Leadshine Technology Co. EM870S User manual

EM870S Digital Stepper Drive User Manual
User Manual
EM870S
Digital Microstep Drive
Revision 3.1
©2019 Leadshine Technology Co., Ltd.
Address: Motion Control Products Ltd, 11-15 Francis Avenue, Bournemouth, Dorset, BH11 8NX, United Kingdom
Tel: [phone]
Web: www.motioncontrolproducts.com Sales: [e-mail]
Support: [e-mail]

EM870S Digital Stepper Drive User Manual
Important Notice
Read this manual carefully before any assembling and using. Incorrect handling of products in this manual can result
in injury and damage to persons and machinery. Strictly adhere to the technical information regarding installation
requirements.
This manual is not for use or disclosure outside of Leadshine except under permission. All rights are reserved. No part
of this manual shall be reproduced, stored in retrieval form, or transmitted by any means, electronic, mechanical,
photocopying, recording, or otherwise without approval from Leadshine. While every precaution has been taken in
the preparation of the book, Leadshine assumes no responsibility for errors or omissions. Neither is any liability
assumed for damages resulting from the use of the information contained herein.
This document is proprietary information of Leadshine that is furnished for customer use ONLY. Information in this
document is subject to change without notice and does not represent a commitment on the part of Leadshine.
Therefore, information contained in this manual may be updated from time-to-time due to product improvements,
etc., and may not conform in every respect to former issues.
Record of Revisions
Revision
Date
Description of Release
3.0
Jan, 2019
Add Brake, control signal circuit, etc.
3.1
Sep, 2019
Modified the description of filter time setting in Chapter 7.4

EM870S Digital Stepper Drive User Manual
Table of Contents
1. Introduction.................................................................................................................................................................. 1
1.1 Features................................................................................................................................................................ 1
1.2 Applications ......................................................................................................................................................... 1
2. Specifications................................................................................................................................................................ 2
2.1 Electrical Specifications ...................................................................................................................................... 2
2.2 Environment ........................................................................................................................................................ 2
2.3 Mechanical Specifications ................................................................................................................................... 2
2.4 Elimination of Heat.............................................................................................................................................. 3
3. Connection Pin Assignments and LED Indication.................................................................................................... 3
3.1 P1 - Control Connector Configurations ............................................................................................................... 3
3.2 P2 - Fault and Brake Output Connector............................................................................................................... 4
3.3 P3 - Power Connector.......................................................................................................................................... 4
3.4 P4 - Motor Connector .......................................................................................................................................... 4
3.5 P5 - Tuning Port................................................................................................................................................... 4
3.6 Status LED Lights................................................................................................................................................ 4
4. Control Signal and Fault Output ............................................................................................................................... 5
4.1 Control Signal Connection .................................................................................................................................. 5
4.2 Fault and Brake Output Connection .................................................................................................................... 5
5. Stepper Motor Connections ........................................................................................................................................ 6
5.1 4-lead Motor Connection (recommended)........................................................................................................... 6
5.2 6-lead Motor Connection..................................................................................................................................... 6
5.3 8-lead Motor Connection..................................................................................................................................... 7
6.Power Supply Selection ................................................................................................................................................ 7
6.1 Regulated or Unregulated Power Supply............................................................................................................. 7
6.2 Power Supply Sharing ......................................................................................................................................... 8
6.3 Selecting Supply Voltage ..................................................................................................................................... 8
7.DIP Switch Configurations .......................................................................................................................................... 8
7.1 Output Current Configuration (SW1-3) ................................................................................................ 8
7.2 Idle Current Configuration (SW4) ................................................................................................ 9
7.3 Micro Step Configuration (SW5-8) ................................................................................................ 9
7.4 Smoothing Filter Time Configuration (SW9-10)............................................................................................... 10
7.5 No Auto Tuning Configuration (SW11)....................................................................................... 10
7.6 Alarm Output Configuration (SW12) .............................................................................................. 10
7.7 Activated Pulse Edge Configuration (SW13) .................................................................................................... 10
7.8 Control Mode Configuration (SW14)................................................................................................................ 10
7.9 Shaft Lock Configuration (SW15)..................................................................................................................... 10
7.10 Self-Test Configuration (SW16)...................................................................................................... 10
8. Wiring Notes................................................................................................................................................................11
9. Typical Connection .....................................................................................................................................................11
10. Sequence Chart of Control Signals .........................................................................................................................11
11. Protection Functions................................................................................................................................................ 12
12. Troubleshooting ....................................................................................................................................................... 13
13. Warranty .................................................................................................................................................................. 14

