BK Precision 9120, 9121, 9122 Instruction Manual

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Model 9120, 9121 & 9122

Instruction Manual

SINGLE OUTPUT PROGRAMMABLE DC POWER SUPPLY

Table of contents

General Information ……………………………………………. 3 Features …………………………………………………..……… 5

Local Mode Operation ………………….……………………….. 7

Front panel description ……………………………………………. 7 Memory key ………………… ……………………………………. 7 Storing states in front panel mode ………………………………… 10 Recall key …………………………………………………………. 12 Recalling states in front panel mode ……………………………… 14 Limit key ………………………………………………………….. 15 Modes of operation ……………………………………………….. 16 Constant current operation ………………………………………... 18 Constant voltage operation ………………………………………. .. 20 On / Off key ……………………………………………………….. 22 Remote / Local key ………………………………………………... 23 Errors / Calibrate key …………………………………………… … 25

Calibration Overview ……………………………………………. 28

Calibration security code ……………………………………... ... 28

Unsecure procedure for calibration …………………………….… 29 Hardware unsecure procedure for calibration ……………………. 32 Calibration Procedure …………………………………………… 34 Voltage Calibr ation Procedure ……………………………………. 35 Volt Zero Scale Calibration ……………………………………….. 35 Volt Full Gain Calibration ………………………………………... 36 OVP Calibration …………………………………………………… 37 Current Calibration Procedure …………………………………….. 38 Current Zero Scale Calibration ……………………………………. 38 Current Full Gain Calibration …………………………………….. 39

OVP / Secure key ………………………………………………….. 41 Programming OVP in front panel mode …………………………. 44 Clearing OVP condition …………………………………………… 46

Rear panel description ………………………………………… …… 50

Remote Interface ……………………………………..………….. 51 SCPI Commands …………………………………………………. 52 SCPI Commands Overview ………………………………………. 54 DISPlay Subsystem ……………………………………………….. 54

Table of contents

OUTPut Subsystem ………………………………………………… 55 SYSTem Subsystem ……………………………………………….. 55 SOURce Subsystem ……………………………………………….. 56 MEASure Subsystem ………………………………………………. 62 TRIGger Subsystem ………………………………………………… 63

Non_SCPI commands ………………………………………………. 67 IEEE 488.2 commands ……………………………………………... 68

SCPI Status Registers ……………………………………………….. 70

Error Messages …………………………………………………… 74 Command Errors …………………………………………………… 74 Execution Errors …………………………………………………… 76 Device-specific Errors ……………………………………………... 76 Self-test Errors …………………………………………………….. 77 Calibration Errors …………………………………………………. 79

Technical Specifications ……………………………………….… 82 Supplemental Characteristics ……………………………………… 86 Programming Ranges ………………………………………………. 88 Reset Values ………………………………………………………... 89 Interface Cable ……………………………………………………… 90

Warranty Information ……………………………………….… 91 Service Information ………………………………………….… 93

General Information

Single output programmable DC power suppl ies.

Output voltage is: 0 to 30.0 V for Model 912 0

0 to 20.0 V for Model 912 1 0 to 60.0 V for Model 9122

Output current is: 0 to 3.00 A for Model 9120

0 to 5.00 A for Model 9121 0 to 2.50 A for Model 9122

The power supply can be locally or remote controlled. Interfaces: RS232 (Standard)

The commands available in remote interface mode are

• SCPI (Standard Commands for Programmable Instruments) commands

(SCPI 99 standard)

Features

• Constant Voltage / Constant C urrent modes of operation

This power supply can operate in either constant voltage or constant current modes. The passing from one mode of operation to another is automatic.

The active mode of operation is indicated using two indicators: CV – constant voltage mode of operation CC – constant current mode of operation

• Overvoltage protection

Overvoltage protection circuit can be locally or remote activated.

When it is active, ovp indicator is displayed.

• Output on / off

When output off, output voltage is 0 V.

This permits a zero output voltage without switching off the power supply.

• 100 operating states storage

States are identified by location number and name.

Stored parameters are: voltage limit, voltage step, overvoltage protection level, state of overvoltage protection circuit, current limit, current step, voltage trigger value, current trigger value, trigger delay value, trigger source, stored state name, state of display, output state.

After power on, state 0, named power_up will become the current operating state.

• error messages

Errors are stored in a 20 locations FIFO (first in first out) queue.

They can be read in local mode (error number returned) or in remote operation mode (error number and definition returned).

Every error is announced by a beep and the err indicator.

Local mode operation

Front panel keys description

Memory key

Note: Memory location 00 is the “Power-up” state. When the unit is powered

up, the power supply will set itself to the settings stored in location 00.

Note: If you press the Recall button while turning the power on, the power supply will power up using memory location 01 parameters.

This button is used to store power supply’s current operating state in nonvolatile memory. Using this function all operating parameters are saved so they can be recalled. You can store 100 differe nt operating states in the non-volatile memory.

