NORD BU0550 User Manual

NORDAC SK 200E Manual Safety information

GB

BU 0550

PLC logic

for NORD SK 54xE frequency inverters

BU 0550 GB-0813 1

PLC logic for NORD SK 54xE frequency inverters Safety information

N O R D Frequency inverters

Safety and operating instructions for

drive power converters

(as per: Low Voltage Directive 2006/95/EEC )

1. General
Depending on their protection class, drive power converters may

have live, bare, moving or rotating parts or hot surfaces during
operation.

Unauthorised removal of covers, improper use, incorrect installation
or operation causes a risk of serious personal injury or material
damage.

Further information can be found in this documentation.
All transportation, installation, initialisation and maintenance work

must be carried out by qualified personnel (compliant with IEC
364, CENELEC HD 384, DIN VDE 0100, IEC 664 or DIN VDE 0110,
and national accident prevention regulations).

For the purposes of these basic safety instructions, qualified
personnel are persons who are familiar with the assembly,
installation, commissioning and operation of this product and who
have the relevant qualifications for their work.

2. Proper use in Europe

Drive power converters are components intended for installation in
electrical systems or machines.

When installed in machines, the drive power converter cannot be
commissioned (i.e. commencement of the proper use) until it has
been ensured that the machine meets the provisions of the EC
Directive 2006/42/EEC (Machine Directive); EN 60204 must also be
complied with.

Commissioning (i.e. implementation of the proper use) is only
permitted if the EMC Directive (2004/108/EEC) is complied with.

Drive power converters with the CE mark meet the requirements of
the Low Voltage Directive 2006/95/EEC. The harmonized standards
stated in the Declaration of Conformity are used for the drive power
converters.

Technical data and information for connection conditions can be
found on the rating plate and in the documentation, and must be
complied with.

The drive power converters may only be used for the safety
functions which are described and for which they have been
explicitly approved.

3. Transport, storage

Information regarding transport, storage and correct handling must
be complied with.

4. Installation

The installation and cooling of the equipment must be implemented
according to the regulations in the corresponding documentation.

The drive power converters must be protected against
impermissible loads. Especially during transport and
handling, components must not be deformed and/or
insulation distances must not be changed. Touching of
electronic components and contacts must be avoided.

Drive power converters have electrostatically sensitive
components, which can be easily damaged by incorrect
handling. Electrical components must not be mechanically
damaged or destroyed (this may cause a health hazard!).

5. Electrical connections

When working on live drive power converters, the applicable
national accident prevention regulations must be complied
with (e.g. VBG A3, formerly VBG 4).

The electrical installation must be implemented according to
the applicable regulations (e.g. cable cross-section, fuses,
ground lead connections). Further information is contained
in the documentation.

Information about EMC-compliant installation – such as
shielding, earthing, location of filters and installation of
cables can be found in the drive power converter
documentation. These instructions must be complied with
even with CE marked drive power converters. Compliance
with the limiting values specified in the EMC regulations is
the responsibility of the manufacturer of the system or
machine.

6. Operation

Where necessary, systems where drive power converters
are installed must be equipped with additional monitoring
and protective equipment according to the applicable safety
requirements, e.g. legislation concerning technical
equipment, accident prevention regulations, etc.

The parameterisation and configuration of the drive power
converter must be selected so that no hazards can occur.

All covers must be kept closed during operation.

7. Maintenance and repairs

After the drive power converter is disconnected from the
power supply, live equipment components and power
connections should not be touched immediately, because of
possible charged capacitors. Observe the relevant
information signs located on the drive power converter.

Further information can be found in this documentation.

These safety instructions must be kept in a safe place!

2 BU 0550 GB-0813

NORDAC SK 200E Manual Safety information

BU 0550 GB-0813 3

PLC logic for NORD SK 54xE frequency inverters Concerning this document

Designation of
previous issues

Software
Version

Comments

BU 0550 GB, September 2011
Part No. 607 5501 / 3911

V 2.0 R0

First issue

BU 0550 GB, October 2011
Part No. 607 5501 / 4211

V 2.0 R1

Correction of errors / Change of function of the operators
ANDN / ORN / XORN

BU 0550 GB, February 2013
Part No. 607 5501 / 0813

V 2.1 R0

The following PLC modules have been added: MC_Control,
FB_Capture, FB_Read, FB_Write, FB_Weigh

For some MCs the BUSY output was updated.
The process values 35 to 36, 62 to 66 and 141 to 147 have

been added.
Functional extension in the section "jump marks"
Command "SQR" renamed as "SQRT"
The input RAMONLY is new in MC_WriteParameter16/32
The input MODE is new in MC_Home
Names for process values corrected
Number of PLC errors increased to 16
Addressing possibilities for PDO improved
Example program supplemented

NOTE

This supplementary operating manual is only valid in conjunction with the operating manual
supplied for the respective frequency inverter (Manual BU0500).

Documentation

Designation: BU 0550 GB
Part No.: 607 55 01
Device series: SK 540E, SK 545E

Version list

Publisher

Getriebebau NORD GmbH & Co. KG

Rudolf-Diesel-Str. 1  D-22941 Bargteheide  http://www.nord.com/
Tel.: [phone] / 289-0  Fax [phone]

4 BU 0550 GB-0813

PLC logic for NORD SK 54xE frequency inverters Concerning this document

Intended use of the frequency inverter

Compliance with the operating instructions is essential for fault-free operation and the

acceptance of any warranty claims. These operating instructions must be read before
working with the device!

These operating instructions contain important information about servicing. They must
therefore be kept close to the device.

NORD frequency inverters are devices for industrial an commercial systems used for the
operation of three-phase asynchronous motors with squirrel-cage rotors and Permanent
Magnet Synchronous Motors – PMSM (SK 54xE and above) These motors must be suitable
for operation with frequency inverters, other loads must not be connected to the devices.

