Lincoln Electric Computer Weld Technology DMC II User manual

DMC IITM
DC DRIVE MOTOR CONTROL
Operation / Installation Manual
Manual Part Number: S8M5021
April 24, 2019
Computer Weld Technology
A Lincoln Electric Brand
10702 Old Bammel N Houston Rd.
Houston, TX 77086
Phone: (713) 462
-2118
Fax: (713) 462
-2503
Email: [e-mail]

SAFETY PRECAUTIONS – READ BEFORE USING
Welding is not particularly hazardous when certain safety practices are followed. Everyone using this
equipment should be thoroughly trained in safe welding practices. Failure to observe safe practices may cause
serious injury.
Handling welding torches presents no danger if the appropriate safety regulations are strictly adhered to. For
example:
•Starting procedures must be reserved for those fully conversant with processes relating to arc
welding equipment.
•Arc welding can prove damaging to eyes, skin, and hearing! It is therefore imperative that both
management and operators understand and follow the ANSI Standard Z49.1, SAFETY IN
WELDING ANDCUTTING. All Personal Protective Equipment (PPE) shall be in place in
accordance with this referenced specification and all other applicable and governing regulations.
•The operating data provided in the Specifications are maximum values. Overloading the welding
torch will inevitably damage the product and void any and all warranties.
•Before changing any parts on the torch or control box, disconnect the torch from the welding
power source and disconnect the control box input power source. Unplug the control box from the
electrical outlet.
•The operating instructions for all other welding components - e.g. power source, wire feed and
cooling unit must be followed per the manufacturer’s recommendations.
•Never pull the cable assembly across sharp edges or set down on a hot surface.
•Never move the torch by pulling or dragging by the welding torch or cable.
•Curtains or partitions shall be installed to protect other workers or observers from arc radiation.
•When handling gas cylinders, consult the instructions issued by the manufacturers and the
suppliers of the pressurized gas.
•Work pieces that have been degreased using chlorinated solvents must be sprayed down with
clean water before welding starts to avoid the risk of phosgene forming. For the same reason, no
degreasing baths containing chlorine must be placed close to the welding point.
•All vapors given off by metals can cause harm and a special warning is attached to lead,
cadmium, copper, zinc, and beryllium. Take appropriate precautions to ensure that the legal
maximum levels of toxic concentrations are not exceeded.
•Do not touch the welding torch with bare skin until it has had adequate time to cool down.
•Wait to adjust the rotation diameter until the torch has cooled to room temperature.
Fume and Gases
FUMES AND GASES can be hazardous. Welding and cutting
produces fumes and gases. Breathing these fumes and gases
can be hazardous to your health.
•Keep your head out of the fumes. Do not breathe the fumes.
•If inside, ventilate the area and/or use local forced ventilation at the arc to remove welding and
cutting fumes and gases. The recommended way to determine adequate ventilation is to sample
for the composition and quantity of fumes and gases to which personnel are exposed.
•If ventilation is poor, wear an approved air-supplied respirator.
•Read and understand the Safety Data Sheets (SDSs) and the manufacturer’s instructions for
adhesives, coatings, cleaners, consumables, coolants, degreasers, fluxes and metals.
•Work in a confined space only if it is well ventilated, or while wearing an air-supplied respirator.
Always have a trained watch-person nearby. Welding fumes and gases can displace air and
lower the oxygen level causing injury or death. Be sure the breathing air is safe.
•Do not weld or cut in locations near degreasing, cleaning, or spraying operations. The heat and
rays of the arc can react with vapors to form highly toxic and irritating gases.

