Thurlby Thandar Instruments QPX1200 User Manual

QPX1200 Series

PowerFlex DC Power Supplies

INSTRUCTION MANUAL

Table of Contents

Specification 2 EMC 6 Safety 7 Installation 8 Connections 9 Initial Operation 11 Manual Operation 13 Remote Operation 20 Remote Commands 29 Maintenance 33

Note: The latest revisions of this manual, device drivers and software tools can be downloaded from: http://www.tti-test.com/go/qsx

This manual is 48511-1400 Iss 8

General specifications apply for the tem per ature range 5°C to 40°C. Accuracy specifications apply for the temperature range 18°C to 28°C after 1 hour warm-up with no load and calibration at 23°C. Typical specifications are determined by design and are not guaranteed.

OUTPUT SPECIFICATI ONS

Voltage Range: 0V to 60V Current Range: 0.01A to 50A Power Range: Up to 1200W Voltage Setting: Resolution 1mV

Current Setting: Resolution 10mA

Operating Mode: Constant voltage or constant current with automatic cross-over

Specification

Accuracy: 0.1% of setting ± 2mV

Accuracy: 0.3% of setting ± 20mA

provided that the power demanded stays within the power envelope, see graph. Outside of this envelope the output bec om es unregulated. CV, CI or UNREG mode indication in display.

QPX 1200 POWER ENVELOPE

Output Switch: Electronic, with ON indication.

Preset voltage and current displayed when off.

Output T erminals: Front panel safety terminals accepting 6mm wire diameter, 6mm

plugs or 8mm spades at 50 Amps max, or 4mm plugs at 30 Amps max. Duplicate rear panel terminals.

Sensing: Switchable between local and remote. Screwless remote sense

terminals on both front and rear panels. Sense miswiring t r ip and indication.

Ripple & Noise (20MHz bandwidth):

Typically < 3m Vrms, <20mV pk-pk at maximum load, CV mode

Load Regulation: Change in output for any load change within PowerFlex envelope,

using remote sense: Constant voltage: <0.01% ± 5mV

Line Regulation: Change in output for a 10% line change:

Constant voltage: <0.01% ± 5mV

Transient Response: <250us to within 100mV of set level for a 5% to 95% load chang e.

Output Protection: Output will withstand an applied forward voltage of up to 70V.

Reverse protection by diode clamp for reverse currents up t o 3A.

Over-voltage Protection (OVP):

Over-current Pr otection (OCP):

Over-temper at ure Protection: The output will be tripped off if a fault c auses the internal

Temperature Coeff icient : Typically < 100ppm /°C

METER SPECIFICATIONS

Display Ty pe: 5-digit (Volts), 4-digit (Am ps) , black-on-white b a c klit LCD. Voltage (CI Mode and Unreg): Resolution 1mV

Current (CV Mode & Unreg): Resolution 10mA

V x A: Resolution 0·1W

V/A: Meter shows calculated nominal V/A value, t ogether with

Range 2V to 65V. Resolut ion 0.1V; accuracy: 0.2% ± 0.2V. Response time typically 100µs.

Range 2A to 55A. Resolution 0.1A; accuracy: 0.5% ± 0.2A. Response time typically 100ms.

temperature to rise excessively.

Accuracy: 0.1% of reading ± 2 dig its

Accuracy: 0.3% of reading ± 2 dig its

Accuracy: 0·5% ± 0·1W

uncertainty range; 5 digit resolution.

LOGIC CONTROL INPUT and OUTPUT

LOGIC IN is a rear-panel opto-isolated input that is act ivated at an input c ur r ent greater than approximately 1mA. User can set LOGIC IN (via the keyboard) t o enable t he out put, disable the output, or be ignored when it is activated.

LOGIC OUT is an isolated rear-panel open-collector output that will sink up to 2mA when activated (‘switch closure’); the maximum voltage that can be applied to LOGI C O UT is 30VDC. User can set LOGIC OUT to be ‘closed’ or ‘open’ for output enabled or disabled, current limit (CI mode), power limit (UNREG mode), or for any fault trip.

ANALOG REMOTE CONTROL and MONITORING

Non-isolated inputs and outputs to set voltage and current limit and to m onit or actual output voltage and current. These signals are referenced to the positive output and have a range of 0 to 10V or 0 to 5V (selectable via the keyboard).

Analogue Control Accuracy: Voltage: 0.3% ± 4mV; Current: 0.5% ± 40mA Analogue Monitor Accuracy: Voltage: 0.3% ± 4mV; Current: 0.5% ± 40mA

KEYBOARD & ROTARY CONTRO L

All functions, including the selection and set-up of the remote control interfaces, can be set from the keyboard. The rotary Jog control can be used to adjust output voltage and current settings in a quasi-analogue mode.

DISPLAY FEATURES

The display is a 240 x 64 pixel transflective LCD, backlit by white LEDs; contrast is softwarecontrolled and can be adjusted from t he keyboard.

The default status display shows the VOLTS (5 digits) and AMPS (4 digits) in 10mm high characters, plus the present output mode. At other times, for example during store or recall of instrument set-ups, the display shows up to 6 lines of information, instructions, or prompts.

INTERFACES

Full digital remote control facilities are available through the RS232, LAN and USB interfaces. Setting and readback resolutions are t he s am e as the Output and Meter specifications respectively.

RS232: Standard 9-pin D-connector. Baud r at e 9600. USB: Standard USB 2.0 hardware connection. LAN: Ethernet 100/10base-T hardware connection.

GPIB (factory option): Conforming with IEEE488.1 and IEEE488.2.

LXI V1.2, Class C compliant.

Remote Command Processing Time:

GENERAL

AC Input: 110V – 240V AC ± 10%, 50/60Hz.

Power Consumption: 1600VA max. Operating Range: +5ºC to +40ºC, 20% to 80% RH. Storage Range: Environmental: Indoor use at altitudes up to 2000m, Pollution Degree 2. Store/Recall: Up to 10 set-ups can be saved and recalled via the keyboard or

Safety: Complies with EN61010-1. EMC: Complies with EN61326. Size: 130mm H (3U) x 356mm W x 413mm D Weight: 9.2kg Options: 19-inch rack kit.

Typically < 100m s bet ween receiving the c om m and terminator for a step voltage change at the instrument and t he out put voltage beginning to change.

Installation Category II.

−40ºC to + 70ºC.

remote interfaces.

Performance levels achieved are detailed in the user manual.

EC Declaration of Conf ormity

We Thurlby Thandar Instruments Ltd

Glebe Road Huntingdon Cambridgeshire PE29 7DR England

declare that the

QPX1200L Power Supply with GPIB option

meets the intent of the EMC Directive 2004/108/EC and the Low Voltage Directive 2006/95/EC. Compliance was demonstrated by conformance to the following specifications which have been listed in the Official Journal of the European Comm unit ies.

EMC

Emissions: a) EN61326-1 (2006) Radiated, Class A

b) EN61326-1 (2006) Conducted, Class A c) EN61326-1 (2006) Har m onics, referring to EN61000-3-2 (2006)

Immunity: EN61326-1 (2006) Immunity Table 1, referring to:

a) EN61000-4-2 (2009) Electrostatic Discharg e b) EN61000-4-3 (2006) Electromagnetic Field c) EN61000-4-11 (2004) Voltage Interrupt d) EN61000-4-4 (2004) Fast Transient e) EN61000-4-5 (2006) Surge f) EN61000-4-6 (2009) Conducted RF

Safety EN61010-1 Installation Category II, Pollution Degree 2.

CHRIS W ILDING TECHNICAL DIRECTOR

2 January 2013

This instrument has been designed to meet the requirements of the EMC Directive 2004/108/EC. Compliance was demonstrated by meeting the test limits of the following standards:

Emissions

EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and Laboratory Use. Test limits used were:

a) Radiated: Class A b) Conducted: Class A c) Harm onics: EN61000-3-2 (2006) Class A; the instrument is Class A by product category.

Immunity

EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and Laboratory Use.

Test methods, limits and per formance achieved are shown below (requirement shown in brackets):

a) EN61000-4-2 (2009) Electrostatic Discharge : 4k V air, 4kV contact, Perfor m anc e A (B).

EMC

b) EN61000-4-3 (2006) Electromagnetic Field:

c) EN61000-4-11 (2004) Voltage Interrupt: ½ cycle and 1 cycle, 0%: Performance B (B); 25 cycles, 70%: Performance A (C); 250 cycles, 0%: Performance B ( C) , if Function 11 set (Output status at power-up same as at last power-down), ot her wise Perf ormance C.

d) EN61000-4-4 (2004) Fast Transient, 1kV peak (AC line), 0·5kV peak ( DC Out put), Performance B (B).

e) EN61000-4-5 (2006) Surge, 0·5kV (line t o line), 1kV (line to ground), Perfor m ance B ( B) . f) EN61000-4-6 (2009) Conducted RF, 3V, 80% AM at 1kHz (AC line only; DC Output

connections <3m, therefor e not tested), Performance A (A). According to EN61326-1 the definitions of performance criteria are:

Performance criterion A: ‘During test normal performance within the specification limits.’ Performance criterion B: ‘During t est, temporary degradation, or loss of function or

performance which is self-recovering’. Performance criterion C: ‘During t est, temporary degradation, or loss of function or

performance which requires operator int er vention or s ystem r es et occ ur s.’ Where Performance B is stated it is because DC Output regulation, or V & I m easur ement

accuracy, m ay deviate beyond Specification limits under the test conditions. However, the possible deviations are still small and unlikely to be a problem in practice.

Note that if operation in a high RF f ield is unavoidable it is good pract ice t o c onnect the PSU to the target system using screened leads which have been passed (toget her) through an absorbing ferrite sleeve fitted close to the PSU terminals.

Cautions

To ensure continued compliance with the EMC directive observe the following precautions:

3V/m, 80% AM at 1kHz, 80MHz – 1GHz: Performance B

1.4GHz to 2GHz: Performance A (A); 1V/m, 2.0GHz to 2.7GHz: Performance A (A).



minor regulation deviation at ~140MHz and ~250MHz at 3V/m.



