GW Instek PSW User Manual

Multi-Range DC Power Supply

PSW Series

USER MANUAL

GW INSTEK PART NO. 82SW-80400MH1

ISO-9001 CERTIFIED MANUFACTURER

This manual contains proprietary information, which is protected by copyright. All rights are reserved. No part of this manual may be photocopied, reproduced or translated to another language without prior written consent of Good Will company.

The information in this manual was correct at the time of printing. However, Good Will continues to improve products and reserves the rights to change specification, equipment, and maintenance procedures at any time without notice.

Good Will Instrument Co., Ltd.

No. 7-1, Jhongsing Rd., Tucheng Dist., New Taipei City 236, Taiwan.

SAFETY INSTRUCTIONS
Table of Contents
SAFETY INSTRUCTIONS ...................................................	5
GETTING STARTED ...........................................................	9
PSW Series Overview ...........................	10
Appearance ..........................................	15
Theory of Operation .............................	22
OPERATION ....................................................................	35
Set Up..................................................	37
Basic Operation ...................................	57
Parallel / Series Operation ...................	72
Test Scripts ..........................................	87
CONFIGURATION ...........................................................	96
Configuration .......................................	97
ANALOG CONTROL .......................................................	116
Analog Remote Control Overview .......	117
Remote Monitoring ............................	133
COMMUNICATION INTERFACE .....................................	138
Interface Configuration ......................	139
MAINTENANCE .............................................................	154
FAQ ...............................................................................	156
APPENDIX .....................................................................	158
PSW Default Settings .........................	158
Error Messages & Messages ..............	161
	3

	Table of Contents
LED Display Format ...........................	161
PSW Specifications ............................	162
PSW Dimensions ...............................	177
Declaration of Conformity ..................	182
INDEX............................................................................	183

4

SAFETY INSTRUCTIONS

SAFETY INSTRUCTIONS

This chapter contains important safety instructions that you must follow during operation and storage. Read the following before any operation to insure your safety and to keep the instrument in the best possible condition.

Safety Symbols

These safety symbols may appear in this manual or on the instrument.

Warning: Identifies conditions or practices that

	WARNING	could result in injury or loss of life.
	CAUTION	Caution: Identifies conditions or practices that
		could result in damage to the PSW or to other
		properties.
		DANGER High Voltage
		Attention Refer to the Manual
		Protective Conductor Terminal
		Earth (ground) Terminal

5

PSW Series User Manual

Do not dispose electronic equipment as unsorted municipal waste. Please use a separate collection facility or contact the supplier from which this instrument was purchased.

Safety Guidelines

General

Guideline

CAUTION

Do not place any heavy object on the PSW.

Avoid severe impact or rough handling that leads to damaging the PSW.

Do not discharge static electricity to the PSW.

Use only mating connectors, not bare wires, for the terminals.

Do not block the cooling fan opening.

Do not disassemble the PSW unless you are qualified.

(Measurement categories) EN 61010-1:2010 and EN 61010-2-030 specify the measurement categories and their requirements as follows. The PSW falls under category II.

Measurement category IV is for measurement performed at the source of low-voltage installation.

Measurement category III is for measurement performed in the building installation.

Measurement category II is for measurement performed on the circuits directly connected to the low voltage installation.

0 is for measurements performed on circuits not directly connected to Mains.

	Power Supply		AC Input voltage range: 85VAC~265VAC
	WARNING		Frequency: 47Hz~63Hz
			To avoid electrical shock connect the protective
			grounding conductor of the AC power cord to
			an earth ground.