EM870S Digital Stepper Drive User Manual
Page | 1
1. Introduction
The EM870S is a new digital stepper drive based on Leadshine’s widely implemented DM stepper drives (10+ millions
of units in field). While retaining features of simple design, easy setup, high precision and reliability, Leadshine has
also upgraded it by adopting the latest stepper control technology and added additional advanced features for better
torque (10-25%), quicker response time, control command smoothing, easy self-test, etc.
The EM870S is able to power 2 phase (1.8°) and 4 phase (0.9°) stepper motors smoothly with very low motor heating
& noise. It can take 20-80VDC supply voltage and output 0.5 to 7.0A current. All the micro step and output current
configurations can be easily done via built in DIP switches. Its control type (step & direction or CW/CCW) and
command smooth filtering can also be configured via DIP switches. Therefore, the EM870S is an ideal choice for
many applications requiring simple step & direction or CW/CCW control of NEMA 23, NEMA24 and NEMA 34
(lower than and including 4.5N.m motors) stepper motors.
1.1 Features
Step & direction (PUL/DIR) or CW/CCW (double pulse) control
20-80VDC supply voltage
200 KHz (500KHz optional) max pulse input frequency
16 microstep resolutions of 200-25,600 via DIP switches, or 200-51,200 via software (increase by 200)
8 output current settings of 1.4 -7.0A via DIP Switches, or 0.5-7.0A via software (increase by 0.1)
Configurable control command smoothing for reducing motor vibration
Idle current reduction to 50% or 90% selection via SW4
Convenient self-test for easy diagnosis
Auto-tuning to match wide-range NEMA 23, 24, 34 stepper motors
Anti-Resonance for optimal torque, extra smooth motion, low motor heating and noise
Soft-start with no “jump” when powered on
Optically isolated inputs with 5V or 24V
Fault and Brake output
Over-voltage, over-current and motor cable error protections
CE certified and RoHS compliant
1.2 Applications
The EM870S stepper drive is designed to power 2 phase (1.8°) or 4-phase (0.9°) NEMA23, 24 and 34 hybrid stepper
motors. It can be adopted in many industries (CNC machinery, electronics, medical, automation, packaging…) for
applications such as CNC routers, mills, plasma, laser cutters, factory assembly lines, vending machines, etc. Its
excellent performance, simple design, and easy setup features make EM870S ideal for many step & direction control
type applications.

EM870S Digital Stepper Drive User Manual
Page | 2
2. Specifications
2.1 Electrical Specifications
Parameters
Min
Typical
Max
Unit
Output Current
0.5
-
7.0 (5.0 RMS)
A
Supply Voltage
20
24 - 72
80
VDC
Logic signal current
7
10
16
mA
Pulse input frequency 0 - 200 kHz
Minimal pulse width 2.5 - - μs
Minimal direction setup 5.0 - - μs
Isolation resistance
500
-
-
MΩ
2.2 Environment
Cooling
Natural Cooling or Forced cooling
Operating Environment
Environment
Avoid dust, oil fog and corrosive gases
Ambient Temperature
0
－
65°C (32 - 149°F)
Humidity
40
－
90%RH
Operating Temperature
0
－
50°C (32 - 122°F)
Vibration
10-50Hz / 0.15mm
Storage Temperature -20°C －65°C (-4°F - 149°F)
Weight Approx. 250g (8.8 oz)
2.3 Mechanical Specifications
(unit: mm [1inch=25.4mm])
Figure 1 Mechanical specifications
* Side mounting recommended for better heat dissipation