(A) and

a) after opening the case for any reason ensur e that all signal and ground connections are

remade correctly and that case screws are correc t ly refitted and tightened.

b) In the event of part replacement becoming nec essary, only use components of an

identical type, see the Service Manual.

Safety

This power supply is a Safety Class I instrument according t o I EC classification and has been designed to meet the requirem ents of EN61010-1 (Safety Requirements for Elect r ical Eq uipm ent for Measurement, Control and Laborator y Use). It is an Installation Category II instrument intended for operation f r om a nor m al single phase supply.

This instrument has been tested in accordanc e with EN61010-1 and has been supplied in a safe condition. This instruction manual contains some information and warnings which have to be followed by the user to ensure safe operation and to r etain the inst r um ent in a safe condition.

This instrument has been designed f or indoor use in a Pollution Degree 2 environment in the temperature range 5°C to 40°C, 20% - 80% RH (non-condensing). It may occasionally be subjected to temperatures between +5°C and –10°C without degradation of its safety. Do not operate while condensation is present.

Use of this instrument in a manner not spec ified by these instructions may impair the safety protection provided. Do not operate the instrum ent outside its rat ed supply voltages or environmental range.

WARNING! THIS INSTRUMENT MUST BE EARTHED

Any interruption of the mains earth conduct or inside or outside t he inst r um ent will make the instrument dangerous. Int entional interruption is prohibited. The protective action must not be negated by the use of an extension cord without a protective conductor.

When the instrument is connected to its supply, terminals may be live and opening the covers or removal of parts (except those to which access can be gained by hand) is likely to expose live parts. The apparatus shall be disconnected from all voltage sources before it is opened for any adjustment, replacement, m aint enance or repair.

Capacitors inside the power supply may still be charged even if the power supply has been disconnected from all voltage sources but will be safely discharged about 10 m inut es af ter switching off power.

Any adjustment, maintenance and repair of the opened instrument under voltage shall be avoided as far as possible and, if inevitable, shall be carried out only by a skilled person who is aware of the hazard involved.

If the instrument is clearly def ec t ive, has been subject to mechanical damage, excessive moisture or chemical corrosion the safety protection may be impaired and the apparatus should be withdrawn from use and returned for checking and repair.

Make sure that only fuses with the required rated current and of the specified type are used for replacement. The use of makeshift fuses and the short-circuiting of fuse holders is pr ohibited.

Do not wet the instrument when cleaning it. The following symbols are used on the instrument and in this m anual:-

Earth (ground) terminal.

mains supply OFF.

mains supply ON. alternating current (ac)

direct current (dc)

Mains Operating Voltage

This instrument has a universal input range and will operate fr om a nominal 115V or 230V mains supply without adjustment. Check that the local supply meets the AC Input requirement given in the Specification.

Mains Lead

Connect the instrument to the AC supply using the mains lead provided. Should a mains plug be required for a different mains outlet socket, a suitably rated and approved mains lead set should be used which is fitted with the required wall plug and an IEC60320 C13 connector for t he instrument end. To determine t he m inimum current rating of the lead-set for the intended AC supply, refer to the power rating informat ion on t he equipment or in the Specification.

Any interruption of the mains earth conduct or inside or outside t he inst r um ent will make the instrument dangerous. Int entional interruption is prohibited.

Mounting

Installation

WARNING! THIS INSTRUMENT MUST BE EARTHED.

This instrument is suitable both for bench use and rack mounting. It is delivered with feet for bench mounting. The front feet include a tilt mechanism for optimal panel angle.

A rack kit for mounting in a 19” rack is available from the Manufacturers or their overseas agents.

Ventilation

The power supply is cooled by intelligent multi-speed fans which vent at the rear. Take care not to restrict the air inlets at the side panels or the exit at the r ear. In rack-mount ed s ituations allow adequate space around the instrument and/or use a fan tray for forced cooling.

Front Panel Connec tions

The load should be connected to the positive (red) and negat ive (black ) terminals marked OUTPUT. The terminals accept 4m m plugs into the end (but note that 4mm plugs will only support 32 Amps), 6mm diameter wire or plugs into the cross-hole or 8mm spade connections (with a maximum blade width of 16mm). The wiring and connectors must be capable of supporting the current required; for 50 Amps, 6mm

Remote sense connections to the load, if r equired, are made from the positive (+ ) and negative (−) REMOTE SENSE terminals. Remote sense operation is select ed from the keyboard or via a remote control interface; t he front panel REMOTE SENSE lamp is lit when remote sense is selected. Switching off remote sense ret ur ns the instrument to local sensing at the front panel output terminals.

cable is needed.

Connections

The terminal marked

is connected to the chassis and safety earth ground.

Rear Panel Connections

Output Terminals

The output and sense terminals are duplicated on the rear panel; these connections are paralleled with their front panel equivalents.

Remote sense operation is selected from the keyboard or via a remote control interface. When the rear panel terminals are used, remote sense should always be selected to ensure t hat output regulation is maintained within specification.

Logic Input

LOGIC IN is connected directly to the input of an isolating opto-coupler; there is no series resistor. The input is activated when a current greater than approximately 1mA is forced between LOGIC IN and LOGIC COMMON. The function of LOG IC IN is set from the keyboard.

Do not force a current exceeding 25mA between the terminals. Do not apply a voltage to LOGIC IN / LOGIC COMMON exceeding 50V with respect to

Logic Output

LOGIC OUT is the open-collector output of an opto-isolated NPN transistor that will sink up to 2mA when active (‘switch closure’). The function of LOGIC O UT is set from the keyboard.

The maximum operating voltage that can be applied between LOGIC O UT and LOGI C COMMON is 30VDC.

Do not apply external voltages between the terminals exceeding 30VDC.

Analogue Control

V CONTROL and I CONTROL provide quasi-analogue control of the Output Voltage and Current Limit respectively. The CONTRO L inputs are read 4 times per second by the A-to-D converter and the output is set according to the s elect ed input scaling . The input scaling for both can be set as 0 to 10 Volts or 0 to 5 Volts for m aximum output. The Analogue Control functions and scaling are both selected from the keyboard. The COMMON return signal is referenced to the positive output of the power supply.

Do not apply external voltages between the terminals exceeding 20VDC.

Pin Name

Description

Analogue Monitor

The output terminal voltage and output curr ent m ay be monitored on V MONITOR and I MONITOR respectively. The output scaling for both is the same as that set f or V CONTROL and I CONTROL, see previous section. The COMMON return signal is refer enced to the positive output of the power supply.

Do not apply external voltages to these terminals.

RS232

9−pin female D−connector with pin connections as shown below. Can be connected to a standard PC port using a fully wired 1:1 male-female cable without any cross-over connections.

1 RI 2 TXD Transmitted data from instrument 3 RXD Received data to instrument 4 CTS 5 GND Sig nal g r ound 6 RTS 7 DSR No internal connection 8 DTR 9 CD No internal connection

Passively asserted (+V through 10kΩ)

Signal ground is connected to instrument ground.

USB

The USB port is connected to instrument ground. It conforms with USB 2.0 (Full Speed) and accepts a standard USB cable. The Windows plug-and-play funct ions should aut om at ically recognise that the instrument has been c onnected. If the correct dr iver is not found, follow the Windows on-screen prompts and install the required files from the CD supplied.

LAN

The LAN interface is designed to meet LXI ( Lan eXtensions for Inst r um entat ion) version 1. 2; the instrument is Class C compliant. Remote cont r ol using the LAN interface is possible using a TCP/IP Socket protocol. The instrument also contains a basic Web server which provides information on the unit and allows it to be configur ed. Since it is possible to misconfigure the LAN interface, making it im poss ible to com municate with the instrument over LAN, a LAN Configuration Initialise (LCI) mechanism is pr ovided via a recessed switch on the rear panel (marked LAN RESET) to reset t he unit t o t he factory default.

Further details are given in the Remote Operation chapt er. For more inform at ion on LX I standards refer to www.lxistandard.org/home

GPIB – Factory Option

The GPIB signal grounds are connect ed to the instrument ground. The implemented subsets are:

SH1 AH1 T6 L4 LEO SR1 RL2 PP1 DC1 DT0 C0 E2

The GPIB address is set fr om t he front panel.

This section of the manual is a gener al intr oduction to the controls and operation of the instrument and is intended to be read befor e us ing the power supply for the first time.

In this manual front panel keys, connections and indicator s are shown in capitals, e.g. ESCAPE, JOG SET, OUT PUT, ON. Messages shown on the display are printed in a different type-font, e.g.

Enter V, Limits, CV, Store.

Switching On, Output On/Off

The power switch is located at the bottom left of the front panel. At power-up the default behaviour is for the instr ument's settings to be restor ed t o t hos e

automatically saved when it was switched off, but with the Output always off ( shown in the display). However, the us er can c hange this default setting such that t he O utput is

also restored at power-up to its status at power-down, see the Extra Functions section.

Initial Operation

OUTPUT OFF is

The DC Output is switched on and off electr onically with alternate press es of the ON lamp illuminates when the Output is on. At the same time the message above the VOLTS and AMPS display changes from

current) to indicate the present oper ating mode; should the load cause the instrument to oper ate outside its guaranteed power range the display will instead show

Keypad

Only the principles of operation are outlined here; the set ting of individual parameters is given in detail in later sections.

The paramount consideration in designing the user int er face has been to make changing set t ings as 'safe' as possible (i.e. with minimal risk of accidentally applying excessive voltages to a target system) whilst achieving ease of use. This has been achieved by requiring the user to confirm (OK) new numeric settings, with the option to ESCAPE at any point or even to simply pause until the operation times-out and the instr um ent r eturns to its original settings. In addition, display messages and LED indicators prompt, guide or warn the user such that entry or control errors are minimised. W her e s om e of these features (e.g . beeps) are considered unnecessary by regular users, the option exists to disable them, s ee t he Extra Func t ions sec t ion.