SK 5xxE frequency inverters are devices for stationary installation in control cabinets. All
details regarding technical data and permissible conditions at the installation site must be
complied with.

Commissioning (commencement of the intended use) is not permitteduntil it has been ensured
that the machine complies with the EMC Directive 2004/108/EEC and that the conformity of
the end product meets the Machinery Directive 2006/42/EEC (observe EN 60204).

 Getriebebau NORD GmbH & Co. KG, 2013

BU 0550 GB-0813 5

PLC logic for NORD SK 54xE frequency inverters Concerning this document

6 BU 0550 GB-0813

Table of Contents

1 GENERAL INFORMATION ...................................................................................................... 9

1.1 Specification of the PLC ....................................................................................... 9

1.2 PLC structure ........................................................................................................ 9

1.2.1 Memory ..................................................................................................................... 9

1.2.2 Process image ........................................................................................................ 10

1.2.3 Program Task ......................................................................................................... 10

1.2.4 Setpoint processing................................................................................................. 11

1.2.5 Data processing via accumulator ............................................................................ 11

1.3 Scope of functions .............................................................................................. 12

1.3.1 Motion Control Lib ................................................................................................... 12

1.3.2 Electronic gear with Flying Saw .............................................................................. 12

1.3.3 Visualisation ............................................................................................................ 12

1.3.4 Process controller ................................................................................................... 13

1.3.5 CANopen communication ....................................................................................... 13

2 CREATION OF PLC PROGRAMS ......................................................................................... 14

2.1 Loading, saving and printing .............................................................................. 14

2.2 Editor .................................................................................................................. 14

2.2.1 Variables and FB declaration .................................................................................. 15

2.2.2 Input window ........................................................................................................... 15

2.2.3 Watch and Breakpoint display window .................................................................... 16

2.2.4 PLC message window............................................................................................. 16

2.3 Load PLC program into the FI ............................................................................ 16

2.4 Debugging .......................................................................................................... 17

2.4.1 Observation points (Watchpoints) ........................................................................... 17

2.4.2 Holding points (Breakpoints) ................................................................................... 17

2.4.3 Single Step ................................................................ ................................ .............. 17

2.5 PLC configuration ............................................................................................... 18

2.6 PLC program start .............................................................................................. 18

2.7 Program example ............................................................................................... 19

3 AWL (INSTRUCTION LIST, IL) .............................................................................................. 20

3.1 General ............................................................................................................... 20

3.1.1 Data types ............................................................................................................... 20

3.1.2 Literal ...................................................................................................................... 20

3.1.3 Comments ................................................................ ................................ ............... 21

3.1.4 Jump marks ............................................................................................................ 21

3.1.5 Function call-ups ..................................................................................................... 22

3.1.6 Bit-wise access to variables .................................................................................... 22

3.2 Operators ............................................................................................................ 22

3.2.1 Loading and storage operators ............................................................................... 22

3.2.2 Arithmetical operators ............................................................................................. 24

3.2.3 Extended mathematical operators .......................................................................... 29

3.2.4 Bit Operations ......................................................................................................... 31

3.2.5 Comparison operators............................................................................................. 37

3.3 Jumps ................................................................................................................. 40

3.3.1 JMP ......................................................................................................................... 40

3.3.2 JMPC ...................................................................................................................... 40

3.3.3 JMPCN .................................................................................................................... 40

3.4 Type conversion ................................................................................................. 41

3.4.1 BYTE_TO_BOOL .................................................................................................... 41

3.4.2 BOOL_TO_BYTE .................................................................................................... 41

3.4.3 INT_TO_BYTE ........................................................................................................ 41

3.4.4 BYTE_TO_INT ........................................................................................................ 42

3.4.5 DINT_TO_INT ......................................................................................................... 42

3.4.6 INT_TO_DINT ......................................................................................................... 42

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PLC logic for NORD SK 54xE frequency inverters

3.5 Function blocks .................................................................................................. 43

3.5.1 Standard ................................................................................................................. 43

3.5.2 Motion Control ........................................................................................................ 50

3.5.3 Electronic gear unit with "Flying Saw" ..................................................................... 60

3.5.4 FB_FunctionCurve .................................................................................................. 63

3.5.5 FB_PIDT1 ............................................................................................................... 64

3.5.6 Visualisation with ParameterBox ............................................................................ 66

3.5.7 CANopen ................................................................................................................ 69

3.5.8 Recording of rapid events (FB_Capture) ................................................................ 74

3.5.9 Access to memory areas of the frequency inverter ................................................. 75

3.5.10 Weighing function (FB_Weigh) ............................................................................. 77

4 FREQUENCY INVERTER DETAILS ..................................................................................... 78

4.1 Parameters ........................................................................................................ 78

4.1.1 Operating displays .................................................................................................. 78

4.1.2 Control / PLC parameters ....................................................................................... 78

4.1.3 Control terminals ................................................................................................ ..... 80

4.1.4 Extra functions ........................................................................................................ 83

4.1.5 Information parameters ........................................................................................... 85

4.2 Process values .................................................................................................. 87

4.2.1 Inputs and outputs .................................................................................................. 87

4.2.2 PLC setpoints and actual values............................................................................. 88

4.2.3 Bus setpoints and actual values ............................................................................. 89

4.2.4 ControlBox and ParameterBox ............................................................................... 90

4.2.5 Info parameters ....................................................................................................... 90

4.2.6 PLC error ................................................................................................................ 91

4.2.7 PLC parameter ....................................................................................................... 92

4.3 PLC Error messages ......................................................................................... 93

5 LISTS / INDEX ....................................................................................................................... 94

5.1 Abbreviations: .................................................................................................... 94

5.2 Figures ............................................................................................................... 95

5.3 Tables ................................................................................................................ 95

5.4 Keyword index ................................................................................................... 97

8 BU 0550 GB-0813

1 General information

NOTE

Programming and download into the frequency inverter is exclusively via the NORD software
NORDCON.