By pressing Memory key, you enter in Memory menu. By turning the knob following options will be displayed:

Store State

Name State

Exit

Options are selected by pressing Memory key when the desired option is displayed.

Memory menu overview

Store State

Store State option will store the current operating state without setting a name for this state. The state will be identified using location number in non-volatile memory and the default name. By pressing Memory key, state number and state name are displayed in ascending order by turning the knob.

In this menu, Exit option is available, too. In this case, you leave the store operation mode, without changing anything. No Change message will be displayed and the power supply returns to the previous state (the state before entering Memory menu).

The states are scrolled using the knob. A location is selected by pressing Memory key. If the location you choose is already written, it is overwritten (without an y warning) with the current state parameters, but the name (the set one or the default one remains unchanged). Done message will be displayed.

Name State

Name State option allows you to set a name for the current state (you can also change a name set before). The state name can have up to 10 charatcters. The default name is 10 blank characters.

By pressing Memory key, state number of non-volatile memory locations is displayed in ascending order by turning the knob.

In this menu Exit option is available, too. In this case, you leave the store operation mode, without changing anything. No Change message will be displayed and the power supply returns to the previous state (the state before entering Memory menu).

The states are scrolled using the knob.

By pressing Memory key again, state name can be set.

Important note!

A state name must be set here, or the state will not be saved.

When setting the name, selected digit has the cursor underneath it. Characters of the name are selected by rotating the knob. When desired ASCII character is displayed, you can pass to another digit selection using > < cursor position keys. When the name is set, you press Memory again and the current state is stored in the selected location of the non-volatile memory. Done message wil l be displayed.

Important note! Store State option will store the parameters of current operation state and will

not set a name for the stored state. NameState option will set a name for the the state to be saved.

Exit

Exit option allows you to leave th e store operation mode, without changing anything. No Change message will be displayed and the power supply returns to the previous state (the state before entering Memory menu).

Important note! If you enter in the Memory menu and no action takes place for approx. 20 seconds, the power supply leaves the Memory menu. No Change message is displayed and the power supply returns to the previous state (the state before entering Memory menu).

Storing states in front panel mode

To store an operating state in front panel mode you must follow the steps described bellow:

1. Set the power supply in the desired operating state

Voltage step, current step, voltage trigger value, current trigger value, trigger delay value, trigger source and state of display parameters can be set only over

the remote interface, using SCPI commands (for more details, see SCPI Commands section)

The rest of the parameters can be set both from the front panel or over the remote interface.

2. Enter the Memory menu

By pressing Memory key, you enter Memory menu. By turning the knob, following options are displayed:

Store State

Name State

Exit

Options are selected by pressing Memory key again.

3. Select StoreState option

When Store State or Name State options are selected, state number and state name (if available) of non-volatile memory locations are displayed in ascending order, by turning the knob.

If Store State option is selected, the stored operating state has the default name, if none set before.

Store State option will store the parameters of current operation state and will not set a name for the stored state. The saving action is realized by pressing Memory key. After that, Done message will be displayed.

and the power supply returns to normal mode.

4. Select Name State option In order to select this option , Memory key must be pressed again. NameState option will set a name for the the state to be saved.

The saving action is realized by pressing Memory key. After that, Done message will be displayed.

Important note! The power supply allows 100 states to be stored. When shipped, the power supply has power_up state stored and all the other locations are empty.

The stored states are kept in a non -volatile memory, so they won’t be lost when the power supply is turned off.

A state location can be overwritten without any notification from the power supply.

Done

Recall key

This key is used to recall an operating state from the storage locations in nonvolatile memory. You can recall any operating state from 100 different operating states stored in the non-volatile memory. The recalled state becomes the current operating state.

By pressing Recall key, you enter in Recall menu. By turning the knob, following options will be displayed:

00: power_up

01:

02: Test_mode

etc. (all 100 operating states are displayed)

Exit

Reset

Options are selected by pressing Recall key when the desired option is displayed. Recalling action is terminated by pressing Recall key. After that, Done message will be displayed.

Recall menu overview

01: State 1

When a state option is selected, the stored state recalled becomes the current operating state of the power supply.

Recalled parameters are: voltage limit, voltage step, overvoltage protection level, state of overvoltage protection circuit, current limit, current step, voltage trigger value, current trigger value, trigger delay value, trigger source, stored state name, state of display, output state.

Exit

Exit option allows you to leave the Recall menu, without changing anything. No Change message will be displayed and the power supply returns to the previous state (the state before entering Recall menu).

Reset

Reset option allows you to reset the power supply without switching off (for more details see Reset Values section) .

00: power_up

After power up, the power supply recalls state 0.

When delivered, power_up state has the following parameters:

= 1 V

lim

= maximum available current value (see Programing ranges

lim

table, in the Techincal Specifications section)

OVP trip level = maximum programmable value (see Programing ranges table, in the Techincal Specifications section)

Output state on

The rest of the parameters have the default value after reset. (see Reset values table, in the Techincal Specifications section)

For this operating state, Name State option is not available (so the state name cannot be changed ), but Store State option is available (so the user can save the desired state for power up) .