6

			SAFETY INSTRUCTIONS
	Cleaning the PSW		Disconnect the power cord before cleaning.
			Use a soft cloth dampened in a solution of mild
			detergent and water. Do not spray any liquid.
			Do not use chemicals containing harsh material
			such as benzene, toluene, xylene, and acetone.
	Operation		Location: Indoor, no direct sunlight, dust free,
	Environment		almost non-conductive pollution (Note below)
			Relative Humidity: 20%~ 85%
			Altitude: < 2000m
			Temperature: 0°C to 50°C
		(Pollution Degree) EN 61010-1:2010 and EN 61010-2-030 specify the
		pollution degrees and their requirements as follows. The PSW falls
		under degree 2.
		Pollution refers to “addition of foreign matter, solid, liquid, or
		gaseous (ionized gases), that may produce a reduction of dielectric
		strength or surface resistivity”.
			Pollution degree 1: No pollution or only dry, non-conductive
			pollution occurs. The pollution has no influence.
			Pollution degree 2: Normally only non-conductive pollution
			occurs. Occasionally, however, a temporary conductivity caused
			by condensation must be expected.
			Pollution degree 3: Conductive pollution occurs, or dry, non-
			conductive pollution occurs which becomes conductive due to
			condensation which is expected. In such conditions, equipment
			is normally protected against exposure to direct sunlight,
			precipitation, and full wind pressure, but neither temperature
			nor humidity is controlled.
	Storage		Location: Indoor
	environment		Temperature: -25°C to 70°C
			Relative Humidity: <90%, no condensation
	Disposal	Do not dispose this instrument as unsorted
		municipal waste. Please use a separate collection
		facility or contact the supplier from which this
		instrument was purchased. Please make sure

discarded electrical waste is properly recycled to reduce environmental impact.

7

Earth Neutral Live (Phase)

PSW Series User Manual

Power cord for the United Kingdom

When using the power supply in the United Kingdom, make sure the power cord meets the following safety instructions.

NOTE: This lead/appliance must only be wired by competent persons

WARNING: THIS APPLIANCE MUST BE EARTHED

IMPORTANT: The wires in this lead are coloured in accordance with the following code:

Green/ Yellow: Blue:

Brown:

As the colours of the wires in main leads may not correspond with the coloured marking identified in your plug/appliance, proceed as follows:

The wire which is coloured Green & Yellow must be connected to the Earth terminal marked with either the letter E, the earth symbol or coloured Green/Green & Yellow.

The wire which is coloured Blue must be connected to the terminal which is marked with the letter N or coloured Blue or Black.

The wire which is coloured Brown must be connected to the terminal marked with the letter L or P or coloured Brown or Red.

If in doubt, consult the instructions provided with the equipment or contact the supplier.

This cable/appliance should be protected by a suitably rated and approved HBC mains fuse: refer to the rating information on the equipment and/or user instructions for details. As a guide, a cable of 0.75mm2 should be protected by a 3A or 5A fuse. Larger conductors would normally require 13A types, depending on the connection method used.

Any exposed wiring from a cable, plug or connection that is engaged in a live socket is extremely hazardous. If a cable or plug is deemed hazardous, turn off the mains power and remove the cable, any fuses and fuse assemblies. All hazardous wiring must be immediately destroyed and replaced in accordance to the above standard.

8

GETTING STARTED

GETTING STARTED

This chapter describes the power supply in a nutshell, including its main features and front / rear panel introduction. After going through the overview, please read the theory of operation to become familiar with the operating modes, protection modes and other safety considerations.

PSW Series Overview.......................................................	10
Series lineup ..............................................................................................................	10
Main Features ...........................................................................................................	11
Accessories................................................................................................................	12
PSW 30/80/160 Accessories....................................................................	12
PSW 250/800 Accessories ........................................................................	13
Appearance .....................................................................	15
PSW Front Panel .....................................................................................................	15
Rear Panel .................................................................................................................	18

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PSW Series User Manual

PSW Series Overview

Series lineup

The PSW series consists of 15 models, divided into 3 different model types covering 3 power capacities: Type I (360 Watt), Type II (720 Watt) and Type III (1080 Watt).

Note

Model name

Throughout the user manual, PSW 30, PSW 80, PSW 160, PSW 250 or PSW 800 will refer to any of the PSW models with a maximum voltage rating of 30V, 80V, 160V, 250V or 800V, respectively.

