Marway mPower 300 Series User manual

mPower™DC Power Supplies
300 Series
Operating Guide and Reference
Mar 2020 : P/N 501046-300-G

© 2020, Marway Power Systems, Inc. All rights reserved.
mPower™, mPower DC™, and mPower 300™ are trademarks of Marway Power Systems, Inc.
All other trademarks are the property of their respective owners.
Global Support Contacts
Web: www.marway.com
Email: [e-mail]
[e-mail]
Phone: [phone] (7am–5pm PST)
ere may be updates to this documentation and the software it describes at:
http://www.marway.com/mpower-dc-power-supplies

Page 3
mPower 300 Series (Rev G)
1General
1.1 Documentation Symbols........................................................ 5
1.2 Product Key............................................................................. 5
1.3 Intended Product Usage ........................................................ 5
1.4 Safety Notices......................................................................... 6
2Physical Overview
2.1 300 Series 1U Views .............................................................. 7
3Control Features Overview
3.1 General Description................................................................ 9
3.2 Control Elements ..................................................................10
3.2.1 The control panel (HMI) ................................................10
3.2.2 Resolution of the displayed values ..............................13
3.2.3 Share bus connector.....................................................13
3.2.4 Sense connector ...........................................................13
3.2.5 Ethernet port ................................................................. 14
3.2.6 USB port ........................................................................ 14
3.2.7 Analog interface ............................................................14
4Installation
4.1 Transport and Storage..........................................................15
4.1.1 Transport........................................................................15
4.1.2 Packaging ......................................................................15
4.1.3 Storage...........................................................................15
4.2 Unpacking and Visual Check ...............................................15
4.3 Installation Preparation ....................................................... 16
4.3.1 Safety considerations before installation .................... 16
4.3.2 Mounting the unit..........................................................16
4.4 300 Series 1U Power Connections ..................................... 17
4.4.1 AC input connections .................................................... 17
4.4.2 DC output connections ................................................. 17
4.4.3 Grounding of the DC output .........................................18
4.5 Remote Sensing Connection ...............................................19
4.6 Share Bus Connection .........................................................20
4.7 Analog Interface Connection ...............................................20
4.8 USB Port Connection............................................................20
4.8.1 Driver installation (Windows)........................................20
4.8.2 Driver installation (Linux, MacOS)................................20
4.8.3 Alternative drivers .........................................................21
4.9 Initial Startup ........................................................................ 21
4.9.1 Initial network setup .....................................................21
5Operation and Application
5.1 Important Notes....................................................................22
5.1.1 Personal safety ..............................................................22
5.1.2 General ..........................................................................22
5.2 Operating Modes ..................................................................22
5.2.1 Voltage regulation .........................................................22
5.2.2 Current regulation .........................................................23
5.2.3 Power regulation ...........................................................23
5.3 Alarm Conditions .................................................................. 24
5.3.1 Available alarm signals ................................................. 24
5.3.2 Power fail ....................................................................... 24
5.3.3 Overtemperature...........................................................25
5.3.4 Overvoltage....................................................................25
5.3.5 Overcurrent....................................................................25
5.3.6 Overpower......................................................................25
5.4 Manual Operation.................................................................26
5.4.1 Switching the unit on ....................................................26
5.4.2 Switching the unit off....................................................26
5.4.3 Conguration in the setup menu .................................26
5.4.4 Adjustment limits .......................................................... 31
5.4.5 Display modes for actual and set values.....................32
5.4.6 Manual adjustment of set values ................................33
5.4.7 The quick menu.............................................................33
5.4.8 Switching the DC output on or off................................34
5.5 Remote Control.....................................................................35
5.5.1 General ..........................................................................35
5.5.2 Control locations ...........................................................35
5.5.3 Remote control via a digital interface..........................35
5.5.4 Remote control via the analog interface .....................36
5.6 Alarms and Monitoring.........................................................42
5.6.1 Denition of terms.........................................................42
5.6.2 Hardware alarm handling.............................................42
5.7 Control Panel Lock ...............................................................44
5.8 Loading and Saving a User Prole.......................................45
5.9 Parallel Operation in Share Bus Mode................................46
5.9.1 Series connection..........................................................48