Important note! If you enter Recall menu and no action takes place for approx. 20 seconds, the power supply leaves the Recall menu. No Change message is displayed and the power supply returns to the previous state (the state before entering Recall menu).

Recalling states in front panel mode

To recall an operating state in front panel mode, you must follow the steps described bellow:

1. Enter the Recall menu

By pressing Recall key, you enter the Recall menu. By turning the knob, following options are displayed:

01: State 1

02: Test_mode

etc. (all 100 operating states are displayed)

Exit

Reset

2. Select the operating state

By using < > keys and turning the knob all operating states stored in nonvolatile memory are displayed. An operating state is selected by pressing

Recall key when desired state is displayed.

3. Recall the operating state

When Recall key is pressed, the selected operating state becomes the current operating state of the power supply, after Done message is displayed.

Limit key

The power supply works in 2 modes:

ØØ Limit mode ØØ Normal mode

In limit mode limit values of voltage and current are displayed. These are the programmed values (from the front panel or over the remote interface).

Limit key is used to get the power supply to limit mode. In this mode, lmt indicator and limit values for voltage and current will be displayed.

In limit mode, limit values can be adjusted by turning the knob. To adjust values in limit mode, > < keys must be used to select the digit you want to adjust. The selected digit has the cursor underneath it. To increase / decrease value of digit, knob must be turned.

After setting the limit values, by pressing Limit key, the power supply returns to normal mode. It also returns to normal mode after several seconds (display time-out) with no action.

In normal mode, voltage and current values measure d at the output terminals of the power supply are displayed.

When you turn on the power supply, the cursor is placed underneath the voltage value (units digit). To pass from voltage value to current value Volt/Amp key must be used. This key toggles between voltage value and current value.

Modes of operation

Depending on the application, the power supply can be used as a constant current source or as a constant voltage source.

In order to understand constant current and constant voltage operation, a numeric example will be used.

out

Let’s consider a resistor connected to the output terminals of the power supply (R resistor). Limit (programmed) values are:

=5V

lim

=2A

lim

and I

out

are the voltage and current values measured at the output

out

terminals of the power supply.

Depending on the resistor value, the power supply will pass from one mode of operation to another

R (Ù) U

(V) I

out

(A) Mode of

out

operation

10 5 0.5 CV

5 5 1 CV 1 2 2 CC

In constant voltage mode, programmed voltage value is equal with the voltage value measured at the output terminals of the power supply. (U

out

= U

lim

). Using Ohm’s law, depending on the resistor’s value, output current value can be calculated and it is smaller than current limit value (see first and second rows of the table).

The power supply will remain in CV operation as long as the limit current value is greater than output current value.

When the resistor’s value decreases so the output current value becomes equal to the current limit value, power supply will go to constant current operation (see third row of the table) .

If the resistor value is R = 1 Ù, for U

= 5V, using Ohm’s law the output

out

current is 5A. But this value is greater than current limit value, so the power supply limits the output current to the limit programmed value. That is why in the third row of the table I

= 2 A. In this case, U

out

is changed, too. Using

out

Ohm’s law again, the output voltage is calculated using output current value and the resistor value, so it is 2 V.

So the power supply will go to constant current operation when the output current value becomes equal or greater than the limit value.

When the output current value becomes smaller than the limit value (by changing resistor’s value), the power supply will go back to constant voltage operation.

In conclusion:

CV: U

out

= U

lim

and I

out

< I

lim

CC: U

out

< U

lim

and I

out

= I

lim

The following section will explain how to get the power supply in constant current operation mode and in constant voltage operation mode.

Constant current operation

In constant current operation, current values in limit mode and normal mode are the same, but voltage values are not.

To set the power supply in constant current operation, you must follow the steps described bellow:

1. Select the limit values for voltage and current parameters (U

), depending on the application

lim

2. Calculate resistor’s value R

load

Using Ohm’s law, calculate the resistor’s value that allows the power supply to go in constant current mode of operation.

3. Turn on the power supply and set limit mode operation

Press Limit key to set limit mode. Now the power supply displays limit values for voltage and current. lmt indicator is displayed, too. (it will be displayed until you go to normal mode).

4. Set voltage and current limit values

Limit values must be chosen so the following conditions are respected:

U I

lim

> I

lim

· R

,so U

load

lim

< U

< I

out

Voltage and current limit values are set using:

Volt / Amp key to select current value, > < keys to select the digit to adjust (selected digit has cursor underneath it) knob to set the digit to desired value

5. Set normal mode operation

You can set normal mode operation by pressing Limit key or let the display time-out (after several seconds with no action, power supply returns to normal mode operation).

6. Disable the output of the power supply By pressing On / Off key, the output of the power supply can be disabled.

7. Connect R

resistor is connected between (-) and (+) terminals of the power supply.

load

resist or to the output terminals

load

lim

and

8. Enable the output of the power supply

By pressing On / Off key, you enable the output. Power supply goes to normal mode operation and CC indicator will be displayed. In this case constant current operation is active. If CV indicator will be displayed, you must set a higher value for voltage limit.