•Do not weld or cut on coated metals, such as galvanized, lead, or cadmium plated steel, unless
the coating is removed from the weld area, the area is well ventilated, and while wearing an air
supplied respirator. The coatings and any metals containing these elements can give off toxic
fumes if welded.
Arc Rays
ARC RAYS can burn eyes and skin. Arc rays from welding and cutting processes
produce intense visible and invisible (ultraviolet and infrared) rays that can burn eyes
and skin. Sparks fly off from the weld.
•Wear an approved welding helmet fitted with a proper shade of filter lenses to protect your face
and eyes from arc rays and sparks when welding, cutting, or watching (see ANSIZ49.1 and Z87.1
listed in Safety Standards).
•Wear approved safety glasses with side shields under your helmet.
•Use protective screens or barriers to protect others from flash, glare and sparks; warn others not
to watch the arc.
•Wear body protection made from durable, flame resistant material (leather, heavy cotton, wool).
•Body protection includes oil-free clothing such as leather gloves, heavy shirt, cuff less trousers,
high shoes and a cap.
Welding and Cutting
Welding or cutting on closed containers such as tanks, drums or pipes, can cause
them to blow up. Sparks can fly off from the welding or cutting arc. The flying sparks,
hot work piece and hot equipment can cause fires and burns. Accidental contact of
electrode to metal objects can cause sparks, explosion, overheating or fire. Check
and be sure the area is safe before doing any welding or cutting.
•Remove all flammables within 35 ft. (10.7 m) of the welding or cutting arc. If this is not possible,
tightly cover them with approved covers.
•Do not weld or cut where flying sparks can strike flammable material.
•Protect yourself and others from flying sparks and hot metal.
•Be aware that welding sparks and hot materials from welding and cutting can easily go through
small cracks and openings to adjacent areas.
•Watch for fire, and keep a fire extinguisher nearby.
•Be aware that welding or cutting on a ceiling, floor, bulkhead or partition can cause fire on the
hidden side.
•Do not weld or cut on containers that have held combustibles, or on closed containers such as
tanks, drums, or pipes unless they are properly prepared according to AWS F4.1 and AWS A6.0
(see Safety Standards).
•Do not weld or cut where the atmosphere may contain flammable dust, gas, or liquid vapors
(such as gasoline).
•Connect work cable to the work as close to the welding or cutting area as practical to prevent
welding or cutting current from traveling long, possibly unknown paths and causing electric shock,
sparks and fire hazards.
•Do not use welder to thaw frozen pipes.
•Remove stick electrode from holder or cut off welding wire at contact tip when not in use.
•Remove any combustibles, such as a butane lighter or match, from your person before doing any
welding or cutting.
•After completion of work, inspect area to ensure it is free of sparks, glowing embers, and flames.
•Use only correct fuses or circuit breakers. Do not oversize or by-pass them.

•Follow requirements in OSHA 1910.252 (a) (2) (iv) and NFPA 51B for hot work and have a fire
watcher and extinguisher nearby.
•Read and understand the Safety Data Sheets (SDSs) and the manufacturer’s instructions for
adhesives, coatings, cleaners, consumables, coolants, degreasers, fluxes and metals.
Electric Shock
Touching live electrical parts can cause fatal shocks or severe burns. The electrode
and work circuit is electrically live whenever the output is on. The input power circuit
and machine internal circuits are also live when power is on. In gas metal arc welding
(GMAW), the wire, wire reel, drive roll housing and all metal parts touching the
welding wire are electrically live. Incorrectly installed or improperly grounded
equipment is a hazard.
•Do not use AC output in damp areas, if movement is confined, or if there is danger of falling.
•Use AC output ONLY if required for the welding or cutting process.
•If AC output is required; use remote output control if present on unit. Additional safety
precautions are required when any of the following electrically hazardous conditions are present:
in damp locations or while wearing wet clothing; on metal structures such as floors, gratings or
scaffolds; when in cramped positions such as sitting, kneeling or lying; or when there is a high
risk of unavoidable or accidental contact with the workpiece or ground. For these conditions, use
the following equipment in order presented: 1) a GMAW DC constant voltage (wire) welder, 2) a
DC manual (stick) welder or 3) an AC welder with reduced open circuit voltage. In most
situations, use of a DC, constant voltage wire welder is recommended. And, do not work alone!
•Disconnect input power or stop engine before installing or servicing equipment. Lockout/tagout
input power according to OSHA 29 CFR 1910.147 (see Safety Standards).
•Properly install, ground, and operate this equipment according to its Owner’s Manual and
national, state/provincial and local codes.
•Always verify the supply ground – check and be sure that input power cord ground wire is
properly connected to ground terminal in disconnect box or that cord plug is connected to a
properly grounded receptacle outlet.
•When making input connections attach proper grounding conductor first and double-check
connections.
•Keep cords dry, free of oil and greases and protected from hot metal and sparks.
•Frequently inspect power cord for damage or bare wiring. Replace cord immediately if damaged.
Bare wiring can kill.
•Turn off all equipment when not in use.
•Do not use worn, damaged, undersized or poorly spliced cables.
•Do not drape cables over your body.
•If earth grounding of the workpiece is required; ground it directly with a separate cable.
•Do not touch electrode if you are in contact with the work, ground or another electrode from a
different machine.
•Do not touch electrode holders connected to two welding machines at the same time since
double open circuit voltage will be present.
•Use only well-maintained equipment. Repair or replace damaged parts at once. Maintain unit
according to manual.
•Wear a safety harness if working above floor level.
•Keep all panels and covers securely in place.
•Clamp work cable with good metal-to-metal contact to workpiece or worktable as near the weld
as practical.
•Insulate work clamp when not connected to workpiece to prevent contact with any metal object.
•Do not connect more than one electrode or work cable to any single weld output terminal.
Disconnect cable for process when not in use.