Page 4
mPower 300 Series (Rev G)
6Service & Maintenance
6.1 Maintenance / Cleaning ......................................................49
6.2 Troubleshooting / Diagnosis / Repair.................................49
6.2.1 Firmware updates .........................................................49
6.3 Calibration (readjustment)...................................................50
6.3.1 Preface...........................................................................50
6.3.2 Preparation....................................................................50
6.3.3 Calibration procedure ...................................................50
7Contact and Support
7.1 General ..................................................................................53
7.2 Contact Options ....................................................................53
8 Model Specications Aappendix
8.1 Approved Operating Conditions...........................................54
8.2 Model Data-Table Footnotes................................................54
8.3 MPW 300-01 : 1U, 1,500 Watt, 100–240 Vac...................55
8.4 MPW 300-11 : 1U, 3,000 Watt, 200–240 Vac .................. 57

Page 5
mPower 300 Series (Rev G)
1 General
1.1 Documentation Symbols
Warning and safety notices as well as general notices in this document are shown in a box with a symbol as follows:
Symbol for a life threatening danger
Symbol for general safety notices (instructions and damage protection bans) or important
information for operation
Symbol for general notices
1.2 Product Key
Decoding of the product description on the label, using an example:
Configurations:
-000 = standard unit
MPW 300 - 0 1 - 0080 - 050 - 000
mPower power supplies
DC auto-ranging series
Max. Output DC Volts
Max. Output DC Amps
Input Power:
0 = 1-phase, 100-240 Vac
1 = 1-phase, 200-240 Vac
Enclosure Type:
1 = Rackmount 1U
1.3 Intended Product Usage
The equipment is intended to be used as a general purpose power supply only as a variable voltage and current source.

Page 6
mPower 300 Series (Rev G)
1.4 Safety Notices
Mortal danger - Hazardous voltage
• This is electrical equipment with some parts operating with dangerous voltage. All exposed compo-
nents which can have live voltage must be covered.
• All work on connections must be carried out under zero voltage (output disconnect), and may only
be performed by qualied and informed persons. Improper actions can cause fatal injury as well as
serious material damage.
• Never touch cables or connectors directly after unplugging from mains supply as the danger of
electric shock remains. Verify there is zero voltage with a handheld meter.
• Never touch the contacts on DC output terminal directly after switching off the DC output, because
there still can dangerous voltage present, sinking more or less slowly depending on the load. There
also can be dangerous potential between negative DC output to GND or positive DC output to GND
due to charged capacitors. Verify there is zero voltage with a handheld meter.
• Always follow 5 safety rules when working with electric devices:
• Disconnect completely.
• Secure against reconnection.
• Verify that the system has zero voltage.
• Carry out earthing and short-circuiting.
• Provide protection from adjacent live parts.
• The equipment must only be used as intended.
• The equipment is only approved for use within the connection limits stated on the product label.
• Do not insert any object, particularly metallic, through the ventilator slots
• Avoid any use of liquids near the equipment. Protect the unit from wet, damp and condensation.
• Do not connect loads, particularly low resistance, to power supplies under power; sparking may
occur which can cause burns as well as damage to the equipment and to the user.
• ESD regulations must be applied when plugging interface cards or modules into the relative slot
• Interface cards or modules may only be attached or removed after the unit is switched off. It’s not
necessary to open the unit.
• Do not connect external power sources with reversed polarity to DC input or outputs. The equip-
ment will be damaged.
• Avoid where possible connecting external power sources to the DC output, and never those that can
generate a higher voltage than the nominal voltage of the unit.
• Never insert a CAT5 cable which is connected to Ethernet into the master-slave socket on the back
of the unit.
• Always congure the various protecting features against overvoltage etc. for sensitive loads to what
the target application requires.