Function

Specification

Standard

Orientated to IEC61131-3

Language

Instruction List ( IL )

Task

A cyclic task, program call-up every 5 ms

Computer performance

Approximately 200 AWL commands per 1 ms

Program memory

4032 Byte for flags, functions and the PLC program

Max. possible number of
commands

approximately 1280 commands
Attention! This is an average value. Heavy use of flags, process data and

functions considerably reduces the possible number of lines, see the
"Resources" section

Freely accessible CAN
mailboxes

20

Total memory

4032 Byte

Program memory
Flag memory

Variables

Instances of

function commands

The NORD SK 54xE frequency inverter contains logic processing which is similar to the current IEC61131-3
standard for memory programmable control units (SPS / PLC). The reaction speed or computing power of
this PLC is suitable to undertake smaller tasks in the area of the inverter. Inverter inputs or information from
a connected field bus can be monitored, evaluated and further processed into appropriate setpoint values
for the frequency inverter. In combination with other NORD devices, visualisation of system statuses or the
input of special customer parameters is also possible. Therefore, within a limited range, there is a potential
for savings via the elimination of a previous external PC solution.

AWL is supported as the programming language. AWL is a machine-orientated, text-based programming
language whose scope and application is specified in IEC61131-3.

1.1 Specification of the PLC

1 General

Table 1PLC specification

1.2 PLC structure

1.2.1 Memory

The PLC memory is divided into the program memory and the flag memory. In addition to the variables,
instances of function blocks are saved in the area of the flag memory. In instance is a memory area in which
all internal input and output variables of function command are saved. Each function command declaration
requires a separate instance. The boundary between the program memory and the flag memory is
determined dynamically, depending on the size of the flag area.

Fig. 1 Memory structure

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PLC logic for NORD SK 54xE frequency inverters

NOTE

If the blocks MC_Power, MC_Reset, MC_MoveVelocity, MC_Move…, MC_Home or MC_Stop
are used, the process values "PLC_Control_Word" and "PLC_Set_Val1" to "PLC_Set_Val5"
must not be used. Otherwise the values in the list of variables would always overwrite the
changes to the function block.

Read in
process

PLC program
execution

Save process
values

Start of
cycle

End of
cycle

In the flag memory, two different classes of variables are stored in the variable section:
[VAR]

Memory variables for storage of auxiliary information and statuses. Variables of this type are initialised every
time the PLC starts. The memory content is retained during the cyclic sequence of the PLC.

[VAR_ACCESS]
These are used to read and describe process data (inputs, outputs, setpoints, etc.) of the frequency inverter.

These values are regenerated with every PLC cycle.

1.2.2 Process image

Several physical dimensions such as torque, speed, position, inputs, outputs etc. are available to the
inverter. These dimensions are divided into actual and setpoint values. They can be loaded into the process
image of the PLC and influenced by it. The required process values must be defined in the list of variables
under the class VAR_ACCESS.

With each PLC cycle, all of the process data for the inverter which is defined in the list of variables is newly
read in. At the end of each PLC cycle the writable process data is transferred back to the inverter. See the
following diagram.

Fig. 2 Process image

Because of this sequence it is important to program a cyclic program sequence. Programming loops in order
to wait for certain events (e.g. changes of input level) does not produce the required result.

This behaviour is different in the case of function blocks which access process values. Here, the process
value is read on call-up of the function block and the process values are written immediately when the block
is terminated.

1.2.3 Program Task

Execution of the program in the PLC is carried out as a single task. The task is called up cyclically every 5
ms and its maximum duration is 3 ms. If a longer program cannot be executed in this time, the program is
interrupted and continued in the next 5 ms task.

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1.2.4 Setpoint processing

CAN /CANopen

USS

TU3_xxx

Local

PLC

Cycle 5ms

P509 &
P510[1]

Cycle 1 ms

P350

P350=0

P350=1

P351

Setpoint

The inverter has a variety of setpoint sources, which are ultimately linked via several parameters to form a
frequency inverter setpoint.

1 General

Fig. 3 Generation of control word and main setpoints from a range of possible sources

If the PLC is activated (P350=1) preselection of setpoints from external sources (main setpoints) is carried
out via P509 and P510[-01] Via P351, a final decision is made as to which setpoints from the PLC or values
input via P509/P510[-01] are used. A mixture of both is also possible.

No changes to the auxiliary setpoints (P510[-02]) are associated with the PLC function. All auxiliary setpoint
sources and the PLC transfer their auxiliary setpoint to the frequency inverter with equal priority.

1.2.5 Data processing via accumulator

The accumulator forms the central computing unit of the PLC. Almost all AWL commands only function in
association with the accumulator. The NORD PLC has three accumulators. These are the 23 Bit Accumula­tor 1 and Accumulator 2 and the AE in BOOL format.

The AE is used for all boolean loading, storage and comparison operations. If a boolean value is loaded, it is
displayed in the AE. Comparison operations transfer their results to the AE and conditional jumps are
triggered by the AE.

Accumulator 1 and Accumulator 2 are used for all operands in the data format BYTE, INT and DINT.
Accumulator 1 is the main accumulator and Accumulator 2 is only used for auxiliary functions. All loading
and storage operands are handled by Accumulator 1. All arithmetic operands save their results in
Accumulator 1. With each Load command, the contents of Accumulator 1 are moved to Accumulator 2. A
subsequent operator can link the two accumulators together or evaluate them and save the result in
Accumulator 1, which in the following will generally be referred to as the "accumulator".