Important note!

By turning the knob, voltage and current limit values can be adjusted. The adjustion of the voltage limit value can be seen only in limit mode. The adjustion of the current limit value can be seen in both limit mode and normal mode.

Important note!

Constant current operation can be used depending on the application. It is very useful to protect the circuitry connected to the power supply from accidently increases of current value.

Constant voltage operation

In constant voltage operation, voltage values in limit mode and normal mode are the same, but current val ues are not

To set the power supply in constant voltage operation, you must follow the steps described bellow:

1. Select the limit values for voltage and current parameters (U

), depending on the application

lim

2. Calculate resistor’s value R

load

Using Ohm’s law, calculate the resistor’s value that allows the power supply to go in constant current mode of operation.

3. Turn on the power supply and set limit mode operation

Press Limit key to set limit mode. Now the power supply displays limit values for voltage and current. lmt indicator is displayed, too. (it will be displayed until you go to normal mode).

4. Set voltage and current limit values

Limit values must be chosen so the following conditions are respected:

U I

lim

< I

lim

· R

load

,so

lim

< U

< I

out

lim

and

Voltage and current limit values are set using:

Volt / Amp key to select current value, > < keys to select the digit to adjust (selected digit has cursor underneath it) knob to set the digit to desired value

5. Set normal mode operation

You can set normal mode operation by pressing Limit key or let the display time-out (after several seconds with no action, power supply returns to normal mode operation).

6. Disable the output of the power supply By pressing On / Off key, the output of the power supply can be disabled.

7. Connect R

resistor is connected between (-) and (+) terminals of the power supply.

load

resistor to the output terminals

load

8. Enable the output of the power supply

By pressing On / Off key, you enable the output. Power supply goes to normal mode operation and CV indicator will be displayed. In this case constant voltage operation is active. If CC indicator will be displayed, you must set a higher value for current limit.

Important note!

By turning the knob, voltage and current limit values can be adjusted. The adjustion of the current limit value can be seen only in limit mode. The adjustion of the voltage limit value can be seen in both limit mode and normal mode.

On / Off key

On / Of f key is used to enable / disable the output of the power supply from the

front panel. By pressing On / Off key, you alternate these two states: output on / output off.

When the output is off, power supply displays:

Output off

The indicators according to power supply’s state will also be displayed (e.g.: ovp, err indicators).

When output off, output voltage is 0 V. So this command permits a zero output voltage without switching off the power supply.

When output off, knob is disabled, to prevent the unwanted ch anges in voltage and current values. The keys from the front panel are not disabled. You can also go to limit mode and set limit values for voltage and current. In this case both lmt and off indicators will be displayed.

When output off, by press ing On / Off key,the output is enabled. The power supply will go to normal mode of operation (voltage and current measured values are displayed) or to limit mode of operation (voltage and current limit values are displayed), depending on the state the power supply was before disabling the output.

The output state of the power supply is one of the parameters stored in nonvolatile memory for each state .

Remote / Local key

This key has a double function, depending on the state of the power supply (remote mode or local mode).

Local Mode function

While in local mode of operation, Remote / Local key has a double function, depending on the state of the power supply.

If the power supply is in calibrating mode, Remote / Local key is used to leave the calibrating mode and return to normal mode of operation (for more details,

see Calibration Overview section)

When in local mode of operation, by pressing Remote / Local key, RS 232 interface parameters are displayed:

Available settings for RS232 interface:

♦ Baud rate: 1200, 2400, 4800, 9600 (factory setting: 9600) ♦ Parity and data bits: None – 8 data bits (factory setting)

Odd – 7 data bits Even – 7 data bits

♦ Number of start bits: 1 bit (cannot be changed) ♦ Number of stop bits: 1 bits (cannot be changed)

Set RS – 232 remote interface parameters

1. Select RS – 232 interface

Press Remote / Local key. Following message will be displayed:

RS - 232

Press Remote / Local key again. Baud rate settings will be displayed.

2. Select baud rate

By turning the knob, you will view available baud rate. When desired baud rate is displayed, press Remote / Local key. Parity settings will be displayed.

Select parity

By turning the knob, you will view available parities. When desired parity is displayed, press Remote / Local key.

These settings are saved in non-volatile memory, so they don’t change when you turn of the power supply.

If you didn’t change anything of the previous set parameters, the power supply will display No Change message. If you did change a single parameter from the previous set parameters, Saved message will be displayed. After one of these messages is displayed for several seconds, you return to the previous state.

Important note! If you enter in the Remote / Local submenu and no action takes place for approx. 20 seconds, the power supply will leave this submenu. No Change message is displayed and the power supply returns to the previous state (the state before entering this submenu).

Important note!

While in local mode, if by pressing Remote / Local key

message will be displayed, it means that the RS-232 remote interface parameters cannot be read from the non-volatile memory. The power supply must be turned off and then turned on. If this message is displayed again while pres sing Remote / Local key in local mode, the power supply must be delivered to B&K Precision for service.

Remote interface function

When in remote interface mode of operation, rmt indicator will be displayed. In this case, all front panel keys are disabled, except Remote / Local key, which is active. This allows you to put the power supply in local mode of operation, so all front panel keys become active.

I / O Error

Errors / Calibrate key

This key has a double function: errors related in normal mode (see this section) and calibration related in calibration mode (see calibration section).

There are 2 types of errors: user defined errors and errors defined by SCPI 1999 standard.

Every time an error is generated, a beep will be generated by the power supply and err indicator will be displayed.

Generated errors are saved in an error queue, in FIFO (first in – first out) order. If more than 20 errors are generated, the last error is overwritten with –350 error (queue overflow error) and no more errors are saved.

While in remote mode (rmt indicator is displayed), errors are erased from the queue as you read them.

By pressing Errors / Calibrate key, you enter Errors / Calibrate menu. By turning the knob, following options are displayed:

Errors

Cal String

Exit

Options are selected by pressing Errors / Calibrate key when the desired option is displayed.

Errors

Errors option allows you to view the generated errors. If you press Errors / Calibrate key again, by turning the knob you can see all generated errors. Error’s code will be displayed. When all errors were viewed, if continue to turn the knob, they will be displayed again.

After you viewed all errors, you press Errors / Calibrate key again. The power supply will erase all the errors from the error queue and Errors Erased message will be displayed.

After several seconds the power supply will go back to normal mode. The err indicator will not be displayed anymore.

If there are no errors in the queue and you select Errors option in order to view the errors, the power supply will display:

No Errors

And then it will return to normal mode.

There are 3 ways of erasing the error queue:

♦ By turning off and then turning on the power supply ♦ By pressing Errors / Calibrate key after errors are displayed, in local

mode

♦ By reading errors, in remote operation.

Important note! If you let the display time out, the power supply will go back to normal mode, without erasing the error queue.

Cal String

The power supply allows you to store a calibration message. It may contain last calibration date, the date when the next calibration must be done or the name and the phone number of the person to contact for a new calibration.

This message can have up to 40 characters. It can be set only remote interface and it is saved in non-volatile memory.

When delivered, the power supply has the following calibration string set: “CALIBRATION DATE: MMM/DD/YYYY” (for example: CALIBRATION DATE: Feb/11/2005)

Cal String option allows you to view the calibration string.

If you press Errors / Calibrate key when Cal String option is displayed, the calibration message will be displayed. To scroll through the calibration message, you must press < key. To increase the scrolling speed, you must press > key. To decrease scrolling speed, you must press < key.

Exit

Exit option allows you to leave this menu, without changing anything. Exiting message will be displayed and the power supply returns to the

previous state (the state before entering this menu).

Important note! If you enter in the Errors / Calibrate menu and no action takes place for approx. 20 seconds, the power supply leaves this menu. Exiting message is displayed and the power supply returns to the previous state (the state before entering Errors / Calibrate menu).

Calibration overview

Calibration is a procedure that ensures that the power supply will work properly, with parameters specified within Technical Specification section.

Before initiating the calibration procedure, the following conditions must be assured:

disconnect any loads connected to the power supply and turn it on

let the power supply turned on for 1 hour, with no loads connected before

you start the calibration procedure

calibration ambient temperature must be 25 0C

ambient relative humidity must be less then 80%.

Recommended calibration interval is 1 year.

Important note!

In order to perform the calibration procedure, a digital multimeter is needed. It must have the following characteristics: Voltage resolution: 0.1 mV Current resolution: 0.01 mA Acurracy: 0.01 %

Calibration security code

To prevent accidental or unauthorized calibration procedures, the power supply has a calibration security code. This security code is optional, so you may have it or not. The power supply will work properly in both cases.

Security code may contain numbers (0..9), small letters (a..z) and spaces (“ “). Any of these characters may be used as the first character in security code. Security code may contain up to 11 characters. But it is not necessary for you to use all 11 char acters for the security code. The security code is saved in non-volatile memory and it doesn’t change when you turn on or turn off the power supply.

When delivered, power supply has the following security code: 0000

In order to initiate the calibration procedure, first you must unsecure the power supply (if a security code is set).

Unsecure procedure for calibration

To unsecure the power supply, the next steps bust be followed:

1. Turn on the power supply in calibrating mode

To enter calibrating mode, you must turn on the power supply while pressing Errors / Calibrate key. You release the key after the long beep. After that, the power supply will display:

Calibrating Mode Secured

if the power supply is secured (if the power supply has a security code set). If this message is displayed, go to step 2.

or :

Calibrating Mode Unsecured

if the power supply is not secured (if the power supply has been turned off after the unsecure procedure). If the power supply is already unsecured, you can proceed with calibration (see

Calibration procedure section)

2. Enter security code

Press OVP / Secure key. The power supply will display:

Security code: _ _ _ _ _ _ _ _ _ _ _

Here you must enter the security code, using > < keys and knob. The selected digit has the cursor underneath it. If you set the digit to the desired value, you must press > key and go to the next digit, if you want.

After you entered the security code, press OVP / Secure key and if the security code is correct, the power supply will display:

Calibrating Mode Unsecured

From this moment you can proceed with calibration (see Calibration p rocedure section) or you can go back to normal mode operation. From now on, the power supply remains unsecured until you set a new secure code.

If the security code you entered is not correct, power supply will display:

Security code: invalid

for 1 second. 703 error (Invalid secure code) and a short beep will be generated. You can see the error in normal mode operation (by pressing Local key). After that power supply will display again:

Security code: _ _ _ _ _ _ _ _ _ _ _

and you must enter security code again , using < > keys and knob. If you don’t remember the correct security code, you may follow the hardware unsecure procedure (see Hardware unsecure procedure ).

Important Note! While in calibrating mode, before you unsecure the power supply, only Local, < > and Secure keys are active (all the rest are locked). The knob is also active. Local key can be used at any moment of unsecure procedure to leave

calibrating mode and go back to normal mode operation. Secure key is used in unsecure procedure of the power supply (allows you to enter and validate the secure code).

While in calibrating mode, after you unsecure the power supply, only Local,

Secure, < > and Calibrate keys are active. The knob is also active. Local key is used to leave calibrating mode and go back to normal mode

operation. Secure key is used to set a new security code (you may introduce a new security code and secure again the power supply).

Calibrate key is used to proceed with calibration.

Attention! Local key is active all the time while in calibrating mode and by pressing it the

power supply returns to normal mode. Leaving the unsecure procedure does not

change anything concerning the secure state of the power supply (secured or unsecured).

After you changed the security code or unsecured the power supply, you can go back to normal mode by pressing Local key. (You can come back to

calibrating mode only by turning off the power supply and starting it in calibrating mode).

But once you started the calibration procedure, it is recommended to finish it and to go back to normal mode by turning off and on the power supply.

Hardware unsecure procedure for calibration

This procedure may be used to unsecure the power supply if you forgot the security code.

To unsecure the power supply without using the security code, follow the next steps:

1. Turn off the power supply. Disconnect the power cord and all loads

connected to the power supply.

2. Remove power supply’s cover. Set J6 jumper for hardware unsecuring

mode.

J5 J6

Normal

unsecuring

3. Connect the power cord to the power supply. Turn on th e power supply in

calibrating mode.

4. Unsecure the power supply.

To unsecure the power supply you must press Secure key. Power supply will display:

Calibrating Mode Secured

Press again Secure key the power supply will display:

Security code: _ _ _ _ _ _ _ _ _ _

Here any security code may be introduced, since it is not verified by the power supply. Press again Secure key and you will unsecure the power supply. It will display:

Calibrating Mode Unsecured

Hardware

unsecuring

The power supply remains unsecured until you enter a new security code.

Important note!

Even if you are in calibrating mode, you cannot set a security code as long as the J6 jumper is in hardware unsecuring position.

5. Set J6 jumper for normal unsecuring mode.

Important note!

If you turn on the power supply in either normal mode or calibrating mode and

J6 jumper is in hardware unsecuring position, error 701 (Calibration security disabled by jumper) will be generated.

6. Turn off the power supply and reassemble it.

Calibration procedure

Before initiating the calibration procedure, the following conditions must be assured:

disconnect any loads connected to the power supply and turn it on

let the power supply turned on for 1 hour, with no loads connected before

you start the calibration procedure

calibration ambient temperature must be 25 0C

ambient relative humidity must be less then 80%.

On calibration procedure there are three parameters that must be calibrated: voltage, OVP and current.

You can leave the calibration procedure at any time by turning off the power supply or by pressing Local key. But once you started the calibration procedure, it is recommended to finish it and to go back to normal mode by turning off and then turning on the power supply. In order to be sure that the power supply will work properly in normal mode after you leave the calibration procedure, you must turn off the power supply.

Recommended calibration interval is 1 year.

Before calibrating the power supply you must unsecure it, if secured (see Calibration Overview section).

After you unsecured the power supply and you pressed Calibrate key, you go to Calibrate menu. By turning the knob next options are available:

1. Volt Zero Scale

2. Volt Full Gain

3. OVP

4. Curr Zero Scale

5. Curr Full Gain

Options are selected by pressing Calibrate key.

Important note!

In order to perform a correct calibration the calibration procedures from the Calibrate menu must be followed in the order they are displayed by the power supply.

Voltage Calibration Procedure

After you unsecured the power supply and you pressed Calibrate key, you entered calibrate mode.

Volt Zero Scale Calibration

1. Select Volt Zero Scale calibration procedure

In order to start voltage calibration procedure, you must select Volt Zero Scale option. The power supply will display:

You select this option by pressing Calibrate key. The power supply will display:

2. Initiate DAC calibration procedure

Connect a digital voltmeter to the output terminals of the power supply. After that, you must adjust DAC value displayed by the power supply until the voltmeter indicates the closest possible to 0.000 V value. For this, you use > < keys and the knob.

It is not necessary to disconnect the digital voltmeter, since you will need it later on calibration procedure!

3. Initiate ADC calibration procedure

Press Calibrate key. This will initiate ADC calibration procedure. The power supply will display:

After ADC calibration, power supply will return to Calibrate menu Volt Full Gain calibration procedure.

Calibrating Mode Volt Zero Scale

Volt Zero Scale DAC:1999

Volt Zero Scale ADC Calibrating

Volt Full Gain Calibration

1. Select Volt Full Gain calibration proce dure

In order to finish voltage calibration procedure, you must select Volt Full Gain option. The power supply will display:

You select this option by pressing Calibrate key. The power supply will display:

2. Initiate DAC calibration procedure Connect a digital voltmeter to the output terminals of the power supply. After that, you must adjust DAC value displayed by the power supply until the voltmeter indicates the correct voltage value, depending on the model of the power supply (see the tabl e bellow).

For this, you use > < keys and the knob

3. Initiate ADC calibration procedure Press Calibrate key. This will initiate ADC calibration procedure. The power supply will display:

After ADC calibration, power supply will return to Calibrate menu, OVP calibration procedure.

Calibrating Mode Volt Full Gain

Volt Full Gain DAC:31470

Power supply model Voltage value for

Volt Full Gain calibration 9120 16.3840 V 9121 16.3840 V 9122 32.7680 V

Volt Full Gain ADC Calibrating

OVP Calibration

While performing this calibration procedure, the power supply must have no loads connected to the output terminals.

1. Select OVP calibration procedure

In order to initiate OVP calibration procedure, you must select OVP option. The power supply will display:

You select this option by pressing Calibrate key. The power supply will displ ay:

Important note! This calibration procedure will take several minutes.

After OVP calibration, power supply will return to Calibrate menu, Current calibration procedure.

Calibrating Mode OVP

Calibrating OVP Please wait…

Current Calibration Procedure

Current calibration procedure must be permormed after Voltage calibration

procedure.

Current Zero Scale Calibration

While performing this calibration procedure, the power supply must have no loads connected to the output terminals.

1. Select Curr Zero Scale calibration procedure

In order to start current calibration procedure, you must select Curr Zero Scale option. The power supply will display:

2. Initiate DAC calibration procedure

You select this option by pressing Calibrate key. So Current Zero Scale calibration procedure will be initiated.

The power supply will display:

After a while, the power supply will display:

Important note! This calibration procedure will take several minutes.

Calibrating Mode Curr Zero Scale

Curr Zero Scale ADC:Calibrating

Curr Zero Scale DAC:Calibrating

After Current Zero Scale calibration procedure, power supply will return to Calibrate menu, Curr Full Gain calibration procedure.

Curr Full Gain Calibration

1. Select Curr Full Gain calibration procedure In order to finish current calibration procedure, you must select Curr Full

Gain option.

The power supply will displ ay:

You select this option by pressing Calibrate key. The power supply will display:

2. Initiate DAC calibration procedure In order to initiate Curr Full Gain calibration procedure, you must connect a digital ammeter to the output terminals of the power supply. If don’t connect a digital ammeter within 30 seconds, the power supply will display:

and it will return to Calibrate menu.

After you connected the digital ammeter, you must adjust DAC value displayed by the power supply until the ammeter indicates indicates the correct current value, depending on the model of the power supply (see the table bellow).

For this, you use > < keys and the knob

3. Initiate ADC calibration procedure

Press Calibrate key. This will initiate ADC calibration procedure. The power supply will display:

Calibrating Mode Curr Full Gain

Curr Full Gain Connect Ammeter

Calibrating Mode CC Not Set

Power supply model Current value for

Curr Full Gain calibration

9120 2.62144 A 9121 2.62144 A 9122 1.31072 A

Curr Full Gain ADC Calibrating

After ADC calibration, power supply will return to Calibrate menu.

In this moment, the calibration procedure is finished. By presing Local key, the power supply will return to local mode.

Important note! In order to be sure that the power supply will work properly in normal mode after you leave the calibration procedure, you must turn off the power supply.

OVP / Secure key

This key has a double function: OVP settings in normal mode operation and secure key in calibration mode operation (for the latter see Calibration section).

In this section OVP functions will be described.

OVP circuit prevents the output voltage from rising above a programmed voltage value. So the load connected to the output terminals is protected to overvoltage situations.

Overvoltage protection circuit is activated when output voltage value becomes equal or greater than the programmed trip level for overvoltage protection circuit.

OVP menu overview

By pressing OVP / Secure key, you enter OVP menu. Here, programmed OVP trip level will be displayed.

When you turn on the power supply, OVP trip level is OVP trip level value saved at power_up state (state 0). This value can be changed by the user (and saved in power_up state if wanted).