Page 7
mPower 300 Series (Rev G)
A - Power switch D - Share bus and Sense bus connectors
B - Control panel E - DC output
C - Control interfaces (LAN, USB, Analog) F - AC input connector
The brass screw next to the AC connector is a central grounding point for internal use. Do not un-
screw to connect external GND potential here. The device is grounded via the AC cable.
2 Physical Overview
2.1 300 Series 1U Views
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN
Output
Power Input
Cursor Position
Menu
Cursor Position
On
ESC
Enter
35.00A 80.00V
80.00V 120.00A
Remote:USB
CV
C
D
F
A
B
E

Page 8
mPower 300 Series (Rev G)
1.6” 19.7” ≈1.3”
1U sides shown without DC terminal cover. Note that DC outlet dimensions do not include cable bend radius.
1U top shown without DC terminal cover.

Page 9
mPower 300 Series (Rev G)
3 Control Features Overview
3.1 General Description
The mPower DC power supplies are especially suited to test and industrial applications due to their accuracy,
programmability, wide selection of power ranges, and each unit’s advance auto-ranging power delivery.
For remote control using a PC or PLC, the system include as standard both a USB port and an Ethernet port, as well as a
galvanically isolated analog interface. All interfaces are galvanically isolated up to 1500 Vdc.
In addition, these systems include the ability to be used in parallel. Each unit is congured for set values, alarms, etc., and
the built-in Share bus manages the current load sharing. Operating in this way allows up to 10 units to be combined into a
single system with a total power of up to 48 kW.
The block diagram illustrates the main functions inside the power supply, and their relationships.
Share
and Sense
Main
Controller
(DR)
Power
Management
HMI Display
and Controls
(BE)
Communications
(KE)
ETH USBDC AC Analog

Page 10
mPower 300 Series (Rev G)
3.2 Control Elements
3.2.1 The control panel (HMI)
The HMI (Human Machine Interface) consists of a display, two rotary knobs with pushbutton function and six pushbuttons.
Cursor Position
Menu
Cursor Position
On
ESC
Enter
35.00A 80.00V
80.00V 120.00A Remote:USB
CV
2 3 3 4
5
1
Overview of the elements of the control panel
(1) Display
Used for indication of set values, menus, conditions, actual values and status.
(2)
Left hand rotary knob, with pushbutton function
Turn: adjusts various set values which are related to the DC output voltage.
Push: selects the decimal position of a value to be changed (cursor)
(3)
Buttons
Activates the setup menu for various unit settings (see 5.4.3. Conguration in the setup menu)
Navigates through menus, submenus and parameters (direction: up / left) or changes view mode
Navigates through menus, submenus and parameters (direction: down / right) or changes view mode
Submits altered parameters or set values in submenus, as well enters submenus. Can also be used
to acknowledge alarms.
Cancels changes of parameters in the setup menu or leaves submenus
(4)
Right hand rotary knob, with pushbutton function
Turn: adjusts various set values which are related to the DC output current, the DC output power. Also adjusts
parameters in the setup menu.
Push: selects the decimal position of a value to be changed (cursor)
(5)
On/Off button for DC output
Used to toggle the DC output between on and off, also used to acknowledge alarms. The LED indicates the state
of the DC output, no matter if the unit is manually controlled or remotely (LED on = output on).