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PLC logic for NORD SK 54xE frequency inverters

1.3 Scope of functions

The PLC supports a wide range or operators, functions and standard function modules, which are defined in
IEC1131-3. A detailed description can be found in the following sections (Sections 2.7 and 4)

Function blocks which are additionally supported are also explained (see Section 3.5 ).

1.3.1 Motion Control Lib

The Motion Control Lib is orientated to the PLCopen specification "Function blocks for motion control". This
mainly contains function blocks which are used to move the drive. In addition, function blocks for reading
and writing FI parameters are also provided.

1.3.2 Electronic gear with Flying Saw

The inverter is equipped with the functions electronic gear (synchronous operation in positioning mode) and
Flying Saw. Via these functions the inverter can follow another drive unit with angular synchronism. Also, via
the additional Flying Saw function it is possible to synchronize to the precise position of a moving drive. The
electronic gear mode can be started and terminated at any time. This enables a combination of conventional

position control with its move commands and gear unit functions.
For the gear function a NORD frequency inverter with internal CAN bus is required on the master axis.

1.3.3 Visualisation

Visualisation of the operating status and the parameterisation of the frequency inverter is possible with the
aid of a ControlBox or a ParameterBox.

Alternatively, the CANopen Master functionality of the PLC CAN bus panel can be used to display
information.

1.3.3.1 ControlBox

The simplest version for visualisation is the ControlBox. The 4-digit display and the keyboard status can be
accessed via two process values. This enables simple HMI applications to be implemented very quickly.

In order for the PLC to access the display, P001 must be set to "PLC-Ctrlbox Value". A further special
feature is that the parameter menu is no longer accessed via the arrow keys. Instead, the "On" and "Enter"
keys must be pressed simultaneously.

1.3.3.2 ParameterBox

In visualisation mode, each of the 80 characters in the P-Box display (4 rows of 20 characters) can be set
via the PLC. It is possible to transfer both numbers and texts. In addition. keyboard entries on the P-Box can
be processed by the PLC. This enable the implementation of more complex HMI functions (display of actual
values, change of window, transfer or setpoints etc.). Access to the P-Box display is via function blocks in
the PLC.

Visualisation is via the operating value display of the ParameterBox. The content of the operating value
display is set via the P-Box parameter P1003. This parameter can be found under the main menu item
"Display". P1003 must be set to the value "PLC display". After this, the operating value display can be
selected again by means of the right and left arrow keys. The display controlled by the PLC is then shown.
This setting remains in effect even after a further switch-on.

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1.3.4 Process controller

The process controller is a PID-T1 controller with a limited output size. With the aid of this function module
in the PLC it is possible to simply set up complex control functions, by means of which various processes,
e.g. pressure regulation can be implemented in a considerably more elegant manner than with the
commonly used two-point controllers.

1.3.5 CANopen communication

In addition to the standard communication channels, the PLC provides further possibilities for
communication. Via the internal CAN bus of the inverter (connection via the RJ45 sockets), it can set up
additional communications with other devices. The protocol which is used for this is CANopen.
Communications are restricted to PDO data transfer and NMT commands. The standard CANopen inverter
communication via SDO, PDO1, PDO2 and Broadcast remains unaffected by this PLC function.

PDO (Process Data Objects)

Other frequency inverters can be controlled and monitored via PDO. However, it is also possible to connect
devices from other manufacturers to the PLC. These may be IO modules, CANopen encoders, or panels
etc. With this, the number of inputs and outputs of the frequency inverter can be extended at will. Analog
outputs would then also be possible.

NMT (Network Management Objects)

All CANopen devices must be set to the CANopen bus state "Operational" by the bus master. PDO
communication is only possible in this bus state. If there is no bus master in the CANopen bus, this must be
performed by the PLC. The function module FB_NMT is available for this purpose.

1 General

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PLC logic for NORD SK 54xE frequency inverters

Input window
Variables and FB

declaration

Watch and Breakpoint
display window

PLC message
window

2 Creation of PLC programs

Creation of PLC programs is carried out exclusively via the PC program NORDCON. The PLC editor is
opened either via the menu item "File/New/PLC program" or via the symbol . This button is only active if

a frequency inverter with PLC functionality forms the focus of the device overview.

2.1 Loading, saving and printing

The functions Load, Save and Print are carried out via the appropriate entries in the main menu or in the
symbol bars.

When opening, it is advisable to set the data type to "PLC Program" (*.awl / *.awlx) in the Windows dialog.
With this, only files which can be read by the PLC editor are displayed.

If the PLC program which is created is to be saved, the Windows window of the PLC editor must be active.
The PLC program is saved by actuating "Save" or "Save as". With the operation "Save as", this can also be
recognised by the data type (540E PLC (*.awlx)).

The appropriate PLC window must be active in order to print the PLC program. Printout is then started via
"File/Print" or the appropriate symbol.

2.2 Editor

The PLC Editor is divided into four different windows.

Fig. 4 PLC Editor

The individual windows are described in more detail in the following sections.

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2 Creation of PLC programs

2.2.1 Variables and FB declaration

All the variables, process values and function blocks which are required by the program are declared in this
window.

Fig. 5 Declaration window

Variables
Variables are set up by setting the class "VAR". The Name of the variable can be freely selected. In the
Type field, a selection can be made between BOOL, BYTE, INT and DINT. A start initialisation for the
variables can be entered under Init-. Value.

Process values
These can be set up by selecting the entry "VAR_ACCESS" under Class. The Name cannot be freely
selected and the field Init. Value is barred for this type.

Function modules
The entry "VAR" is selected under Class. The Name for the relevant instance of the function module (FB)
can be freely selected. The required is selected under Type. An Init. Value cannot be set for the FB.

