and C as well as latch and gate inputs.

14 •750-631(750-631/000-001) [Incremental Encoder Interface]
Display Elements
WAGO-I/O-SYSTEM 750
I/O Modules
Any configuration of the specialty modules is possible when designing the
fieldbus node. Grouping of module types is not necessary.
Attention
This module has no power contacts. For field supply to downstream I/O
modules, a supply module will be needed.
The module 750-631 and its variations can be used with all
couplers/controllers of the WAGO-I/O-SYSTEM 750 (except for the economy
types 750-320, -323, -324 and -327).
This description is valid for the XXXX2B1A... and XXXX2B1B... hardware
and software versions. The version is specified in the manufacturing number,
which is part of the lateral marking on the module.
2.1.2.4 Display Elements
LED Channel State Function
off Signal (0)A1 A
green Signal (1)
off Signal (0)B1 B
green Signal (1)
off Signal (0)C1 C
green Signal (1)
off Signal (0)B2 Latch
green Signal (1)
off No operational readiness or the
internal data bus
communication is interrupted
C2 Function
green Operational readiness and
trouble-free internal data bus
communication
off Signal (0)
15 16
C
D
B
A
13 14
C
D
B
A
B1
A1
C1 D2
C2
B2
Fig. 2.1.2-2: Display
Elements g063102x
D2 Gate
green Signal (1)

750-631(750-631/000-001) [Incremental Encoder Interface] •15
Schematic Diagram
WAGO-I/O-SYSTEM 750
I/O Modules
2.1.2.5 Schematic Diagram
24V
0V
Ue/U
0
Latch/Gate
Latch/Gate
Logic
A/A
A/A
_
_
B/B B/B
__
C/C
C/C
_
_
Shield
(screen)
A,B,C
Gate,Latch
Function
1
2
3
4
5
6
7
8
750-631
1
2
3
4
5
6
7
8
Fig. 2.1.2-1: Schematic Diagram g063101e

16 •750-631(750-631/000-001) [Incremental Encoder Interface]
Technical Data
WAGO-I/O-SYSTEM 750
I/O Modules
2.1.2.6 Technical Data
Module Specific Data
Sensor connection A, /A, B, /B, C, /C (/A, /B, /C are inversed)
Current consumption (internal) 25 mA
Signal voltage A, B, C, /A, /B, /C (0) U ≤2.0 V
(1) U ≥5.0 V
Signal voltage Latch, Gate (0) U ≤2.0 V
(1) U ≥11.0 V
Sensor power supply DC 5 V
Sensor output current max. 200 mA
Counter 16 bits binary
Operating frequency 470 kHz
Quadrature decoder 4-fold report (750-631),
single report (750-631/000-001)
Zero impulse latch 16 bits
Commands read, set, enable
Voltage supply DC 24 V (-15 % ... +20 %)
Current consumption typ. 6 mA without sensor
Internal bit width 1 x 32 bits
1 x 8 bits control/status
1 x 8 bits reserved
Isolation 500 V (System/Supply)
Dimensions W x H* x L
* from upper edge of 35 DIN rail
24 mm x 64 mm x 100 mm
Weight ca. 105 g
Approvals
CULUS (UL508)
CULUS (ANSI/ISA 12.12.01) Class I Div2 ABCD T4
Conformity Marking
Standards and Guidelines
EMC CE-Emission of interference acc. to EN 61000-6-4: 2007
EMC CE-Immunity to interference acc. to EN 61000-6-2: 2005
More Information
Detailed references to the approvals are listed in the document "Overview
Approvals WAGO-I/O-SYSTEM 750", which you can find on the CD ROM
ELECTRONICC Tools and Docs (Item-No.: 0888-0412)
or in the internet under: http://www.wago.com Documentation 
WAGO-I/O-SYSTEM 750 System Description