EM870S Digital Stepper Drive User Manual
Page | 3
2.4 Elimination of Heat
EM870S’s working temperature is less than 60℃(140°F)
It is recommended to use automatic idle-current mode to reduce motor heating. That means set the SW4 pin of
DIP switch at “OFF” position.
It is recommended to mount the drive vertically to maximize heat sink area. Use forced cooling method to cool if
necessary.
3. Connection Pin Assignments and LED Indication
P4:Motor Connector
S1:DIP Switch
Selector 1
P3:Power Connector P2:Fault and Brake Outputs
P1:Control Signal Inputs
Status LEDs
S2:DIP Switch Selector 2
P5:Tuning Port
S3:Control Signal Voltage Selector
(5V or 24V)
Figure 2 Connectors, DIP switches, and LED locations
The EM870S has 5 connectors P1, P2, P3, P4 and P5, 3 DIP switches S1, S2 and S3. P1 is for control signal
connections, P2 is for fault output, P3 is for power connection, P4 is for motor connection and P5 is for fine tuning.
3.1 P1 - Control Connector Configurations
PIN
Details
PUL+ (CW+)
Pulse and Direction Connection:
(1) Optically isolated, high level 4.5-5V or 24V, low voltage 0-0.5V
(2) Maximum 200 KHz input frequency, 500KHz customized model is available
(3) The width of PUL signal is at least 2.5μs, duty cycle is recommended 50%
(4) Single pulse (step & direction) or double pulse (CW/CCW) is set by DIP Switch SW14
(5) DIR signal requires advance PUL signal minimum 5 μs in single pulse mode
(6) The activated edge of PUL and DIR is set by DIP Switch SW13
(7) The factory setting of control signal voltage is 24V, must need to set S3 (figure 2) if it is 5V
PUL-(CW-)
DIR+ (CCW+)
DIR-(CCW-)
ENA+
Enable Connection: Optional.
(1) Optically isolated, differential.
(2) Disable the drive by 4.5-5.0V or 24V input connection; enable the drive by 0-0.5V
connection(default no connection)
(3) ENA signal requires advance DIR signal minimum 5μs in single pulse mode
(4) The default control signal voltage is 24V, to set S3 (figure 2) if it is 5V
(5) Enable time to be at least 200ms
ENA-

EM870S Digital Stepper Drive User Manual
Page | 4
!
Notice
Notes: (1) shield cables are required for P1; (2) don’t tie P1/P2 cables and P3/P4 cables together.
3.2 P2 - Fault and Brake Output Connector
Pin Details
ALM Output Connection: Optional.
(1) Maximum 30V/100mA output
(2) Sinking or sourcing
(3) The resistance between ALM and COM- is low impedance as default (configurable by DIP
switch SW12), and will change to high when the drive goes into error protection.
(4) Fault and Brake connection refer to chapter 4.2
BR
COM-
3.3 P3 - Power Connector
Pin Details
GND Connect to power supply ground connection.
+VDC
Connect to power supply positive connection. Suggest 24-72VDC power supply voltage
!
Warning
Warning: Don’t plug/unplug P3 or P4 connector to avoid drive damage or injury while powered on.
3.4 P4 - Motor Connector
PIN
Details
A+
Connect to motor A+ wire
A-
Connect to motor A- wire
B+
Connect to motor B+ wire
B- Connect to motor B- wire
3.5 P5 - Tuning Port
EM556S has a tuning port with RS232 to modify the drive parameters, it’s only for tuning, not for equipment control
because neither precision nor stability is sufficient. If you need a field bus drive, contact Motion Control Products Ltd.
For their range of fieldbus servo drives and stepper drives, ideal for performance network control.
www.motioncontrolproducts.com
The interface definition is as follows:
3.6 Status LED Lights
There are two LED lights for EM870S. The GREEN one is the power indicator which should be always on in normal
circumstance. The RED one is a drive status indication light, which will be OFF while working normally but ON and

EM870S Digital Stepper Drive User Manual
Page | 5
flash 1 or 2 times in a 3-second period in the case of enabled over-current or over-voltage protection.
4. Control Signal and Fault Output
4.1 Control Signal Connection
The EM870S can accept differential or single-ended control signals (pulse, direction, and enable) in open-collector or
PNP connection through the P1 connector (figure 2). It is recommend to add an EMI line filter between the power
supply and the drive to increase noise immunity for the drive in interference environments.
Controller
PUL+ 1
DIR+ 3
PUL-
DIR-
2
4
ENA+ 5
ENA- 6
Step
Direction
Enable
VCC
VCC
VCC
Drive
Controller Drive
PUL+ 1
DIR+ 3
PUL-
DIR-
2
4
ENA+ 5
ENA- 6
VCC
Step
Direction
Enable
Figure 3 Connections to open-collector signals Figure 4 Connections to PNP signals
(Common-anode) (Common-cathode)
4.2 Fault and Brake Output Connection
•Fault Output
When over voltage or over current protection happens, EM870S red status LED light will blink and the impedance
state between ALM and COM- will change (from low to high or high to low depending on configuration) and can thus
be detected. Fault output connection is optional, and it can be connected either in sinking or sourcing.
ALM
Drive
COM-
Load
5-24VDC
ALM
Drive
COM-
Load
5-24VDC
Figure 5 Sinking output Figure 6 Sourcing output
•Brake Control
It is recommended to connect a fly-wheel diode in parallel to a 24VDC relay and brake coil connection. Refer to the
following figure for brake connection.