All menu items which concern the variable window can be called up via the context menu (right mouse
button). Via this, entries can be added and deleted. Variables and process variables for monitoring
(Watchdog function) or debugging (Breakpoint) can be activated.

2.2.2 Input window

The input window is used to enter the program and to display the AWL program. It is provided with the
following functions:

 Syntax highlighting
 Bookmarks
 Declaration of variables
 Debugging

Syntax highlighting
If the command and the assigned variable are recognised by the Editor, the command is displayed in blue
and the variable in black. As long as this is not the case, the display in in thin black italics.

Bookmarks
As programs in the Editor can have a considerable length, it is possible to mark and jump to important
points in the program via the Bookmarks function. The cursor must be located in the relevant line in order to
mark it. Via the menu item "Switch bookmark" (right mouse button menu) the line is marked with the
required bookmark. The bookmark is accessed via the menu item "Go to bookmark".

Declaration of variables
New variables can be declared via the Editor by means of the editor menu "Add variable" (right mouse
button).

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PLC logic for NORD SK 54xE frequency inverters

Debugging
The positions of the Break and Watchpoints for the Debugging function are specified in the Editor. This can
be done via the menu items "Switch breakpoint" (Breakpoints) and "Switch monitoring point" (Watchpoints).
The position of Breakpoints can also be specified by clicking on the left border of the Editor window.

Variables and process values which are to be read out from the frequency inverter during debugging must
be marked. This can be done in the Editor via the menu items "Debug variable" and "Watch variable". For
this, the relevant variable must be marked before the required menu item is selected.

2.2.3 Watch and Breakpoint display window

This window has two tabs, which are explained below.
Holding points

This window displays all the breakpoints and watchpoints which have been set. These can be switched on
and off via the checkboxes and deleted with the "Delete key". A corresponding menu can be called up with
the right mouse button.

Observation list
This displays all the variables which have been selected for observation. Their actual value is displayed in
the Value column. The display format can be selected via the Display column.

2.2.4 PLC message window

All PLC status and error messages are entered in this window. In case of a correctly translated program the
message "Translated without error" is displayed. The use of resources is shown on the line below this. In
case of errors in the PLC program, the message "Error X" is displayed. The number of errors is shown in X.
The following lines show the specific error message in the format:

[ Line number]: Error description

2.3 Load PLC program into the FI

In order for a program to be loaded into the FI the PLC window must be online and the program translated
without errors.

The PLC window is online if the PLC window is shown in the tree diagram of the FI (54xE). See following
picture.

Fig. 6 NORDCON overview window

This is achieved if the PLC window is opened via the PLC symbol .
If a PLC program is opened in the offline window, a device can be assigned to the PLC program via the

menu item "PLC -> Link". The PLC program can be reset to offline mode with the menu item "PLC ->
Detach".

The PLC program is loaded into the FI via the symbol and is saved immediately. After this, the
program can be started in the frequency inverter via the symbol.

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2 Creation of PLC programs

2.4 Debugging

As programs only rarely function the very first time, the NORD PLC provides several possibilities for finding
faults. These possibilities can be roughly divided into two categories, which are described in detail below.

2.4.1 Observation points (Watchpoints)

The simplest debugging variant is the Watchpoint function. This provides a rapid overview of the behaviour
of several variables. For this, an observation point is set at an arbitrary point in the program. When the PLC
executes this program line, up to 5 values are saved and displayed in the observation list ("Holding point"
window). The 5 values to be observed can be selected via the context menu (right mouse button) in the
input window or the variable window.

2.4.2 Holding points (Breakpoints)

Via holding points it is possible to deliberately stop the PLC program at a specific line of the program. If the
PLC runs into a holding point, the AE, Accumulator 1 and Accumulator 2 are read out, together with all the
variables which have been selected under the menu item "Debug variables" (right mouse menu).

Up to 5 Breakpoints can be set in a PLC program.
This function is started via the symbol. The program now runs until a holding point is triggered. Further

actuation of the symbol bar allows the program to continue running until it reaches the next holding point.

If the program is to continue running, the symbol is actuated.

2.4.3 Single Step

With this debugging method it is possible to execute the PLC program line for line. With each individual
step, all the selected variables are read out of the FI PLC and displayed in the "Observation list" window.
The values to be observed can be selected in the input window or the variable window by means of the right
mouse button menu.

The prerequisite for debugging in single steps is that at least one holding point (see Section 2.4.2) has been
set before debugging is started. The debugging mode is switched on by actuating the symbol. It is only
possible to debug the program in single steps via the symbol after the program has run into the first

holding point.
Some command lines contain several individual commands. Because of this it is possible that two or more

individual steps must be executed before the step indicator moves forward in the input window. The actual
position is shown by a small arrow in the left PLC Editor window.

When the symbol is actuated, the program continues running until the next holding point.

If the program is to continue running, the symbol is actuated.

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PLC logic for NORD SK 54xE frequency inverters

2.5 PLC configuration

The PLC configuration dialogue is opened via the symbol. Here, basic settings for the PLC can be
made, which are described in further detail below.

Cycle time monitoring

This function monitors the maximum processing time for a PLC cycle. With this, unintended continuous
program loops in the PLC program can be caught. The time can be set in 5ms steps up to a maximum of 1
second. Error 22.4 is triggered in the frequency inverter if this time is exceeded.

Allow ParameterBox function module

This option must be activated (see Section 3.5.6) if visualisation via the ParameterBox is to be carried out in
the PLC program. Otherwise, the relevant function blocks generate a Compiler error when the frequency
inverter is started.

Invalid control data

The PLC can evaluate control words which are received from the possible bus systems. However, the
control words can only get through if the bit "PZD valid" (Bit 10) is set. This option must be activated if
control words which are not compliant with the USS protocol are to be evaluated by the PLC. Bit 10 in the
first word is then no longer queried.