Cylinders
Compressed gas cylinders contain gas under high pressure. If damaged, a cylinder
can explode. Since gas cylinders are normally part of the welding process, be sure to
treat them carefully.
•Protect compressed gas cylinders from excessive heat, mechanical shocks, physical damage,
slag, open flames, sparks and arcs.
•Install cylinders in an upright position by securing to a stationary support or cylinder rack to
prevent falling or tipping.
•Keep cylinders away from any welding, cutting or other electrical circuits.
•Never drape a welding electrode or cutting torch over a gas cylinder.
•Never allow a welding electrode or cutting torch to touch any cylinder.
•Never weld on a pressurized cylinder – explosion will result.
•Use only the correct compressed gas cylinders, regulators, hoses and fittings designed for the
specific application; maintain them and associated parts in good condition.
•Turn face away from valve outlet when opening cylinder valve. Do not stand in front of or behind
the regulator when opening the valve.
•Keep protective cap in place over valve except when cylinder is in use or connected for use.
•Use the right equipment, correct procedures and sufficient number of persons to lift and move
cylinders.
•Read and follow instructions on compressed gas cylinders, associated equipment, and
Compressed Gas Association (CGA) publication P-1 listed in Safety Standards.

Additional Safety Warnings for Installation, Operation and Maintenance
READ INSTRUCTIONS
•Read and follow all labels and the Owner’s Manual carefully before
installing, operating, or servicing the unit.
•Read the safety information at the beginning of the manual and each section.
•Use only genuine replacement parts from the manufacturer.
•Perform maintenance and service according to the Owner’s Manual,
industry standards and national, state/provincial and local codes.
ELECTRIC AND MAGNETIC FIELDS (EMF) can affect implanted Medical Devices
•Wearers of Pacemakers and other Implanted Medical Devices should keep
away.
•Implanted Medical Device wearers should consult their doctor and the device
manufacturer before going near arc welding, spot welding, gouging, plasma arc cutting
or induction.
H.F. RADIATION can cause interference
•High-frequency (H.F.) can interfere with radio navigation, safety services,
computers and communications equipment.
•Have only qualified persons familiar with electronic equipment perform this
installation. The user is responsible for having a qualified electrician promptly correct
any interference problem resulting from the installation.
•Have the installation regularly checked and maintained.
•If notified by the FCC about interference, stop using the equipment at once.
•Keep high-frequency source doors and panels tightly shut, keep spark gaps at correct setting and
use grounding and shielding to minimize the possibility of interference.
California Proposition 65 Warnings
Welding or cutting equipment produces fumes or gases that contain chemicals known to the State of California
to cause birth defects and in some cases, cancer. (California Health & Safety Code Section 25249.5 et seq.)
This product contains chemicals known to the State of California to cause cancer and birth defects or other
reproductive harm. Wash your hands after using.
EMF Information
Electric current flowing through any conductor causes localized electric and magnetic fields (EMF). The current
from arc welding (and allied processes including spot welding, gouging, plasma arc cutting, and induction
heating operations) creates an EMF field around the welding circuit. EMF fields may interfere with some medical
implants, e.g. Pacemakers. Protective measures for persons wearing medical implants have to be taken. For
example, restrict access for passersby or conduct individual risk assessment for welders. All welders should use
the following procedures in order to minimize exposure to EMF fields from the welding circuit:
1. Keep cables close together by twisting or taping them, or using a cable cover.
2. Do not place your body between welding cables. Arrange cables to one side and away from the
operator.
3. Do not coil or drape cables around your body.
4. Keep head and trunk as far away from the equipment in the welding circuit as possible.
5. Connect work clamp to workpiece as close to the weld as possible.
6. Do not work next to, sit or lean on the welding power source.
7. Do not weld while carrying the welding power source wire feeder.