750-631(750-631/000-001) [Incremental Encoder Interface] •17
Functional Description
WAGO-I/O-SYSTEM 750
I/O Modules
2.1.2.7 Functional Description
The incremental encoder interface is used to evaluate two 90° phase-shifted
track signals delivered by digital encoders. If required, the signals generated
by the index track can also be processed. Control via two 24 V signals is
optional.
Typically, incremental encoders provide two signals of the encoder track, both
90° offset. These signals are labeled A and B. To improve the common mode
rejection ratio, both signals are transmitted as differential signals. In addition
to the A signal, the complement signal /A is also transmitted. The difference
between the input signals is performed by the incremental encoder interface.
By exchanging A and /A the phase position will turn from A to B, thus
allowing the desired counting direction to be preset via the wiring
configuration.
Most incremental encoders have an index track in addition to the two track
signals. This index track generates a single pulse per encoder revolution. This
pulse can be used to determine the absolute encoder position within a
revolution. Through the appropriate initialization, the current counter value is
transmitted to a latch register using the index pulse. Since the index pulse has
the same duration as a track signal, the latch process should always be
performed in the same rotational direction.
The encoder is supplied with 5 V derived from the terminations Ue and U0.
This voltage is generated from an external 24 V power supply. The inputs 0 V
and U0 are connected internally.
The latch input controls the overtaking of the actual counter value into the
latch register. This input is activated by the control bit EN_LATEXT (”1“).
EN_LACT has to be deactivated (“0“). After activation, the first edge transi-
tion from 0 V to 24 V at the latch input takes the actual counter value into the
latch register. The control bit EN_LATEXT must be deleted and reset, so that
the counter value can be stored again.
The gate input stops the counter. Only 0 V or and open connection initialize
the counter. 24 V stops the counting process.
The latch and gate inputs are 24 V.

18 •750-631(750-631/000-001) [Incremental Encoder Interface]
Process Image
WAGO-I/O-SYSTEM 750
I/O Modules
Overview of Inputs and Outputs:
In-/Output Type Function
Signal A and Signal /A Input, TTL Incremental pulse signals for channel A
Signal B and Signal /B Input, TTL Incremental pulse signals for channel B
Signal C and Signal /C Input, TTL Track signal for the index channel of the sensor
Shield Input Shield connection for encoder wiring
Sensor 0 V Output, Vers. Ground for sensor signals and supply
Sensor +5 V Output, Vers. 5 V supply for encoder
+24 V Input, Vers. 24 V supply voltage for the sensor and data
processing
0 V Input, Vers. Ground for the 24 V supply voltage, internally
connected to sensor V0
Gate Input, 24 V 24 V input for gate signal
Latch Input, 24 V 24 V input for Latch signal
2.1.2.8 Process Image
Using the I/O module 750-631, a 6 byte input and output process image can be
transferred to the fieldbus coupler / controller via one logical channel. The
data sent and received is stored in 2 output bytes (D0, D1) and 4 input bytes
(D0, D1, D3, D4). The output bytes D2 ... D4 and the input byte D2 are
reserved and without function. One control byte (C0) and one status byte (S0)
are used to control the data flow.
Attention
The representation of the process data of some I/O modules or their variations
in the process image depends on the fieldbus coupler/-controller used. Please
take this information as well as the particular design of the respective
control/status bytes from the section "Fieldbus Specific Design of the Process
Data" included in the description concerning the process image of the
corresponding coupler/controller.
Input data Output data
S0 Status byte C0 Control byte
D0 Counter value byte 0 (LSB) D0 Setpoint value byte 0 (LSB)
D1 Counter value byte 1 (MSB D1 Setpoint value byte 1 (MSB)
D2 reserved D2 reserved
D3 Latched value byte 0 (LSB) D3 reserved
D4 Latched value byte 1 (MSB) D4 reserved