EM870S Digital Stepper Drive User Manual
Page | 6
+24VDC
GND
Drive
BR
COM-
Brake
Coil
24VDC
Relay
Figure 7Brake Output Connection
5. Stepper Motor Connections
EM870S can drive 2-phase and 4-phase bipolar hybrid stepper motors with 4, 6, or 8 leads, Leadshine also offers
easy-to-use and good-performance motors with 4-lead that have been tested with EM870S:
https://www.motioncontrolproducts.com/electric-motors/stepper-motors/hybrid-stepper-motors/
5.1 4-lead Motor Connection (recommended)
4-lead motor is easy to use with excellent performance. Refer to figure 8 for how to connect a 4-lead stepper motor.
P4
Figure 84-lead Motor Connection
5.2 6-lead Motor Connection
EM870S can power 6-lead stepper motors through half coil connection (half chopper) or full coil (full copper)
connection. The half coil connection only uses one half of the motor’s winding and is usually selected in applications
requiring high speed but lower torque. The full coil connection uses the full coil winding and is usually selected in
high-torque required applications. Refer to figure 9 and 10 for those two connections.
P4
P4

EM870S Digital Stepper Drive User Manual
Page | 7
Figure 9 6-lead motor half coil connection Figure 10 6-lead motor full coil connection
5.3 8-lead Motor Connection
EM870S can power 8-lead in series or parallel connection in series or parallel.
Series connected 8-lead stepper motors are typically implemented in applications which higher torque at lower speed
movement is required. Because a stepper motors under series connection has the most inductance, the performance will
start to degrade when the motor runs at higher speed. For this connection, it is suggested to set an EM870S’s output
RMS current to no more than 70% of the stepper motor’s phase current to prevent overheating. See the figure 11 for
how to connect an 8-lead stepper motor for series connection.
Parallel connected 8-lead stepper motors are typically implemented in applications which higher torque at high speed
movement is required. Compared with series connection, a parallel connected stepper motor has lower inductance and
therefore have better torque performance at higher speed movement. Although setting the drive output current to 1.4
times of driven motor phase current will get the most torque, it is suggested to set an EM870S’s output current (peak of
sinusoidal) to no more than 1.2 times the stepper motor’s phase current to prevent overheating. Refer to the figure 12
for how to connect an 8-lead stepper motor for parallel connection.
P4
P4
Figure 11 8-lead motor series connection Figure 12 8-lead motor parallel connection
6. Power Supply Selection
EM870S is designed to power stepper motors (frame sizes NEMA 23 to 34) made by Leadshine or other motor
manufacturers. To get optimal performances, it is important to select proper power supply type, voltage, and supply
output current. In general power supply voltage determines the high speed performance of a stepper motor, while drive
output current determines the driven motor torque output. Higher supply voltage can increases motor speed torque
performance, but at the same time result in more noise and motor heating. For low motor speed applications, it is
suggested to use lower supply voltage power supplies.
6.1 Regulated or Unregulated Power Supply
Both regulated and unregulated power supplies can be used to power an EM870S. Theoretically unregulated power
supplies are preferred due to their ability to withstand back EMF current surge and faster response for current change.
If you prefer to use a regulated power supply instead, it is suggested to choose one specially designed for stepper or
servo controls such as one Leadshine RPS series power supply:
http://www.leadshine.com/ProductSubType.aspx?type=products&category=other-products&producttype=power-suppli
es&subtype=regulated-switching-power-supplies.In the case when only general purpose switching power supplies are
available, choose one with “OVERSIZED” current output rating (for example, using a 4A power supply for 3A stepper
motor) to avoid current clamp. On the other hand, if unregulated supply is used, one may use a power supply of lower

EM870S Digital Stepper Drive User Manual
Page | 8
current rating than that of motor (typically 50% - 70% of motor phase current). The reason is that the drive only draws
current from an unregulated power supply during the ON duration of the PWM cycle, but not during the OFF duration.
6.2 Power Supply Sharing
Multiple EM870S drives can share the same power supply, if that power supply has enough capacity. To avoid cross
interference, connect each EM870S DIRECTLY to that shared power supply separately instead of connecting those
power connectors of drives in daisy-chain connection.
6.3 Selecting Supply Voltage
EM870S’s operating voltage is 20-80 VDC. Because of voltage increasing from potential power line voltage
fluctuation and back EMF voltage generated during motor deceleration, it is suggested to use a 24-72 VDC power
supply.
7. DIP Switch Configurations
The EM870S has two 8-bit and one 1-bit DIP switch selector.“Default”means that parameters can be modified by
Leadshine PC software software.
The first 8-bit is located on the side (DIP switch selector 1 in Figure 2) and used to configure settings of micro step
resolution, output current, and motor standstill current as shown below, the factory setting of SW1-SW8 is OFF, OFF,
OFF, OFF, OFF, OFF, ON, ON.
SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8
The second 8-bit DIP switch is located on the top (DIP switch selector 2 in figure 2), and used to configure settings of
control command filtering time, motor auto-configuration, fault output impedance, pulse active edge, control mode,
lock shaft, and self-test as shown below, the factory setting of SW1-SW8 is OFF, OFF, OFF, ON, ON, OFF, OFF, OFF.
The Third 1-bit selector is located on the top (DIP switch selector 3 in figure 2), used to configure the voltage of
control signals. For the safety of optically coupled, the factory setting is 24V, which no need to connect 2K resistors
like the old drives, making it easier to use. When the voltage of the control signal is 5V, the S3 must be set to 5V，
otherwise, the motor won't work.
7.1 Output Current Configuration (SW1-3)
The EM870S has 8 output current settings which can be configured through DIP switch SW1, SW2 and SW3.
For a given stepper motor, as normal setting the output current to 1.4 times of motor phase current, will make it output
larger torque, but at the same time cause more heating for both the motor and drive. Therefore, it is suggested to set a
Idle Current
Output Current Microstep

EM870S Digital Stepper Drive User Manual
Page | 9
output current (peak of sinusoidal) to no more than 1.2 times the stepper motor’s (for 4-lead motor) phase current to
prevent overheating .
The SW1, SW2 and SW3 are used to set the dynamic current. Select a setting closest to your motor’s required current.
When they are set to ON, ON, ON, the output current can be set by Leadshine PC software.
Peak Current RMS Current SW1 SW2 SW3
1.4A 1.0A (default) OFF OFF OFF
2.6A 1.8A ON OFF OFF
3.4A 2.4A OFF ON OFF
4.0A 2.8A ON ON OFF
4.8A 3.4A OFF OFF ON
5.4A 3.8A ON OFF ON
6.1A 4.3A OFF ON ON
7.0A 5.0A ON ON ON
7.2 Idle Current Configuration (SW4)
The SW4 of an EM870S is used to set output current percentage when motor is standstill. Idle current percentage will
be set to 50% at OFF position, and 90% at ON position. When the driven stepper motor is idle (no movement) for 0.4
second, the output current of EM870S will be automatically reduced to the configured percentage.
7.3 Micro Step Configuration (SW5-8)
Each EM870S has 16 micro step settings which can be configured through DIP switch SW5, SW6, SW7 and SW8. See
the following table for detail. When they are set to ON, ON, ON,ON, the microstep can be set via Leadshine PC
software.
Micro step Pulses/Rev. (for 1.8°motor) SW5 SW6 SW7 SW8
1 200 (default) ON ON ON ON
2 400 OFF ON ON ON
4 800 ON OFF ON ON
8 1600 OFF OFF ON ON
16 3200 ON ON OFF ON
32 6400 OFF ON OFF ON
64 12800 ON OFF OFF ON
128 25600 OFF OFF OFF ON
5 1000 ON ON ON OFF
10 2000 OFF ON ON OFF
20
4000
ON
OFF
ON
OFF
25 5000 OFF OFF ON OFF
40 8000 ON ON OFF OFF
50 10000 OFF ON OFF OFF
100 20000 ON OFF OFF OFF

EM870S Digital Stepper Drive User Manual
Page | 10
125 25000 OFF OFF OFF OFF
7.4 Smoothing Filter Time Configuration (SW9-10)
EM870S has an advanced feature called control command smoothing to make the input pulse from pulse generator
(controller, PLC, etc.) S-curve acceleration, to improve motion smoothness and high-speed start frequency in many
circumstances.
This is achieved through adding filtering time which is configured SW9-SW10. See the following table for how to
configure.
Filter Time SW9 SW10
0 ms (disabled) ON ON
6 ms OFF ON
12 ms ON OFF
25 ms OFF OFF
!
Warning
The Filter Time value must be set to the same for each EM870S in multi-axis applications
7.5 No Auto Tuning Configuration (SW11)
EM870S can configure itself with the best match to the driven stepper motor. This feature may need to be disabled for
some applications or when it is used to drive a specially designed stepper motor. To do that, set the DIP switch SW11
to ON position and the drive will be set to its default settings.
7.6 Alarm Output Configuration (SW12)
DIP switch SW12 is used to configure the impedance state of alarm output (fault output). At OFF position (factory
setting) the resistance between ALM and COM- is set to low impedance in normal operation, and will change to high
impedance when the drive goes into fault. When SW12 is set to ON position, that resistance will be set to high
impedance in normal condition and changed to low impedance under error protections.
7.7 Activated Pulse Edge Configuration (SW13)
DIP switch SW13 is used to configure pulse edge. Set it to OFF position (factory setting) means that a pulse is
activated at voltage rising edge, and ON position means a pulse is activated at falling edge. Make sure this setting will
match the pulse generator (controller, PLC, etc.). When the stepper motors loss step, first reverse the SW13 for a test.
7.8 Control Mode Configuration (SW14)
DIP switch SW14 is used to configure the control mode. Factory setting is single pulse (step & direction, or pulse &
direction) control. Setting to ON to change the control model to double pulse (CW/CCW) control type.
7.9 Shaft Lock Configuration (SW15)
Use DIP switch SW15 to set shaft lock mode when EM870S is disabled (read ENA+ and ENA- explanation of control
connector for how to disable EM870S). Set it to OFF position (default) for no motor shaft lock (free spin) when drive
disabled. Set it to ON position for motor shaft lock.
7.10 Self-Test Configuration (SW16)
For test and system diagnosis purpose, EM870S is featured with Self-Test. Anytime SW16 is switched to ON position,

EM870S Digital Stepper Drive User Manual
Page | 11
the drive will automatically rotate the driven stepper motor back and forth for one round in each direction. Set this
switch position to OFF for normal operation.
8. Wiring Notes
In order to improve anti-interference performance of the drive, it is recommended to use twisted pair shield cable.
To prevent noise incurred in PUL/DIR signal, pulse/direction signal wires and motor wires should not be tied up
together. It is better to separate them by at least 10 cm; otherwise the disturbing signals generated by motor will
easily disturb pulse direction signals, causing motor position error, system instability and other failures.
If only one power supply serves multiple EM870S drives, separately connecting the drives to the power supply is
recommended instead of daisy-chaining.
It is prohibited to pull and plug connector P3&P4 while the drive is powered ON, because there is high current
flowing through motor coils (even when motor is at standstill). Pulling or plugging connector P4 with power on
will cause extremely high back-EMF voltage surge, which may damage the drive.
9. Typical Connection
A complete stepping system should include stepping motor, stepping drive, power supply and controller (pulse
generator). A typical connection is shown as figure 12.
GND
A+
A-
+Vdc
1
5
6
Power &
Motor Connector
Controller
Control Signal
Connector
4
PUL+ 1
DIR+ 3
PUL-
DIR-
2
4
ENA+ 5
ENA- 6
Step
Direction
Enable
Fault
BR
1
2
COM-
Status Signal
Connector
24-48VDC recommended,
leaving rooms for voltage fluctuation
and back EMF of the motor
2
3B+
B-
Drive
ALM
3
Brake
BR
Figure 12 Typical connection
10. Sequence Chart of Control Signals
In order to avoid some fault operations and deviations, PUL, DIR and ENA should abide by some rules, shown as

EM870S Digital Stepper Drive User Manual
Page | 12
following diagram:
Figure 13 Sequence chart of control signals
Remark:
a) t1: ENA must be ahead of DIR by at least 500ms for auto-tuning. Usually, ENA+ and ENA- are NC (not
connected). See “Connector P1 Configurations” for more information.
b) t2: DIR must be ahead of PUL effective edge by 5µs to ensure correct direction;
c) t3: Pulse width not less than 2.5µs, duty cycle recommend 50%
d) t4: Low level width not less than 2.5µs
11. Protection Functions
EM870S incorporates are built with over-voltage and over-current error protections. When it is under error
protection, the red LED light will blink for 1 or 2 or 4 times in a period of 3 seconds. If fault output connection is
connected, the impedance mode between ALM+ and ALM- will be changed (See “Fault Output Configuration”
section for detail).
Prio
rity
Time(s) of
Blink Sequence wave of red LED Description
1st Always on The drive was short-circuited or burned out.
1st 1
Over-current protection activated when peak
current exceeds the limit.
2nd 2
Over-voltage protection activated when drive
working voltage is greater than 92VDC
3rd 4 Motor cable error o
r not connected to the motor.
Figure 14 Error Protections
When over-current and over-voltage protections are activated, the motor shaft will be free or the red LED blinks. Reset
the drive by restart it to make it function properly after removing above problems.

EM870S Digital Stepper Drive User Manual
Page | 13
12. Troubleshooting
In the event that your drive doesn’t operate properly, the first step is to identify whether the problem is electrical or
mechanical in nature. The next step is to isolate the system component that is causing the problem. As part of this
process you may have to disconnect the individual components that make up your system and verify that they operate
independently. It is important to document each step in the troubleshooting process. You may need this documentation
to refer back to at a later date, and these details will greatly assist our Technical Support staff in determining the
problem should you need assistance.
Many of the problems that affect motion control systems can be traced to electrical noise, controller software errors, or
mistake in wiring.
Problem Symptoms and Possible Causes
Trouble Solution Measures
Motor is not rotating
No power, to start power supply
Pulse/revolution setting is wrong
DIP switch current setting is wrong
Fault condition exists or the drive is disabled
Motor rotates in the wrong
direction
Motor phases may be connected in reverse
Pulse mode may be wrong
Red light blinking
Red light blinks 1 time or always on, try not to connect the motor and restart the
power supply
Red light blinks 2 times, check the power voltage and restart the power supply
Red light blink 4 times, the motor is not connected or has broken circuit.
Erratic motor motion
Current setting is too small, losing steps
Wrong motor connection or has broken circuit in motor coil.
The current of the control signals is not in the range of 7-15mA
Control signals don’t meet the requirements of chapter 10 , check the waveform
of the control signals
Motor stalls or loss steps
Output current of the drive is too small or motor torque is not enough
Acceleration is set too high
Power supply voltage too low
Modify the activated edge value in the PC software or the control signal is
interfered with.
Excessive motor and drive
heating
Inadequate heat sinking / cooling
Automatic current reduction function not being utilized
Reduce output current

EM870S Digital Stepper Drive User Manual
Page | 14
13. Warranty
Twelve Month Warranty
Leadshine Technology Co., Ltd. warrants its products against defects in materials and workmanship for a period of 12
months from shipment out of factory. During the warranty period, Leadshine will either, at its option, repair or replace
products which proved to be defective.
Exclusions
The above warranty does not extend to any product damaged by reasons of improper or inadequate handlings by
customer, improper or inadequate customer wirings, unauthorized modification or misuse, or operation beyond the
electrical specifications of the product and/or operation beyond environmental specifications for the product.
Obtaining Warranty Service
To obtain warranty service, please contact Motion Control Products Ltd. to obtain a returned material authorization
number (RMA) before returning product for service.
Shipping Failed Products
If your product fail during the warranty period, please contact your seller for how and where to ship the failed product
for warranty or repair services first, you can also e-mail customer service at [e-mail] to
obtain a returned material authorization number (RMA) before returning product for service. Please include a written
description of the problem along with contact name and address.