Type

Voltage Rating

Current Rating

Power

PSW 30-36	Type I	0~30V	0~36A	360W
PSW 80-13.5	Type I	0~80V	0~13.5A	360W
PSW 160-7.2	Type I	0~160V	0~7.2A	360W
PSW 250-4.5	Type I	0~250V	0~4.5A	360W
PSW 800-1.44	Type I	0~800V	0~1.44A	360W
PSW 30-72	Type II	0~30V	0~72A	720W
PSW 80-27	Type II	0~80V	0~27A	720W
PSW 160-14.4	Type II	0~160V	0~14.4A	720W
PSW 250-9	Type II	0~250V	0~9A	720W
PSW 800-2.88	Type II	0~800V	0~2.88A	720W
PSW 30-108	Type III	0~30V	0~108A	1080W
PSW 80-40.5	Type III	0~80V	0~40.5A	1080W
PSW 160-21.6	Type III	0~160V	0~21.6A	1080W
PSW 250-13.5	Type III	0~250V	0~13.5A	1080W
PSW 800-4.32	Type III	0~800V	0~4.32A	1080W

10

GETTING STARTED

Apart from the differences in output, each unit differs in size. The 720 and 1080 watt models are larger than the 360 watt models to accommodate the increase in power.

360 Watt models				720 Watt models				1080 Watt models
Type I				Type II				Type III
	Multi-Range DC Power Supply Voltage				Multi-Range DC Power Supply Voltage				Multi-Range DC Power Supply Voltage
PSW 30-36			360W	PSW 30-72			720W	PSW 30-108			1080W
VSR			W	VSR			W	VSR			W
C V			V	C V			V	C V			V
RMT				RMT				RMT
ALM 20	40 60 80	100	%W	ALM 20	40 60 80	100	%W	ALM 20	40 60 80	100	%W
DLY			Current	DLY			Current	DLY			Current
C C			W	C C			W	C C			W
ISR			A	ISR			A	ISR			A
Function	OVP/OCP	Set	Output	Function	OVP/OCP	Set	Output	Function	OVP/OCP	Set	Output
Test	Lock/Local PWR DSPL			Test	Lock/Local PWR DSPL			Test	Lock/Local PWR DSPL

Main Features

Performance	High performance/power
	Power efficient switching type power supply
	Low impact on load devices
	Fast transient recovery time of 1ms
	Fast output response time
Features	OVP, OCP and OTP protection
	Adjustable voltage and current slew rates
	User adjustable bleeder control to quickly
	dissipate the power after shutdown to safe
	levels.
	Extensive remote monitoring and control
	options
	Support for serial* and parallel connections.
	*(30, 80, 160 volt models only)
	Power on configuration settings.
	Supports test scripts
	Web server monitoring and control

11

		PSW Series User Manual
Interface		Ethernet port
	Analog connector for analog voltage and current
		monitoring
		USB host and device port

Accessories

Please check the contents before using the PSW.

PSW 30/80/160 Accessories

Standard	Part number	Description
Accessories
	CD-ROM	User manual,
		programming manual
	4323-30600101	Power cord (Type I/II)
	4320-91001101	Power cord (Type III)
	1042-SWLV0301	Output terminal cover
	GTL-123	Test leads: 1x red, 1x black
	GTL-240	USB Cable
	PSW-004	Basic Accessory Kit:
		M4 terminal screws and
		washers x2, M8 terminal
		bolts, nuts and washers x2,
		Air filter x1, Analog control
		protection dummy x1,
		Analog control lock level x1
Optional	Part number	Description
Accessories
	GET-001	Extended terminal
	PSW-001	Accessory Kit:
		Pin contact x10, Socket x1,
		Protection cover x1
12