Page 11
mPower 300 Series (Rev G)
3.2.1.1 Display
The graphic display is divided into a number of areas. In normal operation the left upper half is used to show actual
values and the lower half is used to display status information and set values:
Actual values
U/I or U/P
Regulation mode
Alarms
Set value of voltage Status: control location / panel lock Set value of current or
Set value of power
Actual values area (upper half)
In normal operation the DC output values (large numbers) of voltage and current resp. of power are displayed, depending
on the selected view mode. The display format of values is according to what’s listed in 3.2.2.
Furthermore, the actual regulation mode CV, CC or CP (see 5.2. Operating Modes) is displayed here, as well as alarms
with abbreviations (OT, OVP, OCP, PF, OPP). For details refer to 5.3. Alarm Conditions.
Set values area (lower half, left and right side)
The set values of voltage and current (mode: U/I) resp. of voltage and power (mode: U/P) are displayed here and are
adjustable with the left hand and right hand rotary knobs when operating the system manually. While doing so, the digit to
adjust can be selected by pushing the corresponding rotary knob, in order to move the cursor. The left hand rotary knob is
always assigned to the DC output voltage and related parameters like OVP or U-max, whereas the right hand rotary knobs
is either assigned to the DC output current and related parameters or to the DC output power. In remote control condition,
no matter if analog or digital, the set values given from remote are displayed here.
Logically, the values are increased by clockwise turning and decreased by anti-clockwise turning, unless they are
somehow limited by a maximum value or an adjustment limit (see 5.4.4. Adjustment limits).
General display and settings ranges:
Display Unit Range Description
Actual voltage V 0-125% UNom Actual values of DC output voltage
Set value voltage V 0-102% UNom Set value for limiting the DC output voltage
Actual current A 0.2-125% INom Actual value of DC output current
Set value current A 0-102% INom Set value for limiting the DC output current
Actual power W 0-125% PNom Actual value of output power, P = U * I
Set value power W 0-102% PNom Set value for limiting DC output power
Adjustment limits A, V, W 0-102% Nominal val. U-max, I-min etc., related to the physical units
Protection settings A, V, W 0-110% Nominal val. OVP, OCP etc., related to the physical units

Page 12
mPower 300 Series (Rev G)
Status area (lower half, middle)
This area shows the control location mode (see 5.5.2. Control locations) or another status (see table below). In case
pushbutton is activated while the output is on, the quick menu (see 5.4.7. The quick menu) will be displayed:

This area furthermore displays various status texts:
Display Description
Locked The HMI is locked
Remote The system is under remote control from:
Analog the built-in analog interface
USB the built-in USB port or a plug in interface module
Ethernet the built-in Ethernet/LAN port
Local The system has been locked by the user explicitly against remote control
3.2.1.2 Rotary knobs
As long as the system is in manual operation, the two rotary knobs are used to adjust set values, as well as
setting the parameters in the settings menu. For a detailed description of the individual functions see section 5.4
Manual Operation on page 27.
3.2.1.3 Pushbutton function of the rotary controls
The rotary controls also include pushbutton functionality. When adjusting values, pushing the rotary dial moves the cursor
in sequence as shown:

Page 13
mPower 300 Series (Rev G)
3.2.2 Resolution of the displayed values
In the display, set values can be adjusted in xed increments. The number of decimal places depends on the unit ratings.
The values have 4 or 5 digits, while actual and set values related to the same physical unit always have the same number
of digits.
Adjustment resolution and number of digits of set values in the display:
Voltage,
OVP, U-min, U-max
Current,
OCP, I-min, I-max
Power,
OPP, P-max
Nominal
Digits
Increment Nominal
Digits
Increment Nominal
Digits
Increment
80 V 4 0.01 V 6 A 4 0.001 A 1500 W 4 1 W
200 V 5 0.01 V 10 A / 12 A 5 0.001 A 3000 W 4 1 W
360 V / 500 V 4 0.1 V 15 A / 20 A 5 0.001 A
750 V 4 0.1 V 25 A 5 0.001 A
30 A / 50 A 4 0.01 A
100 A 5 0.01 A
In manual operation, every set value can be set in the increments given above. In this case the
actual output values set by the system will lie within percentage tolerances as shown in the technical
data sheets. These will inuence the actual values.
3.2.3 Share bus connector
The 2-pole Phoenix socket named Share on the back of the unit is
provided for connection to equally named sockets on other mPower
power supplies to achieve a balanced load current distribution during
parallel connection. When multiple units (up to 10 total) are combined
in parallel operation, the Share bus connectors must be wired together
(+ to + and – to – across all units).
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN
3.2.4 Sense connector
Use the Sense connection for constant voltage operation (CV), and
where the adjusted output voltage has to be held constant on the
load, and not on the power supply’s DC output.
In order to compensate for voltage drops along the DC cables to the
load, the Sense input can be connected to the load.
In order to ensure safety, insulation of high voltage models (i.e. those
with a nominal voltage of 500 V or higher, requires using only the two
outer pins of the 4-pole terminal. The inner two pins, marked with NC
(no connect), must remain unconnected.
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN

Page 14
mPower 300 Series (Rev G)
3.2.5 Ethernet port
The Ethernet port on the back of the unit is provided for remote control
and monitoring. The user has basically two options for access:
1. A website (HTTP, port 80) which is accessible in a standard browser
under the IP or the host name given to the unit. This website offers a
conguration page for network parameters, as well as a input box for
SCPI commands.
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN
2. TCP/IP access via a congurable port (except 80 and other reserved ports). The standard port is 5025, default IP
is 192.168.0.2. Via TCP/IP and this port, communication to the system can be established in most of the common
programming languages.
Using the Ethernet port, the system can be controlled by commands from either SCPI or ModBus RTU protocol. The system
will automatically detect the type of message.
The network setup can be done manually using the on-board control panel or by DHCP. The transmission speed is set to
Auto negotiation (using 10MBit/s or 100MBit/s). Duplex mode is always full duplex.
Be aware that when remote control is in operation, no specic port has priority over the others. If more than one interface
(USB, Ethernet, analog) is connected, commands can come from any of them at any time. Therefore, only one interface
should be used at any one time. However, monitoring is always available on any port at any time.
3.2.6 USB port
The USB-B port on the back of the power supply is provided for
connection to a PC for control communication and for rmware
updates. The driver is available as a download and installs as a virtual
COM port. Details for remote control can be found in the Programming
Guide document on our web site.
The power supply can be addressed through the USB port using the
international standard ModBus RTU protocol, or by SCPI language. The
system recognises the message protocol used automatically.
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN
Be aware that when remote control is in operation, no specic port has priority over the others. If more than one interface
(USB, Ethernet, analog) is connected, commands can come from any of them at any time. Therefore, only one interface
should be used at any one time. However, monitoring is always available on any port at any time.
3.2.7 Analog interface
This 15-pin, Sub-D socket on the back of the unit is provided for
remote control via analog and digital signals.
The input voltage range of the set values and the output voltage
range of the monitor values, as well as reference voltage level can
be switched in the settings menu of the system as 0-5 V or 0-10 V, in
each case for 0-100%.
Be aware that when remote control is in operation, no specic port
has priority over the others. If more than one interface (USB, Ethernet,
analog) is connected, commands can come from any of them at any
time. Therefore, only one interface should be used at any one time.
However, monitoring is always available on any port at any time.
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN

Page 15
mPower 300 Series (Rev G)
4 Installation
4.1 Transport and Storage
4.1.1 Transport
• The handles on the front side of the unit are not for carrying!
• Because of its weight, transport by hand should be avoided where possible. If unavoidable then
only the housing should be held and not on the exterior parts (handles, DC output terminal, rotary
knobs).
• Do not transport when switched on or connected!
• When relocating the equipment use of the original packing is recommended
• The unit should always be carried and mounted horizontally
• Use suitable safety clothing, especially safety shoes, when carrying the equipment, as due to its
weight a fall can have serious consequences.
4.1.2 Packaging
It’s recommended to keep the complete transport packaging for the lifetime of the power supply for relocation or return to
the manufacturer for repair.
4.1.3 Storage
In case of long term storage of the equipment, it is recommended to use the original packaging or similar. Storage must
be in dry rooms, if possible in sealed packaging, to avoid corrosion through humidity—especially to internal components.
4.2 Unpacking and Visual Check
After every transport, with or without packaging, or before commissioning, the equipment should be visually inspected for
damage. An obviously damaged unit (e.g. loose parts inside, damage outside) must under no circumstances be put into
service.