About Implanted Medical Devices:
Implanted Medical Device wearers should consult their doctor and the device manufacturer before performing
or going near arc welding, spot welding, gouging, plasma arc cutting, or induction heating operations. If cleared
by your doctor, then following the above procedures is recommended.
Safety Standards
•ANSI Standard Z49.1, SAFETY IN WELDING AND CUTTING, American Welding Society, 2501
N.W. 7th St., Miami, FL 33125. Free download at http://www.aws.org/technical/AWS_Z49.pdf
•ANSI Standard Z41.1, STANDARD FOR MEN’S SAFETY - TOE FOOTWEAR obtainable from
the American National Standards Institute, 1430 Broadway, New York, NY 10018.
•ANSI Standard Z49.2, FIRE PREVENTION IN THE USE OF CUTTING AND WELDING
PROCESSES obtainable from the American National Standards Institute, 1430 Broadway, New
York, NY 10018.
•OSHA, SAFETY AND HEALTH STANDARDS, 29CRF 1910, obtainable from the U.S.
Government Printing Office, Washington, D.C. 20402.
•OSHA, PERSONAL PROTECTIVE EQUIPMENT, OSH 3151-12R 2003. Free download at
https://www.osha.gov/Publications/osha3151.pdf

Table of Contents
1.0 GENERAL DESCRIPTION ............................................................................................ 1
1.0 FUNCTIONAL DESCRIPTION....................................................................................................................1
2.0 INSTALLATION.............................................................................................................. 3
2.1 LOCATION....................................................................................................................................................3
3.0 OPERATION................................................................................................................... 7
3.1 THEORY OF OPERATION .........................................................................................................................7
3.2 CONTROL CALIBRATION ..........................................................................................................................7
4.0 MODBUS MEMORY MAP ............................................................................................. 9
4.1 GENERAL DESCRIPTION..........................................................................................................................9
4.2 SUPPORTED MODBUS COMMANDS......................................................................................................9
4.3 MEMORY MAP FOR COILS (MODBUS COMMAND 01,05,15)..............................................................9
4.4 COIL DEFINITIONS AND OPERATION.................................................................................................. 10
4.5 MEMORY MAP FOR HOLDING REGISTER (MODBUS COMMAND 03, 06, 16) .............................. 10
4.6 HOLDING REGISTER AND OPERATION.............................................................................................. 10
4.7 MEMORY MAP FOR SLAVE ID (MODBUS COMMAND 17)................................................................ 11
APPENDIX A SYSTEM DRAWINGS ................................................................................. 12
A.1 DMC II LOW VOLTAGE ENCLOSURE ASSEMBLY 110VAC - P/N: S3A5160................................... 12
A.2 DMC II LOW VOLTAGE ENCLOSURE ASSEMBLY 220VAC - P/N: S3A5169................................... 14
A.3 DMC II HIGH VOLTAGE ENCLOSURE ASSEMBLY 110VAC - P/N: S3A5161 .................................. 16
A.4 MILLER A1D4 MOTOR CONTROL CABLE – P/N: S3W5059 .............................................................. 18
A.5 STANDARD W/O TACH MOTOR CONTROL CABLE – P/N: S3W5060 ............................................. 19
A.6LINCOLN NA5 MOTOR CONTROL CABLE – P/N: S3W5072 ............................................................. 20
A.7 STANDARD W/ TACH MOTOR CONTROL CABLE – P/N: S3W5073 ................................................ 21
A.8 OPEN ENDED REMOTE I/O CABLE – P/N: S3W5219......................................................................... 22
A.9 REMOTE I/O CABLE – P/N: S3W5198 ................................................................................................... 23
A.10 COMMUNICATION DIAGRAMS.............................................................................................................. 24