			GETTING STARTED
		PSW-002	Simple IDC
			Tool
		PSW-003	Contact
			Removal Tool
		PSW-005	Series operation cable for 2
			units.
		PSW-006	Parallel operation cable for
			2 units.
		PSW-007	Parallel operation cable for
			3 units.
		GRA-410-J	Rack mount adapter (JIS)
		GRA-410-E	Rack mount adapter (EIA)
		GUG-001	GPIB to USB adapter
		GTL-240	USB Cable
		57RG-30B00201	Large filter (Type II/III)
	Download	Name	Description
		psw_cdc.inf	USB driver
	PSW 250/800 Accessories
	Standard	Part number	Description
	Accessories
		CD-ROM	User manual,
			programming manual
		4323-30600101	Power cord (Type I/II)
		4320-91001101	Power cord (Type III)
		1042-SWHV0301	High voltage output
			terminal cover
		GTL-240	USB Cable
		39BT-50900401	High voltage output
			terminal
			13

			PSW Series User Manual
		PSW-008	Basic Accessory Kit:
			(Air filter x1, Analog control
			protection dummy x1,
			Analog control lock level x1
	Optional	Part number	Description
	Accessories
		GET-002	Extended terminal
		PSW-001	Accessory Kit:
			Pin contact x10, Socket x1,
			Protection cover x1
		PSW-002	Simple IDC
			Tool
		PSW-003	Contact
			Removal Tool
		PSW-006	Parallel operation cable for
			2 units.
		PSW-007	Parallel operation cable for
			3 units.
		GRA-410-J	Rack mount adapter (JIS)
		GRA-410-E	Rack mount adapter (EIA)
		GTL-130	Test leads: 2x red, 2x black
		GUG-001	GPIB to USB adapter
		GTL-240	USB Cable
		57RG-30B00201	Large filter (Type II/III)
	Download	Name	Description
		psw_cdc.inf	USB driver

14

GETTING STARTED

Appearance

PSW Front Panel

720W: PSW 30-72, 80-27, 160-14.4, 250-9, 800-2.88

	PSW 30-72						720W	Voltage	Voltage
				Multi-Range DC Power Supply
Display	C V								knob
	VSR						W
							V
	RMT
	ALM	20	40	60	80	100	%W
	DLY						W	Current	Current
	C C						A
	ISR								knob
Cover
panel	Function		OVP/OCP			Set		Output	Output
	Test		Lock/Local PWR DSPL						key
Power
switch									Function
									keys
									USB A
									port
1080W: PSW 30-108, 80-40.5, 160-21.6,						360W: PSW 30-36,
250-13.5, 800-4.32						80-13.5, 160-7.2,
						250-4.5, 800-1.44

			Multi-Range DC Power Supply Voltage
PSW 30-108						1080W
VSR						W
C V
						V
RMT
ALM	20	40	60	80	100	%W
DLY						Current
C C						W
						A
ISR

			Multi-Range DC Power Supply Voltage
PSW 30-36						360W
VSR						W
C V
						V
RMT
ALM	20	40	60	80	100	%W
DLY						Current
C C						W
						A
ISR

Function OVP/OCP	Set	Output	Function OVP/OCP	Set	Output

Test

Lock/Local PWR DSPL

Test

Lock/Local PWR DSPL

15

PSW Series User Manual

Function Keys

Display

Indicators

16

The Function keys along with the Output key will light up when a key is active.

Function	The Function key is used to
	configure the power supply.
OVP/OCP	Set the over current or over
	voltage protection levels.
Set	Sets the current and voltage limits.
Test	Used to run customized scripts for
	testing.
Lock/Local	Locks or unlocks the panel keys to
	prevent accidentally changing
	panel settings.

PWR DSPL

VSR

C V

RMT

ALM

DLY

C C

ISR

Toggles the display from viewing V/A  V/W or A/W*.

*Press the Voltage knob for V/W, press the Current knob for A/W.

Voltage Slew Rate

Constant Voltage Mode

Remote Control Mode

Alarm on

Delay Output

Constant Current Mode

Current Slew Rate

GETTING STARTED

Voltage Knob

Current Knob

Output

USB

Power Switch

20 40 60

80 100 % W

Voltage

Current

Output

Power bar

Indicates the current power output as a percentage.

