Festo SEC-ST-48-6-P01 Operating and installation instructions

Description
8046712
en 1507d
[8046714]
Motor controller
SEC-ST-48-6-P01

Designation SEC-ST-48-6-P01-EN.....................
Edition en 1507d..................................
Original de.......................................
Part no. [8046714].................................
EFesto AG & Co.KG, D‐73726 Esslingen,
Federal Republic of Germany
Internet: http://www.festo.com
E-Mail: [e-mail]
The reproduction, distribution and utilization of this docu
ment as well as the communicaton of its contents to others
without express authorization is prohibited. Offenders will be
held liable for the payment of damages. All rights reserved in
the event of the grant of a patent, utility module or design.

Contents and general instructions
III
Festo SEC-ST-48-6-P01-EN en 1507d English
Contents
Designated use VI........................................................
Target group VII..........................................................
Service VII...............................................................
Notes on the use of this manual VII...........................................
General information on stepping motor systems VIII.............................
Procedure for correctly adjusting the stepping motor XIII.........................
Important user instructions XVI..............................................
Trademarks XVIII...........................................................
Safety instructions XVIII.....................................................
1. System summary 1-1...............................................
1.1 Overview 1-3......................................................
1.2 Performance characteristics 1-3......................................
1.3 Controller part 1-4.................................................
1.3.1 Brief description 1-4........................................
1.4 Final output stage 1-4..............................................
1.4.1 Brief description 1-4........................................
1.4.2 Internal monitoring 1-4......................................
1.5 Displays 1-5......................................................
1.5.1 Ready-to-operate display 1-5.................................
1.5.2 Fault display 1-5............................................
1.6 User interfaces 1-6.................................................
1.6.1 Enable input 1-6............................................
1.6.2 Direction input 1-7..........................................
1.6.3 Clock input 1-8.............................................
1.6.4 Fault output 1-9............................................
1.7 Settings 1-10.......................................................
1.7.1 The step mode 1-10..........................................
1.7.2 The current setting 1-12......................................
1.7.3 The current reduction I-red 1-13................................
1.7.4 Enable switch 1-13...........................................
1.7.5 The buttons 1-14............................................

Contents and general instructions
IV Festo SEC-ST-48-6-P01-EN en 1507d English
2. Fitting 2-1........................................................
2.1 Dimensions 2-3....................................................
2.2 Current supply 2-5.................................................
2.3 Electromechanics: front view 2-6......................................
3. Installation 3-1...................................................
3.1 Material 3-3.......................................................
3.1.1 Manufacturer 3-3...........................................
3.1.2 Plug X1 for control cable 3-4..................................
3.1.3 Plug X2 for stepper motor connection 3-4.......................
3.1.4 Plug X3 for power supply 3-4.................................
3.1.5 PE connection of the SEC-ST 3-4...............................
3.2 Plug connectors and their pin assignments 3-5..........................
3.2.1 X1 plug for control cable KSPC-SECST-1.5 3-5...................
3.2.2 Motor cable and current supply for the SEC-ST 3-6................
3.3 Connecting the cables 3-7...........................................
3.3.1 Overview of connections 3-8..................................
3.3.2 SEC-ST complete system 3-9..................................
3.3.3 Connecting the motor to the SEC-ST 3-9........................
3.3.4 Connecting the SEC-ST to the power supply 3-10..................
3.3.5 Connecting the SEC-ST to the controller 3-10.....................
3.4 PE protective conductor and screening connections 3-11...................
3.4.1 Connection instructions 3-11..................................
3.4.2 Electrical isolation 3-11.......................................
3.5 Measures for complying with EMC guidelines 3-12........................
4. Commissioning 4-1................................................
4.1 Commissioning the SEC-ST 4-3.......................................
5. Diagnosis and error treatment 5-1....................................
5.1 Fault messages of the SEC-ST 5-3.....................................
5.2 Fault functions of the SEC-ST 5-4......................................

Contents and general instructions
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Festo SEC-ST-48-6-P01-EN en 1507d English
A. Technical appendix A-1.............................................
A.1 Technical specifications A-3..........................................
A.1.1 SEC-ST-48-6-P01 A-3........................................
A.1.2 Maximum ratings A-4........................................

Contents and general instructions
VI Festo SEC-ST-48-6-P01-EN en 1507d English
Designated use
The SEC-ST-48-6-P01, referred to here as the SEC-ST, Smart
Electromotor Controller Stepper motor, has been designed for
use in control cabinets for controlling stepper motors in
2-string technology.
The SEC-ST must be operated in a safe working environment.
An EMERGENCY STOP circuit must be installed for the sys
tem.
Operate the SEC-ST only under the permitted ambient condi
tions.
The SEC-ST may only be operated in a stationary industrial or
commercial system. The electromagnetic resistance to inter
ference of the power electronics is not designed for operation
in mobile systems, in households or in firms which are con
nected directly to the low voltage network.
Install the SEC-ST screened and earthed in a control cabinet.
Otherwise, the electromagnetic compatibility (EMC) of the
power electronics cannot be guaranteed.
The SEC-ST may only be used as follows:
– in accordance with designated use
– in its original state
– without any modifications by the user
– in faultless technical condition.
If additional commercially-available components such as sen
sors and actuators are connected, the specifiedlimits for pres
sures, temperatures, electrical data, torques, etc. must not
be exceeded.
Please observe the standards specified in the relevant
chapters and comply with technical regulations, as well as
with national and local regulations.

Contents and general instructions
VII
Festo SEC-ST-48-6-P01-EN en 1507d English
Target group
This manual is directed exclusively at technicians trained in
control and automation technology,
who are dealing for the first time with stepper motor con
trollers
or who already have experience of stepper motors.
Service
Please consult your local Festo service centre if you have any
technical problems.
Notes on the use of this manual
This manual will help you in successfully commissioning your
SEC-ST for the first time.
This manual contains important information and provides you
with the basic knowledge which you will require for operating
the SEC-ST correctly.
Most work steps in this manual are divided into two parts:
the description:
Here you can learn important instructions and the aim of
each work step.
the instructions:
Here you learn how to carry out the work steps.

Contents and general instructions
VIII Festo SEC-ST-48-6-P01-EN en 1507d English
General information on stepping motor systems
Description
Stepping motors are a special type of synchronous motor
triggered through electrical pulses from a required control
unit. Here, a pulse always corresponds to the same rotational
angle. This permits positioning without acknowledgement.
Due to their ”digital” rotation, stepping motors are used as
switch mechanisms and in positioning technology. It should
be noted that the control system does not receive any kind of
acknowledgement that the motor has, in fact, performed its
step.
Accuracy and resolution
The step angle depends on the structural form; for the two-
phase Festo stepping motors type MTR-ST, the angle is 1.8°
(+/-5%) in full step. A single step takes place when the two
coils receive full alternating current. Here, the stepping motor
performs a step of 1.8° each time the current to the coils al
ternates.
But it is also possible to supply the two coils simultaneously
with different current shares. The result is a 1/2, 1/4, 1/5,
1/8, 1/10 or 1/32 of a step, depending on the current share.
This allows considerable refinement in the maximum resolu
tion of positions to which a stepping motor can run.
The smallest incremental path (resolution) on a positioning
axis is determined by the motor’s step angle (number of steps
per revolution) and the feed constant of the positioning axis
(determined by the diameter of the input pinion or the slope
of the spindle).
This can be calculated as follows:

Contents and general instructions
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Festo SEC-ST-48-6-P01-EN en 1507d English
Number of steps per revolution +360°
Motor step .angle
Resolution +Feed constant of the axis @Gear multiplication
StepsńRevolution
Example
Motor step angle: 0.9° (+/- 5%) at half-
step
Feed constant of the positioning axis:120mm/revolution
Gear multiplication: 1/4 ( gear reduction i =
4 )
The above example results in a resolution of 0.075 mm per
step.
All positions that this motor-gear-axis combination can run to
are divisible by 0.075.
In contrast, if the motor runs in quarter step, the resolution is
0.0375 mm; in one-tenth step, even a resolution of 0.00375
mm per step would be possible. Axis play, circumferential
backlash of any gears and the tolerance of the stepping mo
tor itself have to be calculated in. The stepping motor’s toler
ance must always be taken into account as the absolute value
of the full step.
This must be considered when very precise positioning as
signments are to be executed.

Contents and general instructions
XFesto SEC-ST-48-6-P01-EN en 1507d English
Basic information
Despite the simplicity of the stepping motors, it should be
mentioned that it is not a controller. The control system does
not receive any kind of acknowledgement whether the motor
has, in fact, performed its step.
And so it is extremely important to dimension the motor using
its speed-torque characteristic curve. This ensures that the
applied load can, in fact, be moved by the motor with the
specified acceleration and speed.
If the motor loses a step, that is, if the applied load is greater
than the force the motor can produce, the part to be posi
tioned is no longer in the desired position. Errors that must
be monitored in the overall system, such as through limit
switches, can thus occur.
Start-stop frequency
Another important variable in the use of stepping motors is
the so-called start-stop frequency. It is the frequency or
speed at which the stepping motor can safely, that is, without
loss of step, start and also stop again under the torque to be
provided.
Losses of step can occur when decelerating (stopping) just as
much as when accelerating!

Contents and general instructions
XI
Festo SEC-ST-48-6-P01-EN en 1507d English
Resonance frequencies
Impressing of a fixed current for the maximum holding torque
of a stepping motor can cause the motor to tend to oscillate.
Since the stepping motor is a synchronous motor, it follows
the set field within very narrow limits. If no load is applied,
the rotor oscillates beyond the targeted step due to the very
low inertia. If excitation of the next step takes place at an
unfavourable time, the system resonates.
The following possibilities exist to reduce the incidence of this
resonance.
– In practice, one tries to put the start-stop frequency into a
higher area (ca. 200 Hz and higher), since stepping mo
tors in the lower frequency areas have more resonance
frequencies.
– One can combat it by increasing the start-stop frequency
or through lower phase current.
– Conversion from full-step to half-step or quarter-step op
eration can also provide help.
– It is helpful to always operate the motor with its nominal
load. If that is not possible, the phase current should be
reduced.

Contents and general instructions
XII Festo SEC-ST-48-6-P01-EN en 1507d English
Phase current
Phase current is the current that flows through strand of a
winding. At the maximum phase current, the stepping motor
has its maximum holding torque. The phase current should
be adjusted to the load. That is, it does not always make
sense to set the motor’s maximum phase current. If the motor
is run without load or with a torque lower than its nominal
torque, it can also carry out steps too far or begin to resonate
(see above), which is equivalent to a loss of step.
The set phase current flows at all times through the active
coils of the motor, even when the motor is standing still. An
advantage of this is that the motor has a certain resting
torque and can be loaded with its holding torque during
standstill. Also, the motor is warmed even at standstill. If this
holding torque is not needed in standstill, it makes sense to
reduce the phase current when the motor is at standstill. The
Festo stepping motor controller SEC-ST-48-6-P01 offers this
option.
With these attributes of the stepping motor considered, it
provides an economical positioning variant with adequate
precision.

Contents and general instructions
XIII
Festo SEC-ST-48-6-P01-EN en 1507d English
Procedure for correctly adjusting the stepping motor
Determining the possible speed with known load
If the torque of the load on the drive is known, the possible
speed can be determined from the speed-torque character
istic curve.
The highest usable speed is the one where the resulting
torque is about 80% of the maximum torque. Beyond that,
the motor’s loss of torque is so great that the danger of losing
steps increases.
Resonance Increased incidence of resonance can be expected in full-step
operation. Since this always depends on the system, it cannot
always be precisely determined where resonance will occur.
Here it is necessary to test.
In general, it is advantageous to run at half-step to reduce
resonance. Current should be reduced when the motor is run
without load. Current that is set too high can also cause res
onance and thus a loss of step.

Contents and general instructions
XIV Festo SEC-ST-48-6-P01-EN en 1507d English
Example
S1
S2
Fig. 0/1: Upper graph S1 - full step / lower graph S2 - half step
M = Torque, n = Speed
The characteristic curve shows the maximum speed that can
be run at full or half step, depending on the set torque (in the
example around 1100 RPM at half step).
Determining the start-stop frequency
It is advantageous to set the start-stop frequency as high as
possible since resonance leading to losses of step can occur
especially in the lower frequency areas.
The start-stop frequency is increased until the drive loses
steps when starting. Then the start-stop frequency is reduced
again by a good 20% to ensure that no steps are lost during
acceleration. A starting value of 400 Hz for small drives and
around 200 Hz for large drives can be assumed.

Contents and general instructions
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Festo SEC-ST-48-6-P01-EN en 1507d English
How can incidences of resonance be suppressed?
Tips and tricks!
Half step instead of full step.
Half step here is better than full step. The two-phase step
ping motor shows generally good run characteristics at
half step.
Set phase current lower (to the value actually required).
While this reduces the system’s stiffness, it also reduces
its tendency to oscillate.
Operating frequencies not equal to resonance frequen
cies.
The operating frequency is often near the resonance fre
quency or is a multiple of it. Small deviations from the
”critical” step frequency usually show good results.
Make the acceleration ramps steeper.
The stepping motor is ”pulled” through the critical areas
quickly and so does not tend so quickly to oscillate.
Increase the friction (emergency solution)
Friction dampens the entire system, but useful torque is
lost.

Contents and general instructions
XVI Festo SEC-ST-48-6-P01-EN en 1507d English
Important user instructions
Danger categories
This manual contains instructions on the possible dangers
which may occur if the product is not used correctly. These
instructions are marked (Warning, Caution, etc), printed on a
shaded background and marked additionally with a picto
gram. A distinction is made between the following danger
warnings:
Warning
This means that failure to observe this instruction may
result in serious personal injury or damage to property.
Caution
This means that failure to observe this instruction may
result in personal injury or damage to property.
Please note
This means that failure to observe this instruction may
result in damage to property.
The following pictogram marks passages in the text which
describe activities with electrostatically sensitive compo
nents.
Electrostatically sensitive components may be damaged if
they are not handled correctly.

Contents and general instructions
XVII
Festo SEC-ST-48-6-P01-EN en 1507d English
Marking special information
The following pictograms mark passages in the text contain
ing special information.
Pictograms
Information:
Recommendations, tips and references to other sources of
information.
Accessories:
Information on necessary or useful accessories for the Festo
product.
Environment:
Information on environment-friendly use of Festo products.
Text markings
The bullet indicates activities which may be carried out in
any order.
1. Figures denote activities which must be carried out in the
numerical order specified.
– Hyphens indicate general activities.

Contents and general instructions
XVIII Festo SEC-ST-48-6-P01-EN en 1507d English
Trademarks
All product names in this documentation are registered trade
marks. All trademarks in this documentation are only used for
identifying the relevant product.
Safety instructions
Please note
The relevant safety instructions and accident-prevention
regulations valid for each specific application must be
observed during installation, commissioning and
maintenance.
The following precautionary measures also apply without
claim to completeness:
Regulations for setting up high-voltage systems up to
1000 volts.
Electrical equipment for machines.
Equipping high-voltage systems with electronic operat
ing media.

System summary
1-1Festo SEC-ST-48-6-P01-EN en 1507d English
Chapter 1

1. System summary
1-2 Festo SEC-ST-48-6-P01-EN en 1507d English
Contents
1.1 Overview 1-3......................................................
1.2 Performance characteristics 1-3......................................
1.3 Controller part 1-4.................................................
1.3.1 Brief description 1-4........................................
1.4 Final output stage 1-4..............................................
1.4.1 Brief description 1-4........................................
1.4.2 Internal monitoring 1-4......................................
1.5 Displays 1-5......................................................
1.5.1 Ready-to-operate display 1-5.................................
1.5.2 Fault display 1-5............................................
1.6 User interfaces 1-6.................................................
1.6.1 Enable input 1-6............................................
1.6.2 Direction input 1-7..........................................
1.6.3 Clock input 1-8.............................................
1.6.4 Fault output 1-9............................................
1.7 Settings 1-10.......................................................
1.7.1 The step mode 1-10..........................................
1.7.2 The current setting 1-12......................................
1.7.3 The current reduction I-red 1-13................................
1.7.4 Enable switch 1-13...........................................
1.7.5 The buttons 1-14............................................