1
1.0 GENERAL DESCRIPTION
1.0 FUNCTIONAL DESCRIPTION
The DMC II Motor Controller is a PWM motor speed controller using an embedded micro controller to
provide motor speed regulation and torque compensation. There are two version of the DMC II
controller. The DMC II-LV has a 24 VDC @ 6.5amps output and the DMC II-HV has a 100 VDC @ 2.8
amps output. The DMC II-LV controller can be used to control 24 volt permanent magnet (PM) motors
up to 150 watts. The DMC II-HV can be used to control 90 Volt permanent magnet motors up to 250
watts. The DMC II is designed to be used with the CWT Weld Sequence Controllers or a user supplied
controller. The DMC II also provides a RS-485 serial port configured to support Modbus RTU protocol.
This port can be used to Operate and configure various features of the DMC II.
The DMC II is used to control linear DC drive motors for wire feed and or travel speed functions. The
DMC II provides speed and torque regulation using an optical encoder or phase sampled Back EMF.
The embedded controller provides precise motor braking and anti-plugging features to extend motor
life.
1.1 Remote I/O Control
The DMC II provides remote speed control using a 0-10 VDC input signal. Two 24 VDC inputs provide
remote direction control. The control provides an optional isolated encoder output signal. A remote I/O
connector located on the rear of the enclosure provides all user control connections.
1.2 Motor Output
The standard DMC II can be used with 24 VDC permanent magnet motors up to 150 watts. The DMC
II HV can be used with 90 VDC permanent magnet motors up to 250 watts. A motor connector located
on the rear of the enclosure provides all user motor connections. The control can be used with or
without an optical tachometer. The control uses a 100 line optical tachometer input and can provide a
5 VDC or 15 VDC output for the tachometer. The tachometer input mode is automatically enabled
when an encoder signal is active. If the encoder is not used the control will switch to the back EMF
sample mode for speed regulation.
1.3 Operational Status
The operational status of the DMC II is displayed using 9 LED’s located on the front panel. The
following is a description of the LED functions:
•READY – Indicates when the controller is ready to respond to input commands
•DRIVE ON – Illuminates when the Motor drive output is active.
•TORGUE – Illuminates when the motor controller detects max current output.
•I/O POWER – Illuminates when power is applied to the isolated I/O.
•FWD/CW – Illuminates when the control has a FWD/CW input applied to the remote I/O.
•REV/CCW - Illuminates when the control has a REV/CCW input applied to the remote I/O.

2
•NET PWR – Illuminates when power is applied to the isolate RS-485 serial Com port.
•+3.8V – Illuminates when the 3.6 volt power supply is active.
•+12V – Illuminates when the +12 volt power supply is active
•+36V – Illuminates when the main motor power supply is active.
1.4 Control Specification
The following are the electrical specifications for the DMC II - HV™:
Power Input
120 vac ± 10% @ 5amps
Armature Current
0.5 – 3.0 amps
Armature Voltage
0 – 100 vdc
Field Voltage
110 vdc nominal
Encoder Input
5 or 15 vdc 100 lines/rev max frequency 25.0khz
Forward Input
24 vdc @ 20ma (Active High)
Reverse Input
24 vdc @ 20ma (Active High)
Speed Reference Input
0-10 vdc @ 0.1 ma
The following are the electrical specifications for the DMC II - LV™:
Power Input
120 vac ± 10% @ 2.5amps
Armature Current
0.5 – 6.5 amps
Armature Voltage
0 – 24 vdc
Encoder Input
5 or 15 vdc 100 lines/rev max frequency 25.0khz
Forward Input
24 vdc @ 20ma (Active High)
Reverse Input
24 vdc @ 20ma (Active High)
Speed Reference Input
0-10 vdc @ 0.1 ma
The following are the mechanical specifications for the DMC II control:
Dimension
4.75"h x 2.0"w x 11.0"l (120.6mm x 50.8mm x 279.4mm)
Mounting Dimension
1.25" wide x 10.25" long, four 0.25” diameter hole
Weight
5 lbs (2.27 kgms)
Operating Temperature
-10°F (-23°C) to +140°F (+60°c)