Sets the voltage.

Sets the current.

Press to turn on the output. The Output key will light up when the output is active.

USB A port for data transfer, loading test scripts etc.

Used to turn the power on/off.

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PSW Series User Manual

Rear Panel

720W: PSW 30-72, 80-27, 160-14.4
Analog control	Sense+	USB B		Output
connector	terminal	port		terminal
				(+)
Chassis
ground
Sense-		SER.NO. LABEL
terminal
Output
terminal (-)
					Fan
LAN
	LAN
		AC	100	240V
		47	63Hz	1000VA MAX.	AC Input
1080W: PSW 30-108, 80-40.5, 160-21.6			360W: PSW 30-36,
			80-13.5, 160-7.2

AC Input

	SER.NO. LABEL
N	L
LAN
	AC	100	240V
	47	63Hz	1500VA MAX.
18

AC	100	240V
47	63Hz	500VA MAX.
	LAN

GETTING STARTED

720W: PSW 250-9, 800-2.88

Analog control	Sense+	USB B	Output
connector	terminal	port	terminals +V

Sense-
terminal
V	SN.C. S	V		SER.NO. LABEL
Chassis
ground
Output
terminals -V
					Fan
LAN
			LAN	AC 100	240V
				47 63Hz	1000VA MAX.
					AC Input

1080W: PSW 250-13.5, 800-4.32

AC Input

V	SN.C. S	V
	LAN

SER.NO. LABEL

N	L
	AC 100		240V
	47	63Hz	1500VA MAX.

360W: PSW 250-4.5, 800-1.44

V	SN.C. S	V
		AC 100		240V
		47	63Hz	500VA MAX.
			LAN

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	PSW Series User Manual
Analog Control	Standard 26 pin MIL connector
Connector	(OMRON XG4 IDC plug).
	The analog control connector is
	used to monitor current and voltage
	output, machine status (OVP, OCP,
	OTP etc.), and for analog control of
	the current and voltage output.
	Use an OMRON XG5 IDC socket as
	the mating socket.
Output Terminals	Positive (+) and negative (-) output
(30, 80, 160 volt	terminals.
models)
	Chassis ground

Sense (-S) and Sense (+S) terminals.

Output Terminals The 250 and 800 volt models use a 9 pin connector (250, 800 volt and a plug for the output and sense terminal models) connections. The plug is a MC420-38109Z plug by

DECA SwitchLab Inc. This plug is also available separately (GW part number 39BT-50900401).

Positive (V+) and negative (V-)

V

SN.C. S

V

output terminals (3 of each).

Chassis ground

V

SN.C. S

V

											Sense (-S) and Sense (+S)
		V		SN.C.		S	V
											terminals.

20

GETTING STARTED

USB B port

Fans

Ethernet Port

LAN

The USB B port is used for remote control.

Temperature controlled fans

The ethernet port is used for remote control and digital monitoring from a PC.

Line Voltage

Input

(Type I/TypeII)

Line Voltage

Input

(Type III)

Type I: PSW 30-36/80-13.5/

160-7.2/250-4.5, 800-1.44

Type II: PSW 30-72/80-27/

160-14.4/250-9, 800-2.88

Voltage Input: 100~240 VAC

Line frequency: 50Hz/60 Hz (Automatically switchable)

N L	Type III:
	PSW 30-108/80-40.5/160-21.6/
	250-13.5/800-4.32

Voltage Input: 100~240 VAC

Line frequency: 50Hz/60 Hz (Automatically switchable)

21

PSW Series User Manual

Theory of Operation

The theory of operation chapter describes the basic principles of operation, protection modes and important considerations that must be taken into account before use.