Warm start after error

When the PLC starts, all variables are always loaded with "0" or their initialisation value. It does not matter
whether the start is performed after a stop, a program download or a PLC error.

With the option "Warm start after error the content of the variables is not changed for a warm start. A warm
start is performed after a PLC Stop command or a PLC error.

Do not pause the system time at holding point

The system time is paused during debugging if the PLC is in the holding point or in single step mode. The
system time forms the basis for all timers in the PLC.

This function must be activated if the system time is to continue running during debugging.

2.6 PLC program start

Execution of a PLC program in the frequency inverter can be started in several ways:

 NORDCON: Activation of the symbol in the menu bar.
 Parameter P350 setting 1 "On" - The program starts immediately after the control board of the

frequency inverter becomes ready for operation - e.g after the power supply is switched on.

 In case of interruptions of the program by P420/P480 [-xx] setting 80 "PLC Stop": by resetting the

input.

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3 AWL (Instruction List, IL)

Parameter P350 = 1

Control of the FI via PLC

Parameter P351 = 0

Control work and main setpoint from the PLC

Parameter P553[-01] = 1

The PLC setpoint 1 is defined as the setpoint frequency

_5_State_digital_input

Status of the digital inputs

_7_Analog_input1

Value of analog input 1

_21_PLC_set_val1

PLC – setpoint 1

Run

Instance of the Motion Control module "MC_Power" (name freely selectable)

Command

Meaning

Example

LD _5_State_digital_input.0

Reads the status of the digital inputs and loads the

value of digital input 1 into the accumulator

Digital input 1: high  Accumula­tor = 1

ST Run.Enable

Saves the value from the accumulator in the Mo-

tion Control block called up by the variable Run as
the value for Enable.

Enable = 1

LD _7_Analog_input1

Reads the value of analog input 1 (Standardisation:

10 V = 1000) and loads it into the accumulator

AIn1 = 2.5 V  accumulator = 250

SUB int#500

Subtracts the integer value 500 from the accumu-

lator (shifts the 0-point from 0 to 5 V)

250 - 500 = Accumulator = - 250

MUL int#32

Multiplies the integer value 32 with the accumula-

tor value ( Standardisation of the setpoint to the
value range of the FI (100 % = 4000

hex

≈

16000

dec

).

-250 * 32 = Accumulator = - 8000

dec

ST _21_PLC_set_val1

Saves the accumulator in the process variable

PLC-setpoint1.

-8000

dec

 setpoint - 50 %

(Setpoint 50 % of the maximum
frequency in the direction of rota­tion to the left)

Cal Run

The Motion Control function module for setting the

output stage of the inverter is executed

Output stage is enabled.

2.7 Program example

1. Comment to program function and the outline conditions for the program
e.g parameterise inverter for PLC control (the parameterisation must be carried out in the inverter.):

2. Definition of the variables and process values used in the PLC

3. Program sequence

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PLC logic for NORD SK 54xE frequency inverters

Name

Required memory space

Value range

BOOL

1 bit

0 to 1

BYTE

1 Byte

0 to 255

INT

2 Byte

-32768 to 32767

DINT

4 Byte

-2,147,483,648 to 2,147,483,647

LABEL_ADDRESS

2 Byte

Jump marks

Literal

Example

Number displayed in decimal

BOOL

FALSE

0

TRUE

1

BOOL#0

0

BOOL#1

1

Dual (Base 2)

2#01011111

95

2#0011_0011

51

BYTE#2#00001111

15

BYTE#2#0001_1111

31

Octal (Base 8)

8#0571

377

8#05_71

377

BYTE#8#10

8

BYTE#8#111

73

BYTE#8#1_11

73

Hexadecimal (Base 16)

16#FFFF

-1

16#0001_FFFF

131071

INT#16#1000

4096

DINT#16#0010_2030

1056816

Integer (Base 10)

10

10

-10

-10

10_000

10000

INT#12

12

DINT#-100000

-100000

Time

TIME#10s50ms

10.050 seconds

T#5s500ms

5.5 seconds

TIME#5.2s

5.2 seconds

TIME#5D10H15M

5 days + 10 hours + 15 minutes

T#1D2H30M20S

1 day + 2 hours + 30 minutes + 20 seconds

3 AWL (Instruction List, IL)

3.1 General

3.1.1 Data types

The PLC supports the data types listed below.

Table 2 Data types

3.1.2 Literal

For greater clarity it is possible to enter constants for all data types in various display formats. The following
table gives an overview of all possible variants.

Table 3 Numeric literals

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3.1.3 Comments

It is advisable to provide the sections of the program with comments in order to make the PLC program
understandable at a later date. In the application program these comments are marked by starting with the
character sequence "(*" and finishing with "*)" as shown in the following examples. These comments are not
communicated to the frequency inverter.

(* Comment about a program block *)

LD 100 (* Comment about a command *)
ADD 20

3.1.4 Jump marks

Entire sections of the program can be skipped with the aid of the operators JMP, JMPC or JMPCN (see
Section 3.3). A jump mark is given as the target address. With the exception of umlaut characters and "ß"
they may contain all letters, the numbers 0 to 9 and underscores. Other characters are not permitted. The
jump mark is terminated with a colon. This may stand on its own. There may also be further commands after
in the same line after the jump mark.

Possible variants may appear as follows

Jump mark:
LD 20

This_is_a_jump_mark:
ADD 10

MainLoop: LD 1000

A further variant is the transfer of a jump mark as a variable. This variable must be defined as type
LABLE_ADDRESS in the variable table, then this can be loaded into the variable 'jump marks'. With this, a
status machine can be created very simply, see below

JMP Address_Var

Address_1:

LD Address_2
ST Address_Var
JMP End

Address_2:

LD Address_3
ST Address_Var
JMP End

Address_3:

LD Address_1
ST Address_Var

End:

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PLC logic for NORD SK 54xE frequency inverters

Command

Meaning

LD Var1.0

Loads Bit 0 of Var1 into the AE

ST Var1.7

Stores the AE on Bit 7 of Var1

EQ Var1.4

Compares the AE with Bit 4 of Var1

Operator

Explanation

LD

Load

LDN

Load negated (BOOL)

ST

Memory

STN

Memory negated (BOOL)

3.1.5 Function call-ups

At present, the Editor only supports the following list form for function call-ups. The function CTD is called up
via the instance I_CTD. The results are saved in variables. The meaning of the functions used below is
described in further detail later in the manual.

 LD 10000
 ST I_CTD.PV
 LD LoadNewVar
 ST I_CTD.LD
 LD TRUE
 ST I_CTD.CD
 CAL I_CTD
 LD I_CTD.Q
 ST ResultVar
 LD I_CTD.CV
 ST CurrentCountVar

3.1.6 Bit-wise access to variables

A simplified form is possible for access to a bit from a variable or a process variable.

Table 4 Bit-wise access to variables

3.2 Operators

3.2.1 Loading and storage operators

Table 5 Overview of loading and storage operations

22 BU 0550 GB-0813

BOOL

BYTE

INT

DINT

Possible data types

X X X

X

Commands

Explanation

LD 10

Loads 10 as BYTE

LD -1000

Loads -1000 as BYTE

LD Value1

Loads variable Value 1

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LDN Value1

Value1 = TRUE  AE = FALSE

ST Value2

Save to Value2 = FALSE

BOOL

BYTE

INT

DINT

Possible data types

X X X

X

Commands

Explanation

LD 100

Loads the value 100

ST Value2

Accumulator content 100 is saved in Value1

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LD Value1

Value1 = TRUE  AE = TRUE

STN Value2

Save to Value2 = FALSE

3.2.1.1 LD

Loads a constant or a variable into the AE or into the accumulator

Table 6 LD

3.2.1.2 LDN

Loads the negative value of a boolean variable into the AE

3 AWL (Instruction List, IL)

Table 7 LDN

3.2.1.3 ST

Saves the content of the AE or accumulator to a variable. The variable to be saved must match the
previously loaded and processed data type.

Table 8 ST

3.2.1.4 STN

Saves the content of the AE to a variable and negates it. The variable to be saved must match the
previously loaded and processed data type.

Table 9 STN

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PLC logic for NORD SK 54xE frequency inverters

Operator

Explanation

ABS

Absolute value

ADD

Addition

DIV

Division

LIMIT

Limiter

MAX

Determines the larger of two numbers

MIN

Determines the lesser of two numbers

MUX

Multiplexer

MOD

Modulus operation

MUL

Multiplication

SUB

Subtraction

NOTE

Some of the following operators may also contain further commands. These must be placed in
brackets behind the operator

It must be noted that a space must be included behind the opened bracket. The closing bracket
must be placed on a separate line of the program.

LD Var1
ADD( Var2

SUB Var3
)

BOOL

BYTE

INT

DINT

Possible data types

X

X

Commands

Explanation

LD -10

Loads the value -10

ABS

Accu = 10

ST Value2

Saves the value 10 in Value1

3.2.2 Arithmetical operators

Table 10 Overview of arithmetical operators

3.2.2.1 ABS

Forms the absolute value from the Accumulator.

Table 11 ABS

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BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 10

ADD 204

Addition of two constants

LD 170

Addition of a constant and 2 variables.

ADD Var1, Var2

170

dec

+ Var1 + Var2

LD Var1

ADD( Var2

SUB Var3

Var1 + ( Var2 - Var3 )

)

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 10

DIV 2

Division of two constants

LD 170

Division of a constant and 2 variables.

DIV Var1, Var2

(170

dec

: Var1) : Var2

LD Var1

Divide Var1 by the contents of the brackets

DIV( Var2

Var1 : ( Var2 - Var3 )

SUB Var3

)

3.2.2.2 ADD and ADD(

Adds the variables and constants together with the correct prefixes. The first value for addition is in the
AE/accumulator, the second is loaded with the ADD command or is inside the bracket. Several variables or
constants can be added to the ADD command.

For bracket addition, the accumulator is added to the result of the expression in brackets. Up to 6 bracket
levels are possible.

The values to be added must belong to the same type of variable.

Table 12 ADD and ADD(

3.2.2.3 DIV and DIV(

Divides the accumulator by the operands. For divisions by zero, the maximum possible result is entered into
the accumulator, e.g. for a division with INT values, this is the value 0x7FFF or the value 0x8000 if the
divisor is negative.

For bracket division, the accumulator is divided by the result of the expression in brackets. Up to 6 bracket
levels are possible.

The values to be divided must belong to the same type of variable.
the part of the result following the decimal point are cut off. If places after the decimal point are required, the

remainder from the division can be determined with the Modulus operation (MOD) and further calculation
can be performed with this.

Table 13 DIV and DIV(

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PLC logic for NORD SK 54xE frequency inverters

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 10

Loads the value 10 into the accumulator

LIMIT 20,30

The value is compared with the limits 20 and 30. The value
in the accumulator is smaller, the accumulator is overwritten
with 20

ST Value1

Saves the value 20 in Value1

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 100

Load 100 into the accumulator

MAX 200

Compare with the value 200

ST Value2

Save the value 200 in Value2 (because it is the larger
value)

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 100

Load 100 into the accumulator

MIN 200

Compare with the value 200

ST Value2

Save the value 100 in Value2 (because it is the smaller
value)

3.2.2.4 LIMIT

This command limits the value in the accumulator to transferred minimum and maximum values. If this is
exceeded the maximum value in the accumulator is transferred and the minimum value is transferred if this
is undershot. There is no effect if the value is within the limits.