3
2.0 INSTALLATION
2.1 LOCATION
The DMC II controller should be located near the drive motor it is controlling. The maximum motor
drive cable length is 75 ft. Mount the DMC II controller in a location that allows easy access to the front
and rear panel. Figure 2-1 shows the mounting pattern for the control enclosure.
FIG 2-1: Enclosure Mounting Dimensions
POWER
Computer Weld Technology, Inc.
DMC
I/O PWR TORQUE READY DRIVE ON FWD / CW REV / CCW NET PWR +3.6V +12V +36V
TM
COMMI/O
10.250
0.375
11.000
9.250
0.87
1.250
0.477
2.250
4X Ø0.281
4.750
MOTOR
MAX 6" FOR
CABLE CLEARANCE TOP VIEWSIDE VIEW
FRONT VIEW
REAR VIEW

4
Connect power cable to suitable 115 VAC power outlet. Connect motor control cable to MOTOR
connector on rear of enclosure. Connect remote I/O cable (S3W5219) to I/O connector on rear of
enclosure.
2.1 DC Motor Connector Pin-Out
Several cables are available from the factory, which and can be used for connecting a DC drive motor
to the DMC II™. Consult the factory for available cable assemblies. The following is the pin-out for the
DMC II motor connector:
PIN
DESCRIPTION
A
+15 VDC for optional encoder
B
+5 VDC for optional encoder
C
Not used
D
Not used
E
Not used
F
Chassis Ground
G
Encoder Pulse input ( TTL or 15 Volt Pulse)
H
Encoder Common
J
Motor Field -
K
Motor Armature -
L
Motor Field +
M
Motor Armature +
Figure 2-2: Motor Connector Pin-out
2.2 Optional Encoder Connections
The DMC II can use a 5-volt or 15-volt encoder. Both power outputs are provided on the connector.
Connect the optional motor encoder to the correct voltage output. Use Pin A for a 15-volt encoder or
Pin B for a 5-volt encoder. The DMC II is designed for a 100-line encoder and can be used for motor
speeds up to 3000 rpm. For faster speeds, contact the factory. The following is a typical connection for
a 5-volt TTL encoder:
ENC +5VDC
ENC PULSE 5 volt TTL Encoder
ENC COM
Fig 2-3 5-volt TTL encoder connection
A
B
C
D
E
F
G
H
J
K
L
M

5
The following is the connection diagram for a 15 VDC encoder:
ENC +15VDC
ENC PULSE 15 volt Encoder
ENC COM
Fig 2-4 15-volt TTL encoder connection
2.4 Motor Connection
The DMC-HV can be used with a permanent magnet, or shunt field motors with an armature rating of
90 – 100 volt dc. The DMC II-LV can be used with a permanent magnet motors with an armature rating
of 10 – 24 volt dc. The following is the connection diagram for a permanent magnet motor:
ARM-
ARM+
Fig 2-4 Permanent magnetic motor wiring
A
B
C
D
E
F
G
H
J
K
L
M
A
B
C
D
E
F
G
H
J
K
L
M

6
2.5 Remote I/O Connector Pin-Out
The DMC II is controlled via the REMOTE I/O connector. The control has two (2) 24 VDC inputs for
motor direction control, a 0-10 vdc input for speed control and a 24 VDC output. The following is the
pin-out for the REMOTE I/O connector:
PIN
FUNCTIONAL DEPWMIPTION
1
+24 vdc output @ 100ma output
2
24 vdc common
3
Speed Input signal common
4
Speed input signal ( 0 – 10 vdc)
5
Drive Forward command input (24 vdc @ 10 ma)
6
Drive Reverse command input (24 vdc @ 10 ma)
7
Motor Tachometer output (24 vdc)
8
Frame ground (Cable Shield connection)
Fig 2-6 Remote I/O connector pin-out
A remote I/O cable S3W5058 is available for interfacing the DMC II to the CWT controller or for direct
interface to user supplied PLC controller. The following is an example of using the DMC II controller
with a user supplied PLC controller:
FWD REV
SPEED SIGNAL COM
SPEED SIGNAL (0 – 10 vdc)
Fig 2-7 PLC interface to DMC II™
1
2
3
4
5
6
7
8