Page 16
mPower 300 Series (Rev G)
4.3 Installation Preparation
4.3.1 Safety considerations before installation
Review safety notes in section 1.4. Safety Notices
• When using a 19" rack, rails suitable for the width of the housing and the weight of the unit are to
be used. (see 8. Model Specications Appendix)
• Before connecting to the mains ensure that the connection is as shown on the product label. Over-
voltage on the AC supply can cause equipment damage.
4.3.2 Mounting the unit
• Select the location for the equipment so that the connection to the load is as short as possible.
• Leave sufcient space behind the equipment, minimum 30 cm (1 ft), for ventilation.
• The unit is not stackable.
• Do not put anything with a total weight of more than 1 kg (2.5 lb) on top of the unit.
With all models, mounting brackets are included to mount the unit in a 19” rack. A rackmount installation will usually
mount the power supply on suitable weight-rated rails (not included), and installed in 19” racks or cabinets. The depth
of the power supply and rack, and its weight must be taken into account when selecting rails. The handles on the front
are for sliding in and out of the cabinet. Slots on the mounting brackets of the front panel are for securing the unit to the
rack’s vertical rails to prevent inadvertent movement on the slides.
If the unit will be used in a table top setting, the brackets may be removed, and self-adhesive feet attached to the bottom
of the unit.
Acceptable and unacceptable installation positions relative to a table surface.
CursorPosition
Menu
CursorPosition
On
ESC
Enter
35.00A 80.00V
80.00V 120.00A Remote:USB
CV
CursorPosition
Menu
CursorPosition
On
ESC
Enter
35.00A
80.00V
80.00V 120.00A
Remote:USB
CV

Page 17
mPower 300 Series (Rev G)
4.4 300 Series 1U Power Connections
4.4.1 AC input connections
Mains connection for an mPower 300 series system is done via the included mains cord. In case a different AC wiring is
required, make sure that the other cable has a minimum cross section of 1.5 mm² (AWG 12).
Dimensioning of the DC wiring to the load/consumer has to reect the following:
• The cable cross section should always be specied for at least the maximum input current of the
unit.
• Continuous operation at the approved limit generates heat which must be removed, as well as
voltage loss which depends on cable length and heating. To compensate for these the cable cross
section should be increased and the cable length reduced.
• The unit can be connected to any wall socket or power distribution, as long as it features a safety
contact (GND) and is capable for 16 A.
• When connecting the unit to a power distribution unit, along with other electric devices, it is import-
ant to consider the total power consumption of all devices on the outlet, so that the maximum cur-
rent (power ÷ minimum voltage) does not exceed the denition for the wall socket, the multi-socket
outlet and/or main distribution
• Before plugging in the input plug ensure that the unit is switched off by its mains switch.
The unit is delivered with a 3 wire mains cord (L, N, GND). If the unit is going to be connected to a standard 2-phase or
3-phase supply, following phases are required:
Nominal power Phases Supply type
1.5 kW / 3 kW L1 or L2 or L3, N, GND At least wall socket 16 A
The default input values of all models in this series are: 230 V, 16 A, 50 Hz. It is internally fused with 16 A. The 16 A input
denition is due to the AC input current depending on the higher intake at low AC voltage (for minimum input voltage see
technical specs).Connection to DC loads
4.4.2 DC output connections
• In the case of a unit with a high nominal current and hence a thick and heavy DC connection cable
it is necessary to take account of the weight of the cable and the strain imposed on the DC connec-
tion. Especially when mounted in a 19" cabinet or similar, where the cable hangs on the DC output,
a strain reliever should be used.
• Connection to and operation with transformerless DC-AC inverters (for example solar inverters)
is restricted, because the inverter can shift the potential of negative output (DC-) against GND
(ground), which is generally limited to max. ±400 V DC.
The DC load output is on the rear side of the unit and is not protected by a fuse. The cross section of the connection cable
is determined by the current consumption, cable length and ambient temperature.