Under normal conditions the numeric keypad is disabled; pressing any key will cause the buzzer to beep, indicating an illegal operation. To set a voltage with the k eypad first press the V NUMERIC SET key; the VOLTS display changes to show the present set value in a smaller font, with the message Enter V or ESC below it, and the OK lamp starts flashing. The new value is then entered from the keyboard; as it is ent er ed it is displayed directly below the present setting, replacing the prom pt message. At any time during entry the new setting can be confirmed with the OK key, e.g. it is sufficient to key in 1, OK to change the setting to 1Volt. When OK is press ed t he display reverts to show just t he new sett ing in the full-size font and the OK lamp stops flashing; if OK is not pr es sed within 10 seconds of the last numeric key the entry is cancelled and the display returns to its original setting. If ESCAPE is pressed anytime in the entry procedure, entry is cancelled and the display returns to its orig inal set t ing. The current limit is set in exactly the same way after first pressing I NUMERIC SET.

key; the

OUTPUT OFF to CV (constant voltage) or CI (constant

UNREG (unregulated).

The OK key is used to confirm m ost keypad entries. At all other times it becomes the VIEW V/I LIMITS key and pressing it will cause the display to show preset output voltage and current limit for 3 seconds; during this per iod t he

Pressing SHIFT illuminates the ▲ lamp and gives the numeric keys the functions marked above them, e.g. STR (Store), RCL (Recall), etc. When a shift function is selected SHIFT is cancelled (the ▲ lamp is no longer lit). The fur t her key presses required to complete the select ed function are described in detail in the sections that follow; if no key is pressed within 10 seconds to complete the function, the function will terminate as if ESCAPE has been pressed. SHIFT is a toggle key; pressing SHIFT again when it has been selected will cancel SHIFT. SHIFT is also cancelled by ESCAPE, or by pressing SET V or SET I.

Limits message shows in the display.

Jog Control

The rotary 'jog' control per m its the output voltage or current limit to be incremented or decremented in steps with a resolution set by the JOG SET keys; the output im m ediat ely f ollows the setting, i.e. no OK is required.

At power-up jog is always off. To jog the voltage or curr ent setting press the V or I JOG SET key; the associated lamp will illuminate and the appropriate parameter display now changes to two lines. Wit h the output ON the top line continues to show the actual output, but t he addit ional lower display now shows the present

positioned under the digit that was last jogged. Whilst the V or I JOG SET indicator is lit, each further press of t he V or I key moves the JOG indicator one digit to the left ; the selection 'wrapsround' such that when the largest value of jog increment has been reached the next press returns it to the lowest. The default position at power-up is under the LSD, i.e. t he lowest jog increment is selected.

Turning the rotary jog control clockwise/anti-clock wise increments/decr ements the selected digit; digits to the left of the one being jogged are automatically incremented/decrem ent ed when the decade overflow/underflow point is reached. Digits to the right of the one being jogged remain unchanged unless the jog step overf lows/underflows the maximum/minimum settings in which case they are set to zero. For example, 59·861V goes to 59·961V goes to 60·000V for a 0.1V jog increment; 1.60A goes to 0·60A goes to 0·01A f or a 1A jog decrement.

The jog steps that can be selected are 1mV, 10mV, 100mV and 10mA, 100mA, 1A.

Limits value; in the lower display, the JOG indicator ( ) is

To disable the jog rotary contr ol pr ess t he JOG SET OFF key; reselecting JOG SET V or I will enable jog on the last used digit position. Jog is not cancelled by using numeric entry or any of the SHIFT functions but it is disabled whilst that function is enabled.

Note that the dual display of the parameter being j ogged is primarily of use if the output is O N; with the output off both lines of the display show the

as the parameter is jogged.

Display

At power-up the display briefly shows the instrument model number and installed firmware revision (Keyboard and Control firmware revision on the left; Interface firmware on the right) before reverting to the standard s tatus display.

The standard status display shows the voltage on the left (above the front panel VOLTS marking) and the current on the right ( above the front panel AMPS marking) together with the present output status, i.e. OUTPUT OFF, CV, CI, or UNREG; if the output is off then

shown in the display above the V and I values. The status of the LAN connection is also shown in the top left corner of t he display, as required for LXI compliance. Ref er t o the 'LAN Status Indication' paragraph in the LAN Interf ac e section for details. During other operations, however, the display capabilities are used more extensively to show, for example, prompts during function settings, e.g. m em ory store and recall operations or the extra functions access ed via the function; details are given in the relevant sections of this manual.

The display contrast is set at the f act ory but can be adjusted from the keyboard t o opt im ise it for particular ambient operating conditions. Press SHIFT, # , select Extra Function 90, and follow the on-screen prompts.

Limits value and change simultaneously

Limits is also

# shift

New users should first read the Initial Operation chapter which describes the operating principles of the keypad and rotary jog control.

Set Voltage

With the output off, the standard status display shows the set voltage; Limits shows as a reminder beside changes to load conditions, and the display shows the actual output voltage (measured at the sense point) ;

note that in CI mode the actual output voltage will be less than the set voltage. Both the set and actual voltage are shown to a resolution of 1mV. If the set voltage and load conditions cause the instrument to operate outside its guaranteed power range the display will show

(unregulated) and the actual output voltage will again be less than the set voltage. The voltage can be set directly from the numer ic keypad: press the NUMERIC SET V key, enter

the new value using the numeric keys and confirm by pressing OK. The broad principles of keypad entry are explained in the Initial Operation chapter, which should be read by new users.

When SET V is pressed the VOLTS display changes to show the present set value in a smaller font, with the message Enter V or ESC below it, and the O K lamp star ts flashing. The new

voltage is then entered from the k eyboard, e. g. 12·345V is entered as 1, 2, ·, 3, 4, 5. As it is entered it is displayed directly below the present setting, replacing the prompt message.

Manual Operation

OUTPUT OFF in the top line of the display. With the output ON the mode

CV (constant voltage) or CI (constant current ), depending on the set current limit and

UNREG

The minimum voltage setting is 0·000V; the maximum setting is 60· 000V. Pressing OK at any point will set the voltage entered with any remaining digits set to zero,

e.g. 1, 2, ·, 3, O K will set 12·300V; 1, OK will set 1·000V. When O K is pres sed t he s et voltage is changed and the display reverts to the standard status mode.

Pressing ESCAPE at any time during the sequence, or making no further k ey press within 10 seconds of the previous one will cause the display to return to its original reading before SET V was pressed.

Entering a voltage outside the range maximum (including tr ying t o ent er 3 digits before the decimal point) or trying to enter mor e t han 5 digits will cause the buzzer to beep; the last key entry will be ignored.

The voltage can also be set using the Jog contr ol. Pr es sing JOG SET V will illuminate the V JOG SET lamp and the VOLTS display will again change to two lines. With the out put O N t he top line continues to show the actual output, but the additional lower display now shows the present

that was last jogged. Whilst the V SET lamp is lit, each further pr es s will move the indicator one digit to the left; the s elect ion ' wraps round' such t hat when the largest value of jog increment has been reached the next press retur ns it t o the lowest. The default position at power-up is under the LSD, i.e. the lowest jog increment is selected. The jog steps that can be selected are 1mV, 10mV and 100mV.

With jog enabled the output voltage can be incremented or decrement ed with the rotar y jog control with a step resolution indicated by the position of the immediately follows the setting, i.e. no OK is required. In CV (constant voltage) mode the actual output voltage shown in the upper display line will follow the set voltage being ‘Jogged’ in the lower display; however, if t he out put goes into constant current mode (indicated by the CV status message being replaced by CI) the upper display, showing actual voltage, will show a value which is less than the set voltage.

Limits value; in the lower display, the JOG indicat or ( ) is positioned under the digit

JOG

JOG indicator. The output

Note that the dual display during JOG SET V is primarily of use if the output is ON; with the output off both lines of the display show the

voltage is jogged.

Limits value and change simultaneously as the

Set Current Limit

With the out put off, the standard status display shows the set current limit; with the output on it shows the actual output current in all modes (CV, CI or UNREG). Both the actual current and the current limit are shown to a resolution of 10mA.

The current limit can be set directly f r om the numeric keypad: press the NUMERIC SET I key, enter the new value using the numeric keys and confirm by pressing OK. The broad principles of keypad entry are explained in the Initial Operation chapter, which should be read by new users.

When SET I is pressed the AMPS display changes to show the present current limit value in a smaller font, with the message Enter I or ESC below it, and the O K lam p starts flashing.

The new current limit is then entered fr om the keyboard, e.g. 12·34A is entered as 1, 2, ·, 3, 4. As it is entered it is displayed directly below the present setting, replacing t he pr om pt message.

The minimum current setting is 0·01A; the maximum setting is 50.00A, i.e. t here is no over-range capability.

Pressing OK at any point will set the current entered with any remaining digits set to zero, e.g. 1, 2 ·, 3, OK will set 12·30A; 1, O K will set 1·00A. When OK is pressed the curr ent limit is changed and the display reverts to the standard status mode.

Pressing ESCAPE at any time during the sequence, or making no key press within 10 seconds of the previous one will cause the display to return to its original reading before SET I was pressed.

Entering a value outside the range maximum (including trying t o ent er 3 digits before the decimal point) or trying to enter more than 4 digits will cause the buzzer to beep; the last key entry will be ignored.

The current limit can also be set using t he r otar y jog control. Pressing JOG SET I will illuminate the I JOG SET lamp and the AMPS display will again chang e to two lines. With the output ON the top line continues to show the actual output, but the addit ional lower display now shows the present current limit; in the lower display, the JOG indicator ( was last jogged. Whilst the I SET lamp is lit, each further press will move the one digit to the left; the selection ' wraps round' such t hat when the largest value of jog increment has been reached the next press returns it to t he lowest. The def ault posit ion at power-up is under the LSD, i.e. the lowest jog increment is select ed. The jog steps that can be selected are 10mA , 100mA and 1A.

With jog enabled the current limit can be incremented or decrem ented with the rotary jog control with a step resolution indicated by the position of the follows the setting, i.e. no OK is required. With t he out put ON and in CV mode the upper line of the display showing actual current will be a lower value than the current limit being ‘Jogged’ in the lower display; however, if t he out put goes into constant current mode (indicated by the CV status message being replaced by CI) the upper display, showing actual current, will follow the current limit value being ‘Jogged’ in the lower display.