7
3.0 OPERATION
3.1 Theory of Operation
The DMC II is PWM motor speed controller. The control uses an embedded micro-controller to
provide line synchronization, phased back EMF sampling and direction control logic with anti-plug
motor reversing. The phased EMF sample provides precise back EMF sample for improve motor
speed regulation. The Anti-plug feature prevents reversing the drive before the motor armature
has stopped. This prevents excessive motor current and brush arcing in the motor.
The Micro-Controller synchronizes all input commands to the incoming line frequency and
assures proper phase angle firing of the power PWM devices. The Analog speed signal is
coupled to a Voltage-to-Frequency convert and is electrically isolated from the off-line control.
The remote direction control inputs are optically coupled to the controller. An isolated 12-vdc-
power supply is provided for all remote input control functions. The user can use this supply to
operate remote input relays or switches for direction control. The supply has a solid-state circuit
breaker, which protects the 12-volt I/O control from external shorts. The circuit breaker will reset
when the 115-vac power is cycled off.
Optional optical tach input is provided which can be used with a 5 or 12 VDC 60-line encoder.
The encoder input is also provided as an output on the remote I/O connector. This output is an
isolated 24-vdc pulse representing the encoder input. When an encoder is installed on the motor
shaft, the DMC II can be set for encoder feedback by installing a jumper on JP3. When the
jumper is installed, the controller uses the tachometer to regulate motor speed. When the jumper
is removed, the controller will use the motor back EMF for speed regulation.
3.2 Control Calibration
The DMC II controller is factory calibrated to produce 2300 rpm with an input of 10 volts. This is
performed using a 100 line Tach and a permanent magnet 1/8 motor. No adjustment is required
to operate different drive motors. However, there may be a need to check or recalibrate the DMC
II for use with a different motor or motor speed range. To calibrate the DMC II perform the
following steps:
Warning - The DMC II is a direct off-line controller. Do not use grounded instruments
during calibration. 115 VAC is exposed on the heat sinks used on the PC Board. Only
qualified personal should perform test or calibrations on the control.
1) Remove the cover from the DMC II controller. Connect a calibrated digital voltmeter to
the speed reference signal on JP1-3 (-) and JP1-4 (+).
2) If encoder is installed on the drive motor connect a frequency counter to the encoder
output JP1-7(+) and JP1-2(-). A 60-line tachometer will produce a direct readout of motor
RPM. If a tach is not installed, use a hand tach to measure actual motor RPM.
3) Connect the DMC II to a suitable 115vac source. Make sure that the motor is free to
rotate then power up the DMC II control.
4) Set the speed reference to 10.0 volts and adjust R4 (MAX) for 2300 (HZ or RPM) or
desired motor speed. When using a Tachometer the maximum motor speed is 3000
RPM.

8
5) Disable the forward direction input. Turn the power off and reinstall the DMC cover.