750-631(750-631/000-001) [Incremental Encoder Interface] •19
Process Image
WAGO-I/O-SYSTEM 750
I/O Modules
Control byte C0
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 0 0 0 0 CNT_
SET
EN_
LATEXT
EN_
LATC
EN_
LATC
The counter is set with a rising edge of CNT_SET to the value that is specified via the process
data.
EN_
LATEXT
The external latch input is activated. With the first external latch pulse after validity of the
EN_LATEXT bit, the counter value is stored in the latch register. The following pulses have no
influence on the latch register when the bit is set.
CNT_
SET
The zero point latch (C input) is activated. With the first external latch pulse after the validity of
the EN_LATC bit, the counter value is stored in the latch register (this has priority over
EN_LATEX). The following pulses have no influence on the latch register when the bit is set.
0 reserved
Status byte S0
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 0 0 OVER-
FLOW
UNDER-
FLOW
CNTSET
_ACK
LA-
TEXT_
VAL
LATC_
VAL
LATC_VAL A zero point latch has occurred. The data D3, D4 in the process image corresponds to the latched
counter value when the bit is set. To reactivate the latch input, EN_LATC must first be cancelled
and then the bit must be set again.
LATEXT_
VAL
An external latch pulse has occurred. The data D3, D4 in the process image corresponds to the
latched counter value when the bit is set. To reactivate the latch input, EN_LATEXT must first
be cancelled and then the bit must be set again.
CNTSET_
ACK
The data for setting the counter has been accepted from the module.
UNDER-
FLOW
This bit is set if an underflow (0 to 65535) of the 16-bit counter occurs. It is reset when the
counter drops below two thirds of the measurement range (43690 to 43689) or as soon as an
overflow occurs.
OVER-
FLOW
This bit is set if an overflow (65535 to 0) of the 16-bit counter occurs. It is reset if the counter
exceeds a third of the measurement range (21845 to 21846) or as soon as an underflow occurs.
0 reserved
The following tasks can be performed or checked via the control and status
byte:
Extending the counter above 16 bits:
The internal counter has a width of 16 bits. Should the application require an
extended range for the location values, the extended counter range may be
calculated within the control system using the location-difference-integration
method. This method uses the control system to store the last location value
(counter value). Any new location value will have the previously stored
counter value subtracted from it. Using the sign bit, this difference will be
completed with the desired number of extension bits and then be added to the
accumulated location value. It is assumed that the counter difference of the
two counter queries is smaller than (16-1) bits therefore counter overflows
need not be considered.

20 •750-631(750-631/000-001) [Incremental Encoder Interface]
Process Image
WAGO-I/O-SYSTEM 750
I/O Modules
Another method calculates the counter extension separately by adding the bit
OVERFLOW (status bit 4) or subtracting the bit UNDERFLOW (status bit 3)
once, each time the counter value is read. Between two counter queries, the
counter value should not be increased or decreased by more than 1/3 x
0xFFFF. Due to the separate calculation of the counter extension, this
procedure allows for calculation using smaller data widths.
Setting the counter value:
Presetting the counter value is possible via the CNT_SET bit (control bit 2).
The new counter value is transferred in the load value. When the CNT_SET
bit is set from “0“ to “1“, the counter is loaded with the load value. The
CNTSET_ACC bit (status bit 2) is set to ”1“ when the loading is completed
Maintaining the present counter value:
The present counter value may be maintained or latched via the external latch
input. To do so, the EN_LATEXT bit (control bit 1) is set in the control word.
Upon transition from ”0“ to ”1“, the latch value will contain the counter value
at the time of the edge transition. Upon completion of the latch process the
LATEXT_VAL bit (status bit 1) will be set to ”1“. Calculating the extended
latch value is done as shown above.
Maintaining a reference point:
The storage of a present counter value may also be accomplished via the index
pulse from the encoder. Releasing is done when the EN_LATC bit (control bit
0) is set to “1“. The storage of the counter value is completed when
LATC_VAL = 1 (status bit 0).