Table 14 LIMIT

3.2.2.5 MAX

This command determines the maximum value of two variables or constants. For this, the current value of
the accumulator is compared with the value transferred in the MAX command. After the command, the
larger of the two values is in the accumulator.

Both values must belong to the same type of variable.

Table 15 MAX

3.2.2.6 MIN

This command determines the minimum value of two variables or constants. For this, the current value of
the accumulator is compared with the value transferred in the MIN command. After the command, the
smaller of the two values is in the accumulator.

Both values must belong to the same type of variable.

Table 16 MIN

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3 AWL (Instruction List, IL)

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 1

Select the required element

MUX 10,20,30,40,Value1

MUX command with 4 constants and one variable

ST Value2

Save the value 20 in Value2

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 25

Load the dividends

MOD 20

Division 25/20  Modulus = 5

ST Var1

Save the result 5 in Var1

LD 25

Load the dividends

MOD( Var1

Result = 25/(Var1 + 10)  Modulus in the accumulator

ADD 10

)

ST Var3

Save the result 10 in Var3

3.2.2.7 MUX

Various constants or variables can be selected by means of an index which is located in front of the
command in the accumulator. The first value is accessed via Index 0. The selected value is loaded into the
accumulator. The number of values is only limited by the program memory.

Table 17 MUX

3.2.2.8 MOD and MOD(

The accumulator is divided by one or more variables or constants. The remainder from the division stands in
the accumulator as the result.

For bracket Modulus, the accumulator is divided by the result of the expression in the brackets and the
modulus is formed from this. Up to 6 bracket levels are possible.

Table 18 MOD and MOD(

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PLC logic for NORD SK 54xE frequency inverters

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 25

Load the multiplier

MUL Var1, Var2

25 * Var1 * Var2

ST Var2

Save the result

LD 25

Load the multiplier

MUL( Var1

Result = 25*(Var1 + Var2)

ADD Var2

)

ST Var3

Save the result as Var3

BOOL

BYTE

INT

DINT

Possible data types

X X

X

Commands

Explanation

LD 10

SUB Value1

Result = 10 - Value1

ST Value1
LD 20

SUB Value1,Value2,30

Result = 20 - Value1 - Value2 - 30

ST Value1

LD 20

SUB( 6

Subtract 20 from the contents of the bracket

AND 2

)

Result = 20 - (6 AND 2)

ST Value1

Save the result 18 in Var1

3.2.2.9 MUL and MUL(

Multiplication of the accumulator with one or more variables or constants.
For bracket multiplication, the accumulator is multiplied by the result of the expression in brackets. Up to 6

bracket levels are possible.
Both values must belong to the same type of variable.

Table 19 MUL and MUL(

3.2.2.10 SUB and SUB(

Subtracts the accumulator from one or more variables or constants.
For bracket subtraction, the accumulator is subtracted from the result of the expression in brackets. Up to 6

bracket levels are possible.
The values to be subtracted must belong to the same type of variable.

Table 20 SUB and SUB(

28 BU 0550 GB-0813

Operator

Explanation

EXP

Exponential function

LOG

Logarithm, base 10

LN

Logarithm, base e

SQRT

Root

COS, ACOS

Trigonometrical operators
SIN, ASIN

TAN, ATAN

NOTE

The operators listed here require a large amount of computation. This may result in a
considerably longer running time for the PLC program.

1000

1000

















Akku

eAkku

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LD 1000

EXP

Result = 2718

ST Var1

1000

1000

10

log 















Akku

Akku

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LD 1234

LOG

Result = 91

ST Var1

3.2.3 Extended mathematical operators

Table 21 Overview of extended mathematical operators

3 AWL (Instruction List, IL)

3.2.3.1 EXP

Forms the exponential of the accumulator to the base of Euler's number (2.718). Up to 3 places behind the
decimal point may be stated, i.e. 1.002 must be entered as 1002.

Table 22 EXP

3.2.3.2 LOG

Forms the logarithm to base 10 from the accumulator. Up to 3 places after the decimal point may be stated,
i.e. 1.000 must be entered as1000.

Table 23 LOG

BU 0550 GB-0813 29

PLC logic for NORD SK 54xE frequency inverters

1000

1000

ln 















Akku

Akku

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LD 1234

LN

Result = 210

ST Var1

Save the value 210 in Value1

1000

1000

















Akku

Akku

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LD 1234

SQRT

Result = 1110

ST Var1

Save the value 1110 in Var1

1000

1000

sin 















Akku

Akku

1000

1000

cos 















Akku

Akku

1000

1000

tan 















Akku

Akku

1000

1000

sin 















Akku

aAkku

1000

1000

cos 















Akku

aAkku

1000

1000

tan 















Akku

aAkku

BOOL

BYTE

INT

DINT

Possible data types

X

Commands

Explanation

LD 1234

SIN ST Var1

Save the value 943 in Var1

3.2.3.3 LN

Logarithm to base e (2.718). Up to 3 places behind the decimal point may be stated, i.e. 1.000 must be
entered as 1000.

Table 24 LN

3.2.3.4 SQRT

Forms the square root of the accumulator. Up to 3 places behind the decimal point may be stated, i.e. 1.000
must be entered as 1000.

Table 25 SQR

3.2.3.5 COS, ACOS, SIN, ASIN, TAN, ATAN

Calculates the relevant mathematical function. The value to be calculated must be available in the
accumulator in radians. The scaling corresponds to 1 = 1000.

Conversion: Angle in radians = (Angle in degrees * PI / 180)*1000
e.g. an angle of 90° is converted as follows  90° * 3.14 / 180) *1000 = 1571

Table 26 Trigonometrical functions

30 BU 0550 GB-0813