Note that the dual display during JOG SET I is primarily of use if t he output is ON; with the output off both lines of the display show the

limit is jogged.

Limits value and change simultaneously as the current

JOG indicator. The output immediately

) is positioned under the digit that

JOG indicator

Instantaneous Current Output

The current limit control can be set t o limit the continuous output current to levels down to 10mA. However, in com m on with all precision bench power supplies, a capacitor is connected acr os s the output to maintain stability and good transient response. This capacitor charges to the output voltage and short-circuiting of the output will produce a current pulse as the capacitor discharges which is independent of the current limit setting .

Output Power (V x A)

If SHIFT, V x A is pr ess ed t he display shows the product of measured output voltage x measured current in the form

for V and I. Pressing ESCAPE cancels V x A mode.

nn.n VA. . The V x A value is updat ed at the same measurement rate as

Calculated Load Impedance (V/A)

If SHIFT, V/ A is pressed the display shows the calculated result of measured output voltage ÷ measured current; this is a sampled result which can be updated by f ur t her presses of the OK key. Pr essing ESCAPE cancels V/A m ode.

The display shows the calculated nominal V/A value with a resolution of 5 significant digits (10µΩ resolution for V/A <1Ω). The accuracy is calculated from the uncertainty of t he individual voltage and current measurements and is indicated by showing the minimum and maximum possible values (in brackets) beside the nominal. The uncertainty is worst when either (or both) V and I are small.

This function is extremely useful f or m eas ur ing low impedances at high currents, e.g. power MOSFETs. Always use the Remote Sensing function to eliminate t he effects of connecting lead and contact resistance when making low value V/A measurements.

Current Measurement Averaging

DS(on) of

Press SHIFT, I the mode status. The AMPS reading is still updated at the same rate (4 times per second) but the

value displayed is the rolling average of the last 4 current measur em ents m ade.

to select current averaging; I

AVG

Connection to the Load

The load should be connected to the positive (red) and negat ive (black ) OUTPUT terminals. Both are fully floating and either can be connect ed to ground.

Remote Sensing

The instrument has a very low output impedance, but this is inevitably increased by the resistance of the connecting leads and the contact resistance between terminals and leads. At high currents this can result in signif icant differences between the indicated source voltage and the actual load voltage (even two 2mΩ connecting leads will drop 0·2V at 50 Amps, for instance). This problem can be minimised by using short, thick, connecting leads, but where necessary it can be completely overcome by using the remote sense capability.

This requires the sense term inals to be c onnect ed to the output at the load instead of at the source; insert wires into the spring-loaded REMOTE SENSE terminals and connect direc t ly to the load.

Select remote sense by pressing SHIFT, SENSE; the message

OK to confirm, ESCAPE to cancel is shown in the display and the OK lamp flashes.

Press OK to confirm or pres s ESCAPE to exit without changing state; the REMOTE SENSE lamp above the front panel terminals lights when remote sense is selected. Remote sense is turned off by pressing SHIFT, SENSE again; the message

confirm, ESCAPE to cancel is shown in the display and the OK lamp flashes. Press

OK to confirm or press ESCAPE to exit without changing stat e; the REMOTE SENSE lamp above the front panel terminals is off when remote sense is deselected.

shows in the top line of the display beside

AVG

Turn On Remote sense?

Turn Off Remote Sense? OK to

To avoid instability and transient response problems, care m ust be taken to ensure good coupling between each output and sense lead; this can best be done by twisting the leads tog et her. An electrolytic capacitor directly across the load connection point may also be beneficial.

The voltage drop in each output lead must not exceed 1 Volt. The power supply has rear panel output and sense terminals, appropriate for when the

instrument is used in a rack. The rear panel remote sens e t er m inals should always be used with the rear panel output connections.

Sense Miswiring Trip

The output will be tripped off if the voltage between an output ter m inal and its corres ponding sense terminal exceeds approximately 1V; this will happen if the sense wires are wired at the load to the wrong output or if an att em pt is m ade to draw power from the sense wires.

If the sense terminals are m iswired in this way the output is turned off and the message Sense

Error – Check Connections is displayed. Pressing ESCAPE at this point removes the

message and the display now shows the preset voltage and current limit. When the cause of the trip has been corrected the output can be turned on again.

Series or Parallel Connection with Other Outputs

The outputs of the power supply are fully floating and m ay be used in series with other power supply units to generate high DC voltages up to 300VDC.

The maximum permissible voltage between any terminal and earth ground ( WARNING! Such voltages are exceedingly hazardous and great care should be taken to shield

the output terminals for suc h use. On no account should the output terminals be touched when the unit is switched on under such use. All connections to the terminals must be made with the power switched off on all units.

It should be noted that the unit can only source current and cannot sink it, thus units cannot be series connected in anti-phase.

The unit can be connected in parallel with others to produce higher currents. Where several units are connected in parallel, the output voltage will be equal to that of the unit with the highes t output voltage setting until the current dr awn exceeds its current limit s et ting, upon which the output will fall to that of the next highest setting, and so on. In constant current m ode, units can be connected in parallel to provide a current equal to the sum of t he c ur r ent limit settings.

Note that the output terminals are rated at 60A maximum; if several outputs are operated in parallel to source higher currents than this the junction should be made at a separate point, not one of the terminals.

Over-Voltage Protection

Over-Voltage Protection (OVP) can be set from 2·0V to 65.0V. If the output voltage exceeds the set OVP the output is immediately turned off (typically within 100µs), thus avoiding damage to t he circuit under test. The OVP circuit will trip if an excessive voltage is accidentally set from the front panel or via a remote control interface, or is the result of a failure in t he c ont r ol cir cuit r y of the instrument itself. OVP will also trip if an excessive voltage is impressed across the terminals from an external source; however, when the output is tripped off, the external voltage will still be present and it is up to the user to remove the sour c e t o avoid possible damag e.

) is 300VDC.

To set OVP press SHIFT, OVP. The display changes to show only the present together with the prompt new OVP value using the numeric keypad, exactly as described for setting output voltage, and

press OK to confirm the new setting; to exit without entering a new value press ESCAPE. The factory default setting is 65·0V.

If the OVP is tripped the display shows the message the output is turned off. Press ing ESCAPE at this point r em oves the message and the display

now shows the preset voltage and current limit. When the cause of the OVP has been removed (or the OVP limit changed) the output can be turned on again.

Note also that it is possible and valid to set OVP below the set voltage. If the supply is in constant current mode the output voltage will be below the set voltage; OVP could be set such that is was above the actual output voltage but below the set voltage. This could be used to trip the output under a fault condition which caused the load impedance to incr ease and t he ac t ual output voltage to therefore rise above the O VP point.

Numeric Entry: Range 2-65 ; the OK lamp flashes. Enter t he

OVP - Press ESC to Reset and

OVP setting

Over-Current Protection

Over-Current Pr otection (OCP) can be set from 2.0A to 55.0A. If the output c ur r ent exceeds the set OCP the output is shut down (typically within 100ms).

To set OCP press SHIFT, OCP. The display changes to show only the present together with the prompt new OCP value using the numeric keypad, exactly as described for setting the current limit, and

press OK to confirm the new setting; to exit without entering a new value press ESCAPE. The factory default setting is 55·0V.

If the OCP is tripped the display shows the message the output is turned off. Press ing ESCAPE at this point r em oves the message and the display

now shows the preset voltage and current limit. When the cause of the OCP has been removed (or the OCP limit changed) the output can be turned on again.

Note also that it is possible and valid to set OCP below the set current limit. For example, the power supply may be used to repetitively test a unit under test (UUT) which normally takes a peak current of, say, 10 Amps. However, a faulty UUT would take a current of more than 10 Amps and would be damaged by being left in a 10 Amp current-limited state. In this case the current limit could be set to 11A, say, and the OCP set to 10A to ensure that a faulty UUT will trip the supply off.

Numeric Entry: Range 2-55 ; the OK lamp flashes. Enter t he

Output Protection

In addition to OVP and OCP for forward over-voltage and over-current protect ion, the output is protected from reverse voltages by a diode; the cont inuous r everse cur rent must not exceed 3 Amps although transients can be much higher.

Temperature Trip and Other Faults

If the safe internal t em perature limit is exceeded because, for example, the fan vents have been blocked, the output is automatically tripped off. The display will show a message indicating that a fault has occurred and that the AC supply must be turned off and on again to reset the unit. If over-temperature is suspected, the cause of the fault should be rectified and the unit allowed to cool before the AC supply is turned on again.

Note that an over-temperature tr ip shuts down the primar y side of the instrument and it is that condition that is detected and causes the f ault m ess age to be displayed. However, other faults may occur which would also cause the primary side to shut down and these will not be distinguishable from an over-temper ature trip. If the unit does not r es tart after being allowed to cool then another fault might be pr es ent and the unit should be returned for service.

OCP setting

OCP - Press ESC to Reset and

Logic Control Input and Output

Digital signal connections LOGIC IN and LOGIC OUT are available on the rear panel; press t he orange actuators of t he s cr ewless ter m inals, inser t the connecting wire and release the actuator to secure the connection. LOGIC I N is connected directly to the input of an isolating opto-coupler; there is no series resistor. The input is active when an input current greater than approximately 1mA is forced between LOGIC IN and LOGIC COMMON. LOGIC IN can be set to enable the output, disable the output, or be ignor ed when it is activated, s ee t he Extra Func t ions sec t ion. Note that LOGIC IN can only be used to enable/disable the output if the output has already been

turned ON with the front panel panel also that, having turned the output ON with the

output is disabled by the LOGIC IN signal. LOGIC OUT is an isolated rear-panel open-collector output that will sink up to 2mA when active

(‘switch closure’); the maximum voltage that can be applied to LOGI C OUT is 30Vdc. LOGIC OUT can be set to be ‘closed’ or ‘open’ for output enabled or disabled, current limit (CI mode), power limit (UNREG mode), or for any fault t rip. The default condition is for LOGIC OUT to be ‘closed’ for the Output ON; loss of AC power, which would deactivate the opto, is also reliably detected with this setting. See Extra Functions sect ion for further details.

key to be used to turn the output off in an emergency, i.e. to override LOGIC IN. Note

key or by remote interface com m and; this permits the front

key, the ON lamp remains lit even when the

Analogue Control

Rear panel connections V CONTROL and I CONTROL provide quasi-analogue control of the Output Voltage and Current Limit respectively. The CONTROL inputs are read 4 times per second by the A-to-D converter and the output is set according to the selected input scaling. The input scaling for both can be set as 0 t o 10 Volts or 0 to 5 Volts for maximum output. The Analogue Control functions and scaling are both s elect ed from the keyboard, see Extra Functions section.

The COMMON return signal is referenced to the posit ive output of the power supply. Analogue Control is activated from the Bus menu, s ee Remote Operation section. When

activated, the top line of the display shows which functions (V and/or I) have been selected and the corresponding functions on t he front panel (NUMERIC SET / JOG SET for V and/or I ) are inhibited to avoid contention between Analogue Control and front panel operation.

Analogue Monitor

The output terminal voltage and output curr ent m ay be monitored on V MONITOR and I MONITOR respectively. The output scaling for both will be the same as that set for V CONTROL and I CONTROL, see above section. V MONITOR and I MONITOR are always available at the rear panel terminals.

The COMMON return signal is referenced to the posit ive output of the power supply.

Store Settings

The instrument can store 10 set -ups in non-volatile memory; the parameters stored are voltage, current limit, OVP and OCP. The output state and remote sense sett ing are not stored. To store a set-up pr ess SHIFT, STORE to show the store locations and the currently saved setups on the

The store location to be used can be selected directly by pressing any key 0 – 9 or by scrolling to the appropriate store number in the list using the JOG SET control; the selected store is indicated by the square brackets

selected location; the screen returns t o t he s tandard s tatus display. A full store can be overwritten with new settings. At any time before the OK key is pressed the store function can be exited without saving a set-up by pressing ESCAPE or by waiting for the operation to time out .

Store screen.

Deleting Stored Settings

Any store can be returned to 'empty' as follows: press SHIFT, STORE, and select the appropriate store number as described in the Store Settings section above; at that point pr ess

OK to confirm the operation. At any time before the OK k ey is pressed the delete function can be exited without erasing a set-up by pressing ESCAPE or by waiting for the operation t o t im e out .

Recall Settings

To recall a set-up press SHIFT, RECALL to show the st or e locat ions and t he currently saved setups on the

limit, OVP and OCP settings; the output status (on/off) and s ense s et t ings (local/remote) are not stored. Empty store locations are shown without data.

Recall screen. Each store location is displayed with its output voltage, current

[ ] at that location. Press OK to st or e the set-up at the

· followed by

The store location containing the setting to be recalled can be selected directly by pressing any key 0 – 9 or by scrolling to the appropriate stor e num ber in t he list us ing the JOG SET control; the selected store is indicated by the square brackets

the set-up at the selected location; the s cr een r eturns to the standard status display. Settings may be recalled with the output on or off.

[ ] at that location. Press OK t o r ecall

# Code

Function

Output always off at power-up (factory def ault)

Output status at power-up same as at last power-down

LOGIC OUT 'closed' for Output ON, 'open' for Output OFF (factory default)

LOGIC OUT ‘closed' for Output OFF, 'open' for O ut put ON

LOGIC OUT ‘closed’ for any trip

LOGIC OUT ‘open’ for any trip

LOGIC OUT ‘closed’ for UNREG

LOGIC OUT ’open’ for UNREG

LOGIC OUT ‘closed’ for CI (current limit)

LOGIC OUT ‘open’ for CI (current limit)

Buzzer on. A single beep indicates a wrong entry (factory default)

Buzzer off

V CONTROL and I CONTROL both selected (factory default)

V CONTROL only selected

I CONTROL only selected

V CONTROL and I CONTROL scaling 0 to 10 Volts (factory default)

V CONTROL and I CONTROL scaling 0 to 5 Volts

LOGIC IN ignored (fac t or y default)

LOGIC IN active enables output

LOGIC IN active disables output

LCD contrast adjustment

Restores factory defaults, including these # settings

Enter calibration mode. Refer to Ser vice Manual

Voltage:

0.000V

Current Limit:

1.00A

OVP:

65.0V

OCP:

55.0A

Output:

Output off; local sense

Extra Functions

Options for extra functions such as LOGIC CONTROL and ANALOGUE CONTROL/MONITOR, plus variations on some of the factor y default functions, can be set by the user by using the # extra functions facility. The complete list of functions is accessed by pressing SHIFT, # ; the required function can be selected direct ly by entering nn from the keyboard, where nn is the 2digit number in the list below, or by scrolling to the appropriate function in the list using the JO G SET control; the selected function is indicated by the squar e br ackets

list. Press OK to initiate the selected function, following the on-screen prompts where appropriate. At any time before the OK key is pressed the extra function can be exited without implementation by pressing ESCAPE or by waiting for the operation to time out .

Selected functions are indicated by a  beside the code in the on-screen list. Note that t he options within any decade group are mutually exclusive and selecting a function within any group will automatically deselect any previously selected function in that group, including the factory default option; for example, if # 26 is selected, 20 -25 and 27 are all deselected.

[ ] at that position in the

Factory Default Settings

The ex-factory default settings (which will apply at first power-up) are as follows:

# Settings: 10, 20, 30, 40, 50, 60 active



The instrument can be remotely controlled via its RS232, USB, GPIB (factory option), LAN or Analogue interfaces.

USB remote control operates in a similar way to RS232 but via the USB connector. Software supplied with the instrument sets up the controlling computer t o treat the USB connection as a virtual COM port. Application software on the computer can then access the instrument via that COM port.

Analogue remote control is activated fr om the BUS menu but the functions (V and/or I) and scaling are set from the Extr a Functions menu, see previous section.

Bus and Address Selection

Press SHIFT, BUS to display the bus class – Digital or Analogue Remote. The present selection is indicated with a

(0 or 1) beside the class or by moving to the requir ed t ype using t he JOG SET control; the selected bus is indicated by the square brackets [ ] . Pr ess O K t o s elect t he bus class. At any time before the OK key is pressed t he s elect ion can be exited without chang e by pressing ESCAPE.

If Analogue Remote has been selected, pressing OK ret ur ns the display to the standard status screen.

Digital has been selected, pressing OK changes t he display to show the current digital

If interface using the JOG SET control. Press OK to confirm and return to the standard status scr een.

Setting the address is essential for GPIB operation but use can be made of the ADDRESS? command over any of the other interfaces to easily identify which instrument is being controlled by a particular COM port (for RS232 or USB) or TCP socket (for LAN). Note t hat the LAN interface also has a separate 'Identify' function, accessible from t he inst r um ent's web pages, that flashes the instrument's display until the function is cancelled.

If analogue is selected then the dig ital interfaces may be used to query the instrument but not t o change any settings.

Address and the message Set Address with Jog. Change the address

. The bus class can be changed directly by keying in the number

Remote Operation

Interface Locking

All interfaces are live at all times; this removes the need to select the active interface and is also a LXI requirement. To reduce the risk of the instrument being inadvertently under the control of two interfaces at once a simple lock and release m echanism is pr ovided in the instr uction set. The lock is automatically released where it is possible to detect disconnection and when the local button is pressed. Access to the interfaces may also be restricted using t he web pages.

Any interface may request to have exclusive control of t he inst r um ent by sending an “IFLOCK” command. The lock may only be released by sending an “IFUNLOCK” command fr om the interface instance that current ly has the lock and may be queried from any interface by sending an “IFLOCK?” command. The reply to any of these comm ands will be “-1” if the lock is owned by another interface instance, “0” if the interface is free and “ 1” if the lock is owned by the requesting interf ace instance. Sending any comm and from an interface without control privileges that attempts to change the inst rument status will set bit 4 of the Standard Event Stat us Register and put 200 into the Execution Error Register to indicate that there are not sufficient privileges for the required action.

Note: it is also possible to configure the pr ivileges for a particular interface to either ‘read only’ or ‘no access’ from the Web page interface.

Name

Description

Start Bits: 1

Parity: None

Data Bits: 8

Stop Bits: 1

Remote/Local Operation

At power-on the instrument will be in the local state. In this state all keyboard operat ions ar e possible. When the inst r ument is addressed to listen and a command is received the remote state will be entered and REMOTE will be shown in the top line of the display. In this state the keyboard is locked out and remote comm ands only will be processed. The instrument m ay be returned to the local state by pressing the LOCAL key; however, the effect of this action will only remain until the instrument is addressed ag ain or receives another character from the inter face, when the remote state will once again be entered.

RS232 Interface

RS232 Interface Connector

The 9-way D-type serial interface connector is located on the instrument r ear panel. The pin connections are as shown below:

1 RI Passively asserted (+V through 10kΩ) 2 TXD Transmitted data from instrument 3 RXD Received data to instrument 4 CTS 5 GND Signal ground 6 RTS Passively asserted (+V through 10kΩ) 7 DSR No internal connection 8 DTR 9 CD No internal connection

RS232 Connections

The RS232 interface should be connected to a standard PC port us ing a fully wired 1:1 malefemale cable without any cross-over connections. Alternatively, only pins 2, 3 and 5 need be connected to the PC, but with links made in the connector at the PC end between pins 1, 4 and 6 and between pins 7 and 8, see diagram.

Baud Rate for this instrument is fixed at 9600; the other parameters are fixed as f ollows:

RS232 Character Set

Because of the need for XO N/ XOFF handshake it is possible to send ASCII coded data only; binary blocks are not allowed. Bit 7 of ASCII codes is ignored, i.e. assumed to be low. No distinction is made between upper and lower case characters in command mnemonics and t hey may be freely mixed. The ASCII codes below 20H (space) are not used. In this manual 20H, etc. means 20 in hexadecimal.

USB Interface

The USB interface allows the instrument to be cont r olled using RS232 protocol via a computer’s USB port. The instrument is supplied with a CD containing an .inf file f or t he s tandard Microsoft drivers available in Windows 2000, XP and Vista. Any updates are available via the TTi website, www.tti-test.com.

Installation of the interface dr iver is achieved by connecting the inst r um ent to a PC via a standard USB cable. The Windows’ plug and play functions should automatically recognise the addition of new hardware attached to the USB interface and, if this is the first time the connection has been made, prompt for t he locat ion of a suitable driver. Provided that the standard Windows prompts are followed correctly Windows will install the appropriate driver and establish a virtual COM port within the PC. The number of the new COM port will depend upon the number of co-existing COM ports within the PC. The virtual COM port can be driven by Windows applications in exactly the same way as a standard COM port, except that the Baud rate setting of the virtual COM port is ignored.

The driver will remain installed on the PC so that the establishment of a virtual COM port is done automatically each time the instrument is connected t o t he PC via USB in the fut ur e.

Further virtual COM ports are created for each additional instr ument connected to the PC via USB. Each instrument is assigned a separate virtual COM port when it is first c onnected and the same COM port will be assigned each time that instrument is subseq uently connected; the PC software makes use of the uniq ue code embedded in each instrument to link it to the same virtual COM port irrespective of which physical USB port it is connected to.

LAN Interface

The LAN interface is designed to comply with the LXI standard version 1. 2 Class C and contains the interfaces and protocols descr ibed below. Since it is possible to misconfigure the LAN interface, making it impos sible to c om m unicat e with the inst r um ent over LAN, a LAN Configuration Initialise (LCI) mechanism is pr ovided via a recessed switch on the rear panel to reset the unit to the factory default. The default setting is for the instrument to attempt t o obtain settings via DHCP if available or, if DHCP times out (30 seconds), via Auto-IP. Resetting the LAN removes any password protection.

For more information on LXI s tandards refer to www.lxistandard.org/home

LAN Connection

To use the LAN interface, the I P addr es s of the unit must be known. There is a LXI Discovery Tool on the supplied CD-ROM which can be used to display the IP addresses (and other associated information) of all connect ed devices that comply with the VXI-11 discovery protocol. This tool is a Windows PC application that should be installed and run on the cont r olling PC with the unit either connected directly to the PC network connect or or via a router. Connecting via a router is recommended as this is significantly quicker to assign an IP address; connecting directly to the PC will begin to assign an IP address only after a 30 second DHCP timeout. Double clicking on any entry in the list of devices discovered will open the PC's web browser and display the Home page of that device.

There are also tools for LAN discovery included as part of t he Nat ional Ins t r uments Measurement and Automation Explorer package and the Agilent Vee application.

The unit will, when first powered up, attempt to obt a in s e ttings via DHCP if available or , if DHCP times out (30 seconds), via Auto-IP. O t her wise a static IP address of 192.168.0.100 is assigned.

then the LAN status indicator is .

for DHCP. The LAN status indicator is animated flashing between and

display becomes

use by another device. Communication is not possible and the display shows

LAN Status Indic ation

The LAN Status is displayed in the top left hand corner of the display during normal operation. It is not shown on all menus. There are 4 possible indications:

No LAN

Configuring The unit has det ected a LAN connection but is not yet configured, e.g. is waiting

LAN OK The LAN connection is now configured and the unit can communicate. The

LAN FAULT The unit has detected a problem with LAN connection, e.g. Its IP address is in

If the unit cannot detect any connect ion t o a LAN e.g. the cable is unplugged

LAN Identify

The instrument's main web page has an 'Identify' function which allows the user to send an identifying command to the instr um ent which causes its display to flash unt il the command is cancelled.

Web Server; Configuration Password Protecti on

The unit contains a basic web server. This provides informat ion on the instrument and allows it to be configured. The Configure page can be password protected to det er unaut hor ised c hanges to the remote operation conf ig uration; the default configur at ion is ‘no password’.

The Configure page itself explains how to set the password. The password can be up to 15 characters long; note that t he User Name should be left blank. The password will, however, be reset to the default (no password) if the rear panel LAN RESET switch is used to reset all the LAN parameters to their fact ory default.

The web pages also have an ‘Identify’ function which allows the user to send an identifying command to the instrument which causes its display to f lash unt il the command is cancelled.

ICMP Ping Server

The unit contains an ICMP server allowing the instrument to be ‘pinged’ via either its host name or IP address.

VXI-11 Discovery Protocol

The instrument has very limited support of VX I-11 which is sufficient for the discovery protocol and no more.

The instrument implements a Sun RPC Port-m apper on TCP port 111 and UDP port 111 as defined in RPC1183. The calls supported are: NULL, G ET PORT and DUMP.

On TCP port 1024 a very simple VXI-11 protocol is implemented s ufficient only for instrument discovery. This implements the following calls: CREATE LINK, DEVICE_WRITE, DEVICE_READ and DESTROY_LINK.

Once a link has been created anything written to the device is ignored and any read from the device returns the identification string as would be expected from a “*IDN?” of the form

‘Manufacturer,Model,Serial No.,X.xx – Y.yy’ for example THURLBY THANDAR, QPX1200, 279730, 3.00 – 1.00

where ‘X.xx’ is the r evision of t he m ain firmware and ‘Y.yy’ is the revision of the int er face firmware. Interf ace firmware is user field updateable via the USB port.

Service Request

SR1

Controller

XML Identification Document URL

As required by the LXI standard, t he inst r ument provides an XML identification document that can be queried via a GET at “http:/ / < hostname>:80/lxi/identification” that conforms to the LXI XSD Schema (available at http://www.lxistandard.org/Instrum entIdentification/1.0) and the W3C XML Schema Standards ( http://www.w3.org/XML/Schema instrument.

TCP Sockets

The instrument uses 2 sockets on TCP port 9221 for instr um ent control and monitoring. Text commands are sent to this port as defined in ‘Remote Commands’ and any replies are returned via the same port. Any string must be one or more complete commands. Commands m ay be separated with either semicolons “;” or line feeds. No ter minator is required since the TCP frame contains complete commands though comm ands may be sent with a terminator if desired (it will be ignored). Each command over TCP behaves as if it is terminated with a command terminat or (ASCII character 0AH, line feed).

GPIB Interface

The GPIB interface 24-way connector is located on t he inst r um ent rear panel. The pin connections are as specified in IEEE Std. 488.1-1987 and the instrument complies with IEEE Std.

488.1-1987 and IEEE Std. 488.2-1987.

). This document describes the

GPIB Subsets

This instrument contains the following IEEE 488.1 subs ets:

Source Handshake SH1 Acceptor Handshake AH1 Talker T6 Listener L4

Remote Local RL2 Parallel Poll PP1 Device Clear DC1 Device Trigger DT0

Electrical Interface E2

Query Error Register - GPIB IEEE Std. 488.2 Error Handl ing

The IEEE 488.2 UNTERMINATED error (addressed to talk with nothing t o say) is handled as follows. If the inst rument is addressed to talk and the response formatter is inactive and the input queue is empty then the be set in the Standard Event Status Register, a value of 3 to be placed in the Query Error Register and the parser to be reset. See t he Status Reporting section f or further information.

UNTERMINATED error is generated. This will cause the Query Error bit to

The IEEE 488.2 INTERRUPTED error is handled as follows. If t he r es ponse formatter is waiting to send a response message and a or the input queue contains more than one END messag e then the instrument has been

INTERRUPTED and an error is generated. This will cause the Query Error bit to be set in t he

Standard Event Status Register, a value of 1 to be placed in the Query Error Regist er and t he response formatter to be reset thus clearing the output queue. The parser will then start parsing the next further inform at ion.

<PROGRAM MESSAGE TERMINATOR> has been read by the parser

<PROGRAM MESSAGE UNIT> from the input queue. See the Status Reporting section for

bit 7 =

don't care

bit 6 =

bit 3 =

Sense

sense of the response bit; 0 = low, 1 = high

bit 2 =

? bit 1 =

bit position of the response

The IEEE 488.2 DEADLOCK error is handled as f ollows. If the response formatter is waiting t o send a response message and the input q ueue bec om es full then the instrument enters t he

DEADLOCK state and an error is generated. This will cause the Query Error bit to be set in the

Standard Event Status Register, a value of 2 to be placed in the Query Error Regist er and t he response formatter to be reset thus clearing the output q ueue. The parser will then start parsing the next

<PROGRAM MESSAGE UNIT> from the input queue. See the Status Reporting section for

further inform at ion.

GPIB Parallel Poll

Complete parallel poll capabilities are offered on this instrument. The Parallel Poll Enable Register is set to specify which bits in the Status Byte Register are to be used to form t he message The Parallel Poll Enable Register is set by the *PRE <nrf> comm and and r ead by the *PRE? command. The value in the Parallel Poll Enable Register is ANDed with the Status Byte Register; if the result is zero t hen t he value of

ist local

ist is 0 otherwise the value of ist is 1.

The instrument must also be configured so that the value of

ist can be returned to the controller

during a parallel poll operation. The instrument is configured by the cont r oller sending a Parallel Poll Configure command (PPC) followed by a Parallel Poll Enable command (PPE). The bits in the PPE command are shown below:

bit 5 = 1 Parallel poll enable bit 4 = 0

bit 0 = ?

Example. To return the RQS bit (bit 6 of the Status Byte Register) as a 1 when true and a 0 when

false in bit position 1 in response to a parallel poll operation send the following commands

*PRE 64

<pmt>, then PPC followed by 69H (PPE)

The parallel poll response from the instrument will then be 00H if RQS is 0 and 01H if RQS is 1.

During parallel poll response the DIO interface lines are resist ively terminated ( passive termination). This allows multiple devices to share the same response bit position in either wiredAND or wired-OR configuration, see IEEE 488.1 for more infor m ation.

Status Reporting

A separate error and status model is maintained for each int er face instance; an interface instance is defined as a potential connection. USB, GPIB and RS232 are inherently single connect ions s o represent one interface instance each. LAN, however, allows for multiple simultaneous connections and therefore represents m ult iple inter face instances. Two inter face instances are allocated to the two TCP socket interfaces and one more is allocated to the Web page interface. Having a separate model for each int er face instance ensures that data does not get lost as many commands e.g. ‘*ESR?’ clear the contents on read.

Error status is maintained using a set of registers; these are described in the following paragraphs and shown on the Status Model at the end of this section.

Bit 7 -

Power On. Set when power is first applied to the instrument.

Bit 6 -

Not used.

The parser is reset and parsing continues at the next byte in the input s t r eam .

Execution Error Register, see Error Messages section.

not reached within 5 secs, e.g. output voltage is slowed by a large capacitor on the out put .

reported in the Query Error Register.

Bit 1 -

Not used.

Bit 0 -

Operation Complete: Set in response to the ‘*O PC’ command.

No error encountered.

1- 9

Indicates a hardware error has been encountered.

numbers, illegal store numbers, num ber s > 1 where only 0 and 1 are allowed, etc.

by writing data to the store again.

102

A recall of set up data has been requested but the store specified does not contain any data.

103

Attempt to read or write a command on t he second output. The unit is single output only.

without write privileges. See ‘Interface Locking’ section for details

St andard Ev ent Status and Standard Event St at us Enabl e Regist ers

These two registers are implemented as r equired by the IEEE Std. 488.2. Any bits set in the Standard Event Status Register which correspond t o bits s et in t he Standard Event Status Enable Register will cause the ESB bit to be set in the Status Byte Reg ist er.

The Standard Event Status Regist er is r ead and c leared by the * ESR? comm and. The Standard Event Status Enable register is set by the *ESE <nrf> command and read by the *ESE? command.

It is a bit field where each bit has the following signif icanc e.

Bit 5 - Command Err or. Set when a syntax type error is detected in a command from the bus.

Bit 4 - Execution Error. Set when an error is encountered while attempting to execute a

completely parsed command. The appropriate error number will be reported in the

Bit 3 - Verify Timeout Error. Set when a parameter is set with 'verify' specified and the value is

Bit 2 - Query Error. Set when a query error occurs. The appropriate er ror number will be

Execution Error Register

This register contains a number r epresenting the last error encountered over the current interface. The Execution Error Register is read and cleared using the ‘EER?’ command. On power up this register is set to 0 for all inter face instances.

Error messages have the following meaning:

100 The numerical value sent with the command was too big or too small. Includes negative

101 A recall of set up data has been requested but the store specified contains corrupted data.

This indicates either a hardware fault or a tem por ar y data corr upt ion which can be correct ed

200 Read Only: An attempt has been made to change t he inst r um ents settings from an interf ac e

Limit Event Status and Limit Event Status Enable Registers

These two registers are implemented as an addit ion t o t he I EEE Std.488.2. Their purpose is to inform the controller of entry to and/or exit from current or voltage limit conditions and the history of protection trip conditions since the last r ead.

Any bits set in the Limit Event Status Register which corresponds to bits s et in t he Limit Event Status Enable Register will cause the LIM1 bit to be set in the Status Byte Register .

Bit 7 -

Reserved for future use

Bit 6 -

Set when a fault trip has occurred which requires AC power OFF/ON to reset.

Bit 5 -

Set when an output sense trip has occurred

Bit 4 -

Set when an output over current trip has occurred

Bit 3 -

Set when an output over voltage trip has occurred

Bit 2 -

Set when output enters power limit (unregulated mode)

Bit 1 -

Set when output enters current limit (constant current mode)

Bit 0 -

Set when output enters voltage limit (constant voltage mode)

Bit 3 -

Not used.

corresponding bits are set in the Limit Event Status Enable register.

Status Byte Register

= 0

Service Request Enable Register †

= 0

Standard Event Status Register

= 128 (pon bit set)

Standard Event Status Enable Register †

= 0

Execution Error Register

= 0

Query Error Register

= 0

Parallel Poll Enable Register †

= 0

The Limit Event Status Register is read and cleared by the LSR1? comm and. The Limit Event Status Enable Register is set by the LSE1 <nrf> command and read by the LSE1? command.

Status Byte Register and Service Request Enable Register

These two registers are implemented as r equired by the IEEE Std. 488.2. Any bits set in the Status Byte Register which correspond to bits set in the Service Request Enable Register will cause the RQS/MSS bit to be set in the Status Byte Register, thus generating a Service Request on the bus.

The Status Byte Register is read either by the *STB? command, which will return MSS in bit 6, or by a Serial Poll which will return RQS in bit 6. The Service Request Enable register is set by the *SRE <nrf> command and read by the *SRE? command.

Bit 7 - Not used. Bit 6 - RQS/MSS. This bit, as defined by IEEE Std. 488.2, contains both the Requesting

Service message and the Master Status Summary message. RQS is returned in response to a Serial Poll and MSS is returned in response to the *STB? command.

Bit 5 -

Bit 4 - MAV. The Message Available Bit. This will be set when the instrument has a response

Bit 2 - Not used. Bit 1 - Not used. Bit 0 -

ESB. The Event Status Bit. This bit is set if any bits set in the Standard Event Status

message formatt ed and r eady to send to the controller. The bit will be cleared after the Response Message Terminator has been sent.

LIM1. This will be set if any bits in the Limit Event Stat us register are set and

Power on Settings

The following instrument status values are set at power on:

† Registers marked thus are s pecific to the GPIB section of the instr ument and are of limited use in an RS232 environment.

The instrument will be in local state with the keyboard active. The instrument parameters at power on are t he s am e as at last switch off with the exception of

the output status. By default this is always off at power on but the user m ay chang e t his to the same at power on as at switch off.

Status Model

Remote Command Form at

RS232 input to the instrument is buffered in a 256 byte input queue which is filled, under interrupt, in a manner transparent t o all other inst rument operations. The instrument will send XOFF when approximately 200 characters are in the queue. XON will be sent when approximately 100 free spaces become available in the queue after XO FF was sent. This queue contains raw (un-parsed) data which is taken, by the parser, as required. Commands (and queries) are executed in order and the parser will not start a new command until any previous command or query is complete. RS232 responses to c om m ands or queries are sent immediately; there is no output queue.

USB input conforms with USB 2.0 Full Speed. Commands must be sent as specified in the com m ands list and m us t be terminated with the

command terminator code 0AH (Line Feed, LF). Com m ands m ay be sent in groups with individual commands separated from each other by the code 3BH (;). The gr oup must be terminated with command terminator 0AH (Line Feed, LF) .

Responses from the instrument to the controller are sent as specified in the comm ands list . Each response is terminated by a CR) followed by 0AH (Line Feed, LF).

<RESPONSE MESSAGE TERMINATOR> which is 0DH (Carriage Return,

Remote Commands

<WHITE SPACE> is defined as character codes 00H to 20H inclusive. <WHITE SPACE> is ignored except in command identifiers. e.g. '*C LS' is not equivalent to '*CLS'.

The high bit of all characters is ignored. The commands are case insensitive.

GPIB Remote Command Formats

GPIB input to the instrument is buff er ed in a 256 byte input queue which is filled, under interrupt, in a manner transparent to all other instrument operations. The queue contains raw (un-parsed) data which is taken, by the parser, as required. Commands (and queries) are executed in order and the parser will not start a new command until any previous command or query is complete. There is no output queue which means that the res ponse formatter will wait, indefinitely if necessary, unt il the inst rument is addressed to talk and the complete response m essage has been sent, before the parser is allowed to start the next comm and in t he input queue.

Commands are sent as or more

<PROGRAM MESSAGE UNIT> elements separated by <PROGRAM MESSAGE UNIT SEPARATOR>

elements.

<PROGRAM MESSAGE UNIT> is any of the commands in the remote commands list.

<PROGRAM MESSAGE UNIT SEPARATOR> is the semi-colon character ';' (3BH).

<PROGRAM MESSAGES> are separated by <PROGRAM MESSAGE TERMINATOR> elements which may

be any of the following:

<PROGRAM MESSAGES> by the controller, each m ess age consisting of zero

NL The new line character (0AH) NL^END The new line character with the END message ^END The END message with the last character of the message Responses from the instrument to the controller are sent as

<RESPONSE MESSAGE> consists of one <RESPONSE MESSAGE UNIT> followed by a <RESPONSE MESSAGE TERMINATOR>

<RESPONSE MESSAGE TERMINATOR> is the new line character with the END message NL^END.

<RESPONSE MESSAGES>. A

<rmt>

1 are all accepted as the

consistent with the use then rounded up to obtain the value of the comm and.

<nr1>

A number with no fractional part, i.e. an integer.

Each query produces a specific <RESPONSE MESSAGE> which is listed along with the command in the remote commands list.

<WHITE SPACE> is ignored except in command identifiers. e.g. '*C LS' is not equivalent to '*CLS'. <WHITE SPACE> is defined as character codes 00H to 20H inclusive with the exception of the NL

character (0AH). The high bit of all characters is ignored. The commands are case insensitive.

Command List

This section lists all commands and queries implemented in this instrument. The commands are listed in alphabetical order within the function groups.

Note that there are no dependent parameter s , coupled paramet ers, overlapping commands, expression program data elements or compound command program headers; each command is completely executed before the next command is started. All commands are sequential and the operation complete message is generat ed im m ediat ely after execution in all cases.

The following nomenclature is used:

<nrf>

A number in any format. e.g. 12, 12·00, 1·2e1 and 120enumber 12. Any number, when received, is converted to the required precision

<nr2> A number in fixed point format e.g. 11·52, 0·78 etc.

Instrument Specific Commands

For commands specified as 'WITH VERIFY' the operation is com pleted when the paramet er being adjusted reaches the requir ed value to within ±5% or ± 10 counts, whichever is the gr eater. If the value fails to settle within these limits within 5 seconds then the Verify Timeout bit (bit 3) is set in the Standard Event Status Register and the operation is completed at the end of t he timeout period.

The Operation Complete bit (bit 0) in the Standard Event Status Register is only ever set by the *OPC command. The *OPC (or the *OPC?) com m and can be us ed for device synchronisation due to the sequential nature of r em ote operations.

V1 <nrf> Set the output to <nrf> Volts. V1V <nrf> Set the output to <nrf > Volts with verif y. OVP1 <nrf> Set the output over voltage protection trip point to <nrf > Volt s. I1 <nrf> Set the output current limit to < nr f> Amps. OCP1 <nrf> Set the output over curr ent protection trip point to <nrf> Am ps. DAMPING1 <nrf> Set the current meter measurement averaging ( I

following meaning: 0=OFF, 1=ON. V1? Return the set voltage – response is V1 <nr2>< r mt> where <nr2> is in Volts. I1? Return the set current limit – r esponse is I1 <nr2><rmt> where <nr2> is in

Amps. OVP1? Return the voltage trip setting – response is VP1 <nr2><rmt> where <nr2>

is in Volts. OCP1? Return the current trip setting – response is CP1 <nr2><rm t > where <nr 2>

is in Amps.

) where <nrf> has the

AVG

byte register.

of the sequential nature of all operations.

V1O? Retur n the output readback voltage – response is <nr2> V< r m t> where

<nr2> is in Volts.

I1O? Return the output readback current – response is <nr2>A<rm t> where

<nr2> is in Amps. DELTAV1 <nrf> Set the output voltage step size to <nrf> Volts. DELTAI1 <nrf> Set the output current step size to <nrf> Amps . DELTAV1? Return the output voltage step size – response is DELTAV1 <nr2><rm t >

where <nr2> is in Volts. DELTAI1? Return the output current step size – response is DELTAI1 < nr2><rmt>

where <nr2> is in Amps. INCV1 Increm ent the output voltage by step size. INCV1V Increment the output voltage by step size with veri fy. DECV1 Decrement the output voltage by step size. DECV1V Decrement output voltage by step size with verify. INCI1 Increment the output curr ent limit by step s ize. DECI1 Decrement the output current limit by step size. OP1 <nrf> Set output on/off where <nrf> has the following meaning: 0=OFF, 1=ON. OP1? Returns output on/off status.

The response is <nr1><rmt> where 1 = O N, 0 = O FF.

OPALL <nrf> Set all outputs on/off where <nrf> has the following meaning: 0=OFF,

1=ON. In this instrument it has the same action as OP1 <nrf>.

SENSE1 <nrf> Set output sense mode where <nrf> has the following meaning: 0=local,

1=remote.

SAV1 <nrf> Save the current PSU set up to the set-up stor e specified by <nrf>

where <nrf> can be 0-9.

RCL1 <nrf> Recall a set up for the PSU from the set-up store specified by <nrf>

where <nrf> can be 0-9.

System and Status Commands

*CLS Clear Status. Clears the Status structure: this indirectly clears the status

*ESE <nrf> Set Event Status Enable Register to the value <nrf> *ESE? Report value of Event Status Enable Register *ESR? Query and clear the Event Status Register. The response format is

<nr1><rmt>. See Status Reporting section for details of the response.

*IST?

*OPC

Returns ist local message as defined by IEEE Std. 488.2. The syntax of the response is 0<rmt>, if the local message is false, or 1<rmt> , if the local message is true.

Sets the Operation Complete bit (bit 0) in the Standard Event Status Register. This will happen immediately the command is executed because

*OPC? Query Operation Complete status. The response is always 1<rmt> and will

be available immediately the command is executed because all commands are sequential.

*STB?

Report the value of the Status byte. Response is <nr1>.

QER?

Query and clear Query Error Register. The response format is nr1<rmt>

software installed.

*TST?

The PSU has no self-test capability and the response is always 0 <rmt>.

instrument.

unit

only.

PRE <nrf> Set the Parallel Poll Enable Register to the value <nrf>. PRE? Returns the value in the Parallel Poll Enable Register in <nr1> numeric

format.

The syntax of the response is <nr1><rmt > *SRE <nrf> Sets the Service Request Enable Register to <nrf > *SRE? Report the value in the Service Request Enable Register. Response is

<nr1>.

*WAI Wait for Operation Complete true. This command does nothing because all

operations are sequential. *RST

TRIPRST Attempt to clear all trip conditions. LOCAL G o t o local. IFLOCK Request Instrument ‘lock’. This command requests exclusive access control

IFLOCK? Query the status of the inter face ‘lock’. The return value is ‘1’ if the lock is

IFUNLOCK Release the ‘lock’ if possible. Returns ‘0’ if successful. If this com m and is

EER? Query and clear the Execution Error Register. The response format is

Resets the instrument to the f act ory default settings − with the exception of

all remote interface settings. See Factory Default Settings section.

of the instrument. The response is ‘1’ is successful or ‘-1’ if the lock is un

available either because it is already in use or the user has disabled this

interface from taking control using the web interface

owned by the requesting interface instance; ‘0’ if there is no active lock or ‘-

1’ if the lock is unavailable either because it is in use by another interface or

the user has disabled the interface from taking control via the web interface.

unsuccessful ‘-1’ is returned, 200 is placed in the Execution Error Register

and bit 4 of the Event Status Register is set indicating that you do not have

the authority to release the lock.

<nr1><rmt>. See Error Reporting section for details of the response. LSR1? Query and clear the Limit Status Reg ist er . The response format is

<nr1><rmt>. See Status Reporting section for det ails of the response. LSE1 <nrf> Set t he Lim it St atus Enable Register to <nrf> LSE1? Returns the value in the value in the Limit Status Enable register. Response

<nr1>.

Miscellaneous Commands

*IDN? Returns the instrument identification. The exact response is determined by

the instrument configur ation and is of the form <NAME>,<model>, 0,

<version><rmt> where <NAME> is the manufacturer 's name, <model>

defines the type of instrument and < version> is t he revision level of the

*TRG T h e PSU has no trigger capability. The comm and is ig nored in this

ADDRESS? Returns the bus Address <nr1>. This number can be used to identify the

CONFIG? Returns the Instrument Conf iguration. This is always ‘1’ as single output

Calibration Specific Commands

See Service Manual for details of calibration specific commands.

Note: The use of ‘1’ in many of the commands (e.g . V1 < nr f>, I1O?) is to keep the com mands entirely compatible with those for multi-output TTi programmable power supplies. ‘1’ refers to ‘Output 1’ which, for this power supply, is the only output; a dual output supply, for example, would have a duplicate set of commands V2 <nrf>, I 2O ?, etc.

Maintenance

The Manufacturers or their ag ents overseas will provide a repair service for any unit developing a fault. Where owners wish to undertake their own maintenance work, this should only be done by skilled personnel in conjunction with the service manual which may be purchased directly from the Manufacturers or their agents overseas.

Fuse

The correct fuse type is:

15 Amp 250V HBC time-lag, 1¼” x ¼”

Make sure that only fuses of the required rated current and specified type are used for replacement. The use of makeshift fuses and the short-circuiting of fuse-holders is prohibited.

To replace the fuse, first disconnect the instrument from the AC supply. Remove the 6 cover securing screws and lift off the cover. Replace the fuse with one of the correct t ype and refit the cover.

Note that the main function of the fuse is to make the instrument safe and limit damage in the event of failure of one of the switching devices. If a fuse fails it is t her efore very likely that the replacement will also blow, becaus e t he supply has developed a fault; in such circumstances the instrument will need to be returned to the manuf ac t ur er for service.

Cleaning

If the instrument r equires cleaning use a cloth that is only lightly dampened with water or a mild detergent.

WARNING! TO AVOID ELECTRIC SHOCK, OR DAMAGE TO THE INSTRUMENT, NEVER ALLOW WATER TO GET INSIDE THE CASE. TO AVOID DAMAGE TO THE CASE NEVER CLEAN WITH SOLVENTS.

Web link

For the latest version of this instruct ion m anual, I VI dr iver and any applicable firm ware updates go to http://www.tti-test.com/go/qsx .

Ltd

)

Thurlby Thandar Instruments

Glebe Road • Huntingdon • Cambridgeshire • PE29 7DR • England (United Kingdom

Telephone: +44 (0)1480 412451 • Fax: +44 (0)1480 450409

International web site:

www

.aimtti.com • UK web site:

www

.aimtti.co.uk

Email: info@aimtti.com

Aim Instruments and Thurlby Thandar Instruments Book Part No. 48511-1400 Issue 8

Thurlby Thandar Instruments QPX1200 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

OUTPUT SPECIFICATI ONS

METER SPECIFICATIONS

LOGIC CONTROL INPUT and OUTPUT

ANALOG REMOTE CONTROL and MONITORING

KEYBOARD & ROTARY CONTRO L

INTERFACES

GENERAL

Emissions

Immunity

Cautions

Mains Operating Voltage

Mains Lead

Mounting

Ventilation

Front Panel Connec tions

Rear Panel Connections

Output Terminals

Logic Input

Logic Output

Description

RS232

GPIB – Factory Option

Switching On, Output On/Off

Keypad

Jog Control

Display

Set Voltage

Set Current Limit

Instantaneous Current Output

Output Power (V x A)

Calculated Load Impedance (V/A)

Current Measurement Averaging

Connection to the Load

Remote Sensing

Sense Miswiring Trip

Series or Parallel Connection with Other Outputs

Over-Voltage Protection

Over-Current Protection

Output Protection

Temperature Trip and Other Faults

Logic Control Input and Output

Analogue Monitor

Store Settings

Deleting Stored Settings

Recall Settings

Extra Functions

Factory Default Settings

Bus and Address Selection

Interface Locking

Remote/Local Operation

RS232 Interface

RS232 Interface Connector

RS232 Connections

RS232 Character Set

USB Interface

LAN Interface

LAN Connection

LAN Status Indic ation

LAN Identify

Web Server; Configuration Password Protecti on

ICMP Ping Server

VXI-11 Discovery Protocol

XML Identification Document URL

TCP Sockets

GPIB Subsets

Query Error Register - GPIB IEEE Std. 488.2 Error Handl ing

GPIB Parallel Poll

St andard Ev ent Status and Standard Event St at us Enabl e Regist ers

Execution Error Register

Limit Event Status and Limit Event Status Enable Registers

Status Byte Register and Service Request Enable Register

Power on Settings

Status Model

Instrument Specific Commands

System and Status Commands

*IST?

PRE <nrf> Set the Parallel Poll Enable Register to the value <nrf>. PRE? Returns the value in the Parallel Poll Enable Register in <nr1> numeric