Operating Area Description

Background	The PSW power supplies are regulated DC
	power supplies with a high voltage and current
	output. These operate in CC or CV mode
	within a wide operating range limited only by
	the output power.
	The operating area of each power supply is
	determined by the rated output power as well
	as the voltage and current rating. For example
	the operating area and rated power output for
	the PSW 30-36 is shown below.
	Voltage			PSW 30-36 Operating Area
	30
					360W rated power
	10
							Current
	12			36

When the power supply is configured so that the total output (current x voltage output) is less than the rated power output, the power supply functions as a typical constant current, constant voltage power supply.

If however, the power supply is configured such that the total output (current x voltage output) exceeds the rated power output, the

22

GETTING STARTED

effective output is actually limited to the power limit of the unit. In this case the output current and voltage then depend purely on the load value.

Below is a comparison of the operating areas of each power supply.

PSW 800V Series Operating Area

	0.45	0.9	1.35 1.44	2.88			4.32
	900
	800							800
(V)	700					Type I
	600					Type II
Voltage	500
						Type III
	400
	300			30				250
	200
	100			25
	0			15
				…Po…
	0	1		2	3		4	5
				CurrenVolt(A)	120468	0

PSW 250V Series Operating Area

	1.44	2.88	4.32	4.5	9		13.5
	250							250
(V)	200						Type I
							Type II
Voltage
	150						Type III
	100			30				80
	50
				25
	0			15
				…Po…
	0	3		6	9		12	15
				CurrenVolt(A)	120468	0

23

PSW Series User Manual

PSW 160V Series Operating Area

	2.25	4.5	6.75	7.2	14.4			21.6
	180
	160								160
(V)	140						Type I
	120						Type II
Voltage	100
							Type III
	80
	60				30				50
	40
	20				25
	0				15
					…Po…
	0	5			10	15		20	25
					CurrenVolt(A)	120468	0

PSW 80V Series Operating Area

		4.5	9.0	13.5		27			40.5
	90
	80									80
(V)	60							Type I
								Type II
Voltage	40							Type III
						30				26.6
	20
						25
	0					15
						…Po…
	0	5	10	15	20	25	30	35	40	45
					CurrenVolt(A)		120468	0

24

GETTING STARTED

PSW 30V Series Operating Area

	12	24	36		72			108
	35
	30							30
(V)	25						Type I
	20						Type II
Voltage
							Type III
	15
	10			30				10
	5
				25
	0			15
				…Po…
	0	20	40	60		80	100	120
				CurrenVolt(A)	120468	0

CC and CV Mode

CC and CV mode When the power supply is operating in Description constant current mode (CC) a constant current

will be supplied to the load. When in constant current mode the voltage output can vary, whilst the current remains constant. When the load resistance increases to the point where the current limit (ISET) can no longer be sustained the power supply switches to CV mode. The point where the power supply switches modes is the crossover point.

When the power supply is operating in CV mode, a constant voltage will be supplied to the load, whilst the current will vary as the load varies. At the point that the load resistance is too low to maintain a constant voltage, the power supply will switch to CC mode and maintain the set current limit.

The conditions that determine whether the power supply operates in CC or CV mode depends on the set current (ISET), the set voltage

25

PSW Series User Manual

(VSET), the load resistance (RL) and the critical resistance (RC). The critical resistance is

determined by VSET/ISET. The power supply will operate in CV mode when the load resistance is greater than the critical resistance. This means that the voltage output will be equal to the VSET voltage but the current will be less than ISET. If the load resistance is reduced to the point that the current output reaches the ISET level, the power supply switches to CC mode.

Conversely the power supply will operate in CC mode when the load resistance is less than the critical resistance. In CC mode the current

output is equal to ISET and the voltage output is less than VSET.

V
	CV	RL=RC
VSET
		Crossover
RL>RC		point
		CC
	RL<RC
		I
		ISET

26

	GETTING STARTED
Slew Rate
Theory	The PSW has selectable slew rates for CC and
	CV mode. This gives the PSW power supply
	the ability to limit the current/voltage draw of
	the power supply. Slew rate settings are
	divided into High Speed Priority and Slew
	Rate Priority. High Speed Priority mode
	disables slew rate settings for CC or CV mode.
	Slew Rate Priority mode allows for user
	adjustable slew rates for CC or CV mode. The
	rising and falling slew rate can be set
	independently.