Page 18
mPower 300 Series (Rev G)
For cables up to 1.5 m (5 ft) and average ambient temperature up to 50°C (122 °F), we recommend:
up to 10 A: 0.75 mm² (AWG 18) up to 40 A: 6 mm² (AWG 8)
up to 15 A: 1.5 mm² (AWG 14) up to 60 A: 16 mm² (AWG 4)
up to 30 A: 4 mm² (AWG 10) up to 100 A: 25 mm² (AWG 2)
per lead (multi-conductor, insulated, openly suspended). Single cables of, for example, 70 mm² may be replaced by e.g. 2x
35 mm² etc. If the cables are long then the cross section must be increased to avoid voltage loss and overheating.
4.4.2.1 DC terminals
The diagrams below show an overview of the DC terminals from a plan, side, and top view. Both terminals have a 6mm
hole in a nickel plated copper bar. It is recommended that connection of load cables always utilizes exible cables with
ring lugs.
4.4.2.2 Cable lead and plastic cover
A plastic cover for contact protection is included for the DC terminal. It should always be installed.
The connection angle and the required bending radius for the DC cable must be taken into account
when planning the depth of the complete unit, especially when installing in a 19" cabinet or similar.
In case, the plastic DC cover is going to be used, only horizontal lead of the cables is possible.
4.4.3 Grounding of the DC output
Grounding one of the DC output poles is allowed. Doing so can result in a potential shift of the grounded pole against
GND. Because of insulation, there is a max. allowed potential shift of the DC output poles, which also depends on the unit
model. See 8. Model Specications Appendix.

Page 19
mPower 300 Series (Rev G)
The brass screw next to the AC connector is a central grounding point for internal use! Do not un-
screw to connect external GND potential here! The unit is grounded via the AC cable.
4.5 Remote Sensing Connection
In order to compensate, to a certain degree, the voltage loss in a DC cable, the system provides the ability to connect the
remote sensing input Sense to the load. The system recognizes the remote sensing mode automatically, and regulates the
output voltage (only in CV operation) at the load rather than at its own DC output.
In the technical specications (see section 8. Model Specications Appendix) the level of maximum possible
compensation is given. If that is insufcient, the DC output cable cross section must be increased.
Both pins “NC” of the Sense connector must not be wired!
• Remote sensing is only effective during constant voltage operation (CV) and for other regulation
modes the sense input should be disconnected, if possible, because connecting it generally in-
creases the oscillation tendency
• The cross section of the sense cables is noncritical. However, it should be increased with increasing
cable length. Recommendation: for cables up to 5 m (16 ft) use at least 0.5 mm²
• Sense cables should be twisted and laid close to the DC cables to damp oscillation. If necessary,
an additional capacitor should be installed at the load/consumer to eliminate oscillation
• The Sense inputs must be connected with correct polarity to the load, means Sense+ to DC+ of the
load etc., otherwise both systems may be damaged
Share Sense
NC NC
+ - - +
Analog InterfaceUSBLAN
Output
Load

Page 20
mPower 300 Series (Rev G)
4.6 Share Bus Connection
The “Share” connector on the back side is intended to balance the current of multiple units in parallel operation,
especially when using the integrated function generator of the master unit. For further information about this mode of
operation can be found in section 5.9. Parallel Operation in Share Bus Mode .
For the connection of the share bus the following must be paid attention to:
• Connection is only permitted between compatible units (see 3.2.3. Share bus connector for details)
and between a max. of 10 units
• The Share bus is referenced to DC minus output and thus affected by potential shifts. The potential
of the DC minus has to considered when connecting the Share bus to other units!
• When not using one or several units of a system congured with Share bus, because less power
is required for an application, it is recommended to disconnect the not powered units from the
Share bus, because they may have a negative impact on the control signal on the bus due to their
impedance. Disconnection can be done by simply unplugging them from the bus or using bipolar
switches.
4.7 Analog Interface Connection
The 15 pole connector (Type: Sub-D, D-Sub) on the rear side is an analog interface. To connect this to a controlling
hardware (PC, electronic circuit), a standard plug is necessary (not included in the scope of delivery). It is generally
advisable to switch the unit completely off before connecting or disconnecting this connector, but at least the DC output.
The analog interface is galvanically isolated from the unit internally. If not absolutely necessary, you
should never not connect any ground of the analog interface (AGND) to the DC minus output as this
will cancel the galvanic isolation.