9
4.0 MODBUS MEMORY MAP
4.1 General Description
This document provides the basic Modbus memory map and command structure for the DMC II
RS-485 communications port. The DMC II supports the Modbus Protocol as specified in the
Modicon Technical publications “Modbus Protocol” (intr7.html). The DMC II control does not
support the Broadcast mode. The controller provides the slave side communications routines for
the RTU mode. The user must define the Slave ID to a unique ID number from 1 – 247. Default
Baud rate is 19.2 K baud - No Parity, One Stop bit. The default factory Device ID is set to 1. The
device ID can be modified by the user by modifying the Device ID register. Depending on the
Device ID range the following baud rate will be set. Device ID 1 – 31 the default baud rate is 19.2
K Baud, Device ID 32 – 63 the Baud rate is 115.2 K Baud, Device ID 64 – 127 the baud rate is
57.6 K Baud. Device ID 128 – 247 The Baud rate is 19.2 K Baud.
4.2 Supported Modbus Commands
The following ModBus commands are supported:
CODE
DESCRIPTION
ADDRESS RANGE
01
Read Coil Status
0-15
03
Read Holding Registers
0-19
05
Force Single Coil
0-15
06
Preset Single Register
0-19
15
Force Multiple Coils
0-15
16
Preset Multiple Registers
0-19
17
Report Slave ID
5 bytes
4.3 Memory Map for Coils (Modbus Command 01,05,15)
The following is the Coil definitions address 0-31:
COIL
ADDRESS
DESCRIPTION
1
0
INP1 – CW remote I/O input
2
1
INP2 – CCW Remote 1/0 Input
3
2
INP3 – Modbus CW Limit Switch Input
4
3
INP4 – Modbus CCW Limit Switch Input
5
4
Home Drive Input
6
5
Auto sequence Move to Position and Halt Input
7
6
Auto sequence Move Length and No Halt Input
8
7
Disable Remote I/O inputs
9
8
DMC II Ready Output (1=Ready, 0=Not Ready)
10
9
Motor Drive On ( 1= On)
11
10
Current Limit Output (1=Current Limit Active)
12
11
Auto Execute Complete (1= Auto Execute Complete)
13
12
Auto Routine Active (1 = Auto Execute Active)
14
13
Auto Execute Fault (1= Auto Execute Fault)
15
14
Save Default Configuration Input ( 1=Save)
16
15
Power Up Reset (1 = Power Up Reset has Occurred)

10
4.4 Coil Definitions and Operation
The DMC II has 16 simulated coils. These coils are used as internal bit flags to perform specific
functions. The DMC II supports both single and group force coil commands. Refer to Section 4.3
for summary of the Coil functions.
4.5 Memory Map for Holding Register (Modbus Command 03, 06, 16)
The following is the Register definitions address 0-19:
REGISTER
ADDRESS
DESCRIPTION
1
0
Motor Speed in steps /msec. (1 - 62535)
2
1
Motor Armature Voltage (1 – 100.0)
3
2
Motor Current (0.0 – 100.0)
4
3
Max Speed Pot Setting (0 – 102.4%)
5
4
Not Used
6
5
Currents position in steps (1 – 62535)
7
6
Not Used
8
7
Move to Position in steps (1 – 62535)
9
8
Calculated Motor RPM ( 1 – 62535 RPM)
10
9
Auto Execute Move Motor Speed
11
10
Auto Execute Home Motor Speed
12
11
Not Used
13
12
Not Used
14
13
LOWSPD:CONFIG MSB = Min Speed: LSB = Enable Auto
Drive Off low speed reference (1 = Enabled)
, Invert Motor
Direction (2 = Invert), Enable Limit Testing in Remote mode
(4=Limits Enabled) , Invert Encoder Direction (8 = Encoder
Inverted) ,Disable User I/O (16 = I/O disabled),
Invert Limit
Switch Inputs (32 = Limits Inverted). Note: CONFIG LSB is a
bit defined input only Bits 0-5 are defined
15
14
Encoder Scale in PPR used to calculate Motor RPM
16
15
Node:Iref MSB=DevID(1-247): LSB = Max Motor Amp
17
16
EMF Kd:Kp (DO NOT MODIFY ) WARNING: Changing this
value may result in a catastrophic failure of the controller
18
17
TACK Kd:Kp (DO NOT MODIFY ) WARNING: Changing this
value may result in a catastrophic failure of the controller
19
18
PWMHZ:Accel (DO NOT MODIFY ) WARNING: Changing
this value may result in a catastrophic failure of the
controller
20
19
Max Encoder frequency ( in Hz)
4.6 Holding Register and Operation
The DMC II has 20 Holding Register. These Holding registers are used as unsigned integers to
perform specific control functions. Only 1-4, 6, 8, 10 and 10 of the Holding Registers are used.
Setting the Registers 4, 6,11-12 will not have any effect on the DMC II controller. However, they
are reserved for future expansion. Holding Reg 13 is used a Bit defined register that enables
specific modes or control configuration. Holding Registers 14 – 20 are used to configure the DMC
II control for a specific motor consult factory before modifying these register The DMC II supports
both single and multiple read/write function commands. Refer to Section 4.5 for summary of the
Register functions. Under normal conditions, do not write to Register 14 - 20. WARNING: