National Instruments NI 9503 User manual

USER MANUAL AND SPECIFICATIONS
NI 9503
Stepper Drive
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2|ni.com |NI 9503 User Manual and Specifications
This document describes how to use the National Instruments 9503
module and includes specifications and pin assignments for the
NI 9503. Visit ni.com/info and enter rdsoftwareversion to
determine which software you need for the modules you are using.
For information about installing, configuring, and programming the
system, refer to the system documentation. Visit ni.com/info and
enter cseriesdoc for information about C Series documentation.
Note The safety guidelines and specifications in this
document are specific to the NI 9503. The other
components in the system may not meet the same safety
ratings and specifications. Refer to the documentation for
each component in the system to determine the safety
ratings and specifications for the entire system.
Safety Guidelines
Operate the NI 9503 only as described in these operating
instructions.
Hot Surface This icon denotes that the component may
be hot. Touching this component may result in bodily
injury.

NI 9503 User Manual and Specifications |© National Instruments |3
Caution Do not operate the NI 9503 in a manner not
specified in these operating instructions. Product misuse
can result in a hazard. You can compromise the safety
protection built into the product if the product is damaged
in any way. If the product is damaged, return it to
National Instruments for repair.
Safety Guidelines for Hazardous Locations
The NI 9503 is suitable for use in Class I, Division 2, Groups A, B,
C, D, T4 hazardous locations; Class I, Zone 2, AEx nA IIC T4, and
Ex nA IIC T4 hazardous locations; and nonhazardous locations
only. Follow these guidelines if you are installing the NI 9503 in a
potentially explosive environment. Not following these guidelines
may result in serious injury or death.
Caution Do not disconnect I/O-side wires or connectors
unless power has been switched off or the area is known
to be nonhazardous.
Caution Do not remove modules unless power has been
switched off or the area is known to be nonhazardous.

4|ni.com |NI 9503 User Manual and Specifications
Caution Substitution of components may impair
suitability for Class I, Division 2.
Caution For Division 2 and Zone 2 applications, install
the system in an enclosure rated to at least IP 54 as
defined by IEC 60529 and EN 60529.
Caution For Division 2 and Zone 2 applications, install
a protection device between the input signal and the Vsup
pin. The device must prevent the Vsup-to-channel voltage
from exceeding 42 V if there is a transient overvoltage
condition.
Caution For Zone 2 applications, connected signals
must be within the following limit:
Capacitance.......................... 0.2 μF max
Special Conditions for Hazardous Locations Use in
Europe
This equipment has been evaluated as Ex nA IIC T4 Gc equipment
under DEMKO Certificate No. 12 ATEX 1202658X. Each module
is marked II 3G and is suitable for use in Zone 2 hazardous
locations, in ambient temperatures of -40 °C ≤Ta ≤70 °C. If you are

NI 9503 User Manual and Specifications |© National Instruments |5
using the NI 9503 in Gas Group IIC hazardous locations, you
must use the device in an NI chassis that has been evaluated as
Ex nC IIC T4, EEx nC IIC T4, Ex nA IIC T4, or Ex nL IIC T4
equipment.
Caution You must make sure that transient disturbances
do not exceed 140% of the rated voltage.
Caution The system shall be mounted in an ATEX
certified enclosure with a minimum ingress protection
rating of at least IP54 as defined in IEC/EN 60529 and
used in an environment of not more than Pollution
Degree 2.
Caution The enclosure must have a door or cover
accessible only by the use of a tool.
Electromagnetic Compatibility Guidelines
This product was tested and complies with the regulatory
requirements and limits for electromagnetic compatibility (EMC)
as stated in the product specifications. These requirements and
limits are designed to provide reasonable protection against

6|ni.com |NI 9503 User Manual and Specifications
harmful interference when the product is operated in its intended
operational electromagnetic environment.
This product is intended for use in industrial locations. As such,
there is no guarantee that harmful interference will not occur in
a particular installation, when the product is connected to a test
object, or if the product is used in residential areas. To minimize
the potential for the product to cause interference to radio and
television reception or to experience unacceptable performance
degradation, install and use this product in strict accordance with
the instructions in the product documentation.
Furthermore, any changes or modifications to the product not
expressly approved by National Instruments could void your
authority to operate it under your local regulatory rules.
Caution To ensure compliance with the applicable
regulatory requirements, product installation requires
either special considerations or user-installed, add-on
devices. See the product installation instructions for
further information.

NI 9503 User Manual and Specifications |© National Instruments |7
Caution The inputs/outputs of this product can be
damaged if subjected to Electrostatic Discharge (ESD).
To prevent damage, industry-standard ESD prevention
measures must be employed during installation,
maintenance, and operation.
Special Guidelines for Marine Applications
Some products are Lloyd’s Register (LR) Type Approved for
marine (shipboard) applications. To verify Lloyd’s Register
certification for a product, visit ni.com/certification and
search for the LR certificate, or look for the Lloyd’s Register mark
on the product label.
Caution In order to meet the EMC requirements for
marine applications, install the product in a shielded
enclosure with shielded and/or filtered power and
input/output ports. In addition, take precautions when
designing, selecting, and installing measurement probes
and cables to ensure that the desired EMC performance is
attained.

8|ni.com |NI 9503 User Manual and Specifications
NI 9503 Hardware Overview
The NI 9503 is a stepper motor drive for use with 2-phase hybrid
stepper motors in either bipolar or unipolar winding configuration.
It uses software-programmable control algorithms that reduce
torque ripple, dampen high-speed resonance, and implements
smoother motion during microstepping.
The NI 9503 returns the motor current and bus voltage to the
LabVIEW FPGA module for use in a current PI loop and
antiresonance algorithms. NI 9503 status information such as drive
status and drive faults are also returned to the LabVIEW FPGA
module. Refer to the NI 9503 topic in the LabVIEW Help, available
by selecting Help»LabVIEW Help, for information about the
available status information.
Note National Instruments offers NEMA 8, NEMA 11,
NEMA 14, NEMA 17 and NEMA 23 stepper motors
compatible with the NI 9503. Go to ni.com/motion/
stepper for more information about NI stepper motors.
The NI 9503 reduces torque ripple at speeds near 1 RPS that are
caused by fourth harmonic disturbances. The torque ripple
smoothing algorithm is software programmable and can be tuned

NI 9503 User Manual and Specifications |© National Instruments |9
for any motor. Motors supported by National Instruments have
already been tuned for optimal torque smoothing.
The NI 9503 uses a software-programmable antiresonance
algorithm to reduce stepper motor resonance above 2 RPS. The
antiresonance algorithm allows a stepper motor to use more
available torque and run at higher speeds without stalling.
The NI 9503 supports software-programmable microstepping.
Microstepping divides full steps into smaller steps to create
smoother motion. The NI 9503 supports microstepping rates up to
256. When full-stepping, a resonance can occur, causing vibration
and reducing the motor torque. The NI 9503 offers the best
performance when combining microstepping with the torque
smoothing and antiresonance properties. Refer to the Step Resolver
topic in the LabVIEW Help, available by selecting Help»
LabVIEW Help, for information about microstepping options.
The NI 9503 allows for phase current reduction after the motor
stops moving. Unlike servo motors, stepper motor coils remain
fully energized when the motor is not moving. This allows for
strong holding torque, but generates substantial heat in the motor.
Many applications do not require maximum holding torque when
the motor is at rest, which means that the motor is wasting power.
The amount of current reduction and delay before current

10 |ni.com |NI 9503 User Manual and Specifications
reduction becomes active is software-programmable. Refer to the
Current Scheduler topic in the LabVIEW Help, available by
selecting Help»LabVIEW Help, for information about current
reduction.
Figure 1. NI 9503 Block Diagram
Current
Scheduler
Step
Resolver
Current
Loop
Fault
Monitor
Bridge
Controller
Fault
Detection
Current
Sense
Motor
Position
Setpoint
LabVIEW FPGA Module with SoftMotion NI 9503
Phase A & B
Current
PWM
Generator
Anti-
resonance
Bus
voltage
Power
Stage
Vsup
COM
+
–
Correction
Angle

NI 9503 User Manual and Specifications |© National Instruments |11
Connecting the NI 9503
The NI 9503 has a 10-terminal detachable screw-terminal
connector that provides connections for the stepper motor signals,
a motor DC power supply, COM, and chassis ground. Refer to
Figure 2 for the pin assignments.
Caution To ensure EMC compliance, special
considerations are required for all cable connections.
Refer to the Cable Requirements for EMC Compliance
section.
Note You must use 2-wire ferrules to create a secure
connection when connecting more than one wire to a
single terminal on the NI 9503 screw terminal.
Caution Do not turn on or plug in the motor DC power
supply until the screw-terminal connector is fully
inserted.