Slew rate=
Disabled	Slew rate =
	Enabled

Bleeder Control

Background	The PSW DC power supplies employ a bleed
	resistor in parallel with the output terminals.
	PSW	Bleed	Load
		resistor

Bleed resistors are designed to dissipate the power from the power supply filter capacitors

27

PSW Series User Manual

when power is turned off and the load is disconnected. Without a bleed resistor, power may remain charged on the filter capacitors for some time and be potentially hazardous.

In addition, bleed resistors also allow for smoother voltage regulation of the power supply as the bleed resistor acts as a minimum voltage load.

The bleed resistance can be turned on or off using the configuration settings.

By default the bleed resistance is on. For battery Note charging applications, be sure to turn the bleed resistance off as the bleed resistor can discharge

the connected battery when the unit is off.

Internal Resistance

Background

Internal

Resistance Range

On the PSW, the internal resistance of the power supply can be user-defined in software. (Internal Resistance Setting, page 105). When the internal resistance is set it can be seen as a resistance in series with the positive output terminal. This allows the power supply to simulate power sources that have internal resistances such as lead acid batteries.

Unit Model	Internal Resistance Range
PSW 30-36	0.000	~ 0.833Ω
PSW 30-72	0.000	~ 0.417Ω
PSW 30-108	0.000	~ 0.278Ω
PSW 80-13.5	0.000	~ 5.926Ω
PSW 80-27	0.000	~ 2.963Ω
PSW 80-40.5	0.000	~ 1.975Ω
PSW 160-7.2	0.000	~ 22.222Ω
PSW 160-14.4	0.000	~ 11.111Ω
PSW 160-21.6	0.000	~ 7.407Ω

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	GETTING STARTED
PSW 250-4.5	0.00 ~ 55.55Ω
PSW 250-9	0.00 ~ 27.77Ω
PSW 250-13.5	0.00 ~ 18.51Ω
PSW 800-1.44	0.0 ~ 555.5Ω
PSW 800-2.88	0.0 ~ 277.8Ω
PSW 800-4.32	0.0 ~ 185.1Ω

Alarms

The PSW power supplies have a number of protection features. When one of the protection alarms are set, the ALM icon on the display will be lit. For details on how to set the protection modes, please see page 57.

OVP	Overvoltage protection (OVP) prevents a high
	voltage from damaging the load.
OCP	Overcurrent protection prevents high current
	from damaging the load.
OTP	Over temperature protection protects the
	instrument from overheating.
Power Switch Trip	When the Power Switch Trip configuration
	setting is enabled, the power supply will
	automatically shut down when a protection
	setting has been tripped (OCP, OVP, OTP).
Alarm output	Alarms are output via the analog control
	connector. The alarm output is an isolated
	open-collector photo coupler output.

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PSW Series User Manual

Considerations

The following situations should be taken into consideration when using the power supply.

	Inrush current	When the power supply switch is first turned
		on, an inrush current is generated. Ensure there
		is enough power available for the power
		supply when first turned on, especially if a
		number of units are turned on at the same
		time.
	Caution	Cycling the power on and off quickly can cause the
		inrush current limiting circuit to fail as well as
		reduce the working life of the input fuse and power
		switch.
	Pulsed or Peaked	When the load has current peaks or is pulsed, it
	loads	is possible for the maximum current to exceed
		the mean current value. The PSW power
		supply ammeter only indicates mean current
		values, which means for pulsed current loads,
		the actual current can exceed the indicated
		value. For pulsed loads, the current limit must
		be increased, or a power supply with a greater
		capacity must be chosen. As shown below, a
		pulsed load may exceed the current limit and
		the indicated current on the power supply
		ammeter.

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