12 |ni.com |NI 9503 User Manual and Specifications
Figure 2. NI 9503 Connections
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
(Chassis Ground)
0
1
2
3
4
5
6
7
8
9

NI 9503 User Manual and Specifications |© National Instruments |13
Motor Power Signals
The Phase A± and Phase B± signals power the stepper motor.
Figure 3 shows a typical bipolar stepper motor connection.
Figure 3. Typical Bipolar Stepper Motor (2-Phase Type) Connection
Caution The stepper motor terminals on this drive are
energized when the module is enabled. Do not connect
wires to or disconnect wires from the NI 9503 when it
is enabled.
Use a multiconductor cable with an overall shield and conductors
of 20 AWG or larger for the motor power cable.
0
1
2
3
4
5
6
7
8
9
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
Phase A+
Phase A–
Phase B+
Phase B–
Red
Blue
Yellow
White

14 |ni.com |NI 9503 User Manual and Specifications
The NI 9503 contains a highly efficient power stage. Two-phase
stepper motors come in 4-, 6-, and 8-wire variations. You must wire
the stepper motors in a 4-wire configuration as shown in Figure 3.
Caution Never connect unused stepper motor terminals
to pin 9 (Chassis Ground) or to each other.
When using a 6- or 8-wire stepper motor you must leave unused
lead wires disconnected. Figure 4 shows a 6-wire and an 8-wire
stepper motor.
Figure 4. 6-Wire and 8-Wire Stepper Motors
6-wire 8-wire

NI 9503 User Manual and Specifications |© National Instruments |15
A 4-wire motor is the same as a 6-wire motor except that the center
taps (CT) are not brought out. To use a 6-wire motor in a 4-wire
configuration you can isolate the center taps for a series (full coil)
configuration. Series configurations produce the most torque per
amp but have the disadvantage of poorer high-speed performance.
Figure 5. 6-Wire Series Stepper Motor Connection
(Higher Torque, Lower Speed)
0
1
2
3
4
5
6
7
8
9
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
Phase A+
Phase A–
Phase B+
Phase B–
NC*
NC*
*NC = Not Connected

16 |ni.com |NI 9503 User Manual and Specifications
You can obtain improved high-speed performance with a 6-wire
motor by using a half-coil configuration shown in Figure 6. This
configuration sacrifices low-speed torque for better high-speed
performance. With this configuration, it is typically not possible to
produce the rated torque of the motor without the risk of the motor
overheating because only half of the windings are used.
Figure 6. 6-Wire Half-Coil Stepper Motor Connection
(Higher Speed, Lower Torque)
0
1
2
3
4
5
6
7
8
9
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
Phase A+
Phase A–
Phase B+
Phase B–
NC*
NC*
*NC = Not Connected

NI 9503 User Manual and Specifications |© National Instruments |17
For maximum flexibility, you can connect 8-wire stepper motors
in series, parallel, or half-coil configurations. Connecting the
windings in a series configuration, as shown in Figure 7, produces
the most torque per amp but has the disadvantage of higher
inductance and poorer high-speed performance.
Figure 7. 8-Wire Series Stepper Motor Connection
(Higher Torque, Lower Speed)
Phase B–
0
1
2
3
4
5
6
7
8
9
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
Phase A+
Phase A–
Phase B+
Orange
Org/Wht
Blk/Wht
Black
Red
Red/Wht
Yel/Wht
Yellow

18 |ni.com |NI 9503 User Manual and Specifications
Notice that an 8-wire motor wired in a series configuration is
virtually identical to a 6-wire motor and typically has the same
high torque but low-speed characteristics.
Alternatively, you can connect 8-wire stepper motors in a parallel
configuration as shown in Figure 8. This configuration produces
better high-speed performance but requires more current to
produce rated torque.
Figure 8. 8-Wire Parallel Stepper Motor Connection
(Higher Speed, Lower Torque)
0
1
2
3
4
5
6
7
8
9
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
Phase B–
Phase A+
Phase A–
Phase B+
Orange
Red
Yel/Wht
Red/Wht
Yellow
Black
Org/Wht
Blk/Wht

NI 9503 User Manual and Specifications |© National Instruments |19
Finally, you can connect 8-wire stepper motors in a half-coil
configuration as shown in Figure 9. The half-coil configuration
sacrifices low-speed torque for better high-speed performance.
With this configuration, it is typically not possible to produce the
rated torque of the motor without the risk of the motor overheating
because only half of the windings are used.
Figure 9. 8-Wire Half-Coil Stepper Motor Connection
0
1
2
3
4
5
6
7
8
9
Phase A+
Phase A–
Phase B+
Phase B–
Reserved
Reserved
Reserved
COM
Vsup
Phase B–
Phase A+
Phase A–
Phase B+
NCNC
NC
NC
*NC = Not Connected

20 |ni.com |NI 9503 User Manual and Specifications
Wiring for High Vibration Applications
If an application is subject to high vibration, National Instruments
recommends that you use ferrules to terminate wires to the
detachable screw-terminal connector.
Refer to Figure 10 for an illustration of using ferrules.
Figure 10. 10-Terminal Detachable Screw-Terminal Connector with
Ferrule Terminated Wire
Ferrule