Here you can set desired OVP trip level, by using > < keys to select the digit you want to adjust (sel ected digit has the cursor underneath) and knob to set the digit to desired value.

The programming range for OVP trip level depends on the model of the power supply (see the table bellow):

Power supply

model

9120 1 V 33 V 9121 1 V 22 V 9122 1 V 63 V

The OVP trip level you set is programmed by pressing OVP / Secure key.

After that, you enter the OVP menu. By turning the knob, following options are displayed:

OVP min value OVP max value

OVP On

OVP Clear

OVP Off

Options are selected by pressing OVP / Secure key when the desired option is displayed.

OVP On

OVP On option enables overvoltage protection circuit. OVP trip level is the level value you programmed on Level option (after you first pressed OVP / Secure key).

If you want to keep the previously programmed trip level, you simply press OVP / Secure key, without changing anything.

If you enable the overvoltage protection circuit, when you return to normal mode, ovp indicator will be displayed.

OVP Off

OVP Off option makes OVP trip level equal to maximum availabale OVP value , no matter what what value is set in OVP menu (but the value from OVP menu does not change). For maximum available OVP value see the table above.

If you select OVP Off option, when you return to normal mode, ovp indicator will not be displayed anymore.

Important note!

When OVP On option is selected, OVP trip level is equal to the programmed level, shown in OVP menu. When OVP Off option is selected, OVP trip level is equal to the maximum available value for this parameter, depending on the model of the power supply (see the table above). In this case, the programmed OVP trip level, shown in OVP menu does not change!

Output Off

OVP Clear

OVP Clear option is used to clear to OVP condition (for more details about how you get back to normal mode after OVP level was tripped, see next section).

After you select the desired option, a message will be displayed. If you didn’t change anything of the previous set parameters, the power supply will display No Change message. If you did change a single parameter from the previous set parameters Done message will be displayed. After one of these messages is displayed for several seconds, you return to normal mode.

Important note! If you enter in the OVP menu and no action takes place for approx. 20 seconds, the power supp ly will leave the OVP menu. No Change message is displayed and the power supply returns to the previous state (the state before entering OVP menu).

If the output voltage value becomes equal or greater than OVP programmed level and the overvoltage protection circuit is enabled, the power supply will display:

Over Voltage

And the output voltage value will be 0 V (output is disabled).

There are three ways of clearing the OVP condition:

Ø By increasing OVP trip level and clearing the OVP condition Ø By decreasing the output voltage and clearing the OVP condition Ø By disabling OVP circuit and by clearing the OVP condition

Important note!

When you turn on the power supply, the overvoltage protection circuit is enabled and the OVP trip level is equal to the one saved in power_up state (factory setting: maximum available value ).

Programming overvoltage protection circuit in front panel mode

If you want to program an OVP trip level and to enable the overvoltage protection circuit using front panel keys, follow the next st eps:

1. Turn on the power supply

When you turn on the power supply, the overvoltage protection circuit is enabled and OVP trip level is set to maximum available value for OVP parameter, depending on the model of the power supply (see table in the prevous sec tion).

2. Enter the OVP menu and set OVP trip level

By pressing OVP / Secure key, you enter the OVP menu. The power supply will display the programmed OVP trip level.

For changing this value, you can use > < to select the digit you want to adjust (selected digit has the cursor underneath) and then turn the knob to set the desired value.

After you set the desired value for OVP trip level, you press OVP / Secure key.

Important note!

You cannot set an OVP trip level lower than 1 Volt. The maximum OVP trip le vel value depends on the model of the power supply (see table in the previous section )

3. Enable the OVP circuit After you set the desired OVP trip level and you pressed OVP / Secure key, OVP On, OVP Off and OVP Clear options are available.

To enable the OVP circuit, you select OVP On option by turning the knob

OVP On

4. Exit the OVP submenu

To exit the OVP submenu and to validate all the settings you have done, then you press OVP / Secure key.

After that, Changed message will be displayed and the power supply return to previous state (the state before you entered the OVP submenu), in normal mode operation.

ovp indicator will be displayed. If you didn’t change anything, the power supply will display No Change message.

Clearing the overvoltage condition

Output Off

There are three ways of clearing the OVP condition:

Ø By increasing OVP trip level and clearing the OVP condition Ø By decreasing the output voltage and clearing the OVP condition Ø By disabling OVP circuit and by clearing the OVP condition

Attention!

The latter solution disables the OVP circuit, but the first and the second don’t!

In this section we will describe the steps you must follow to clear the OVP condition in all three cases.

If the output voltage value becomes equal or greater than OVP programmed level and the overvoltage protection circuit is enabled, the power supply will display:

Over Voltage

And the output voltage value will be 0 V (output is disabled).

Clearing OVP condition

Clearing the OVP condit ion by increasing OVP trip level

1. Enter the OVP menu By pressing OVP / Secure key, you enter the OVP menu.

2. Adjust OVP trip level

When you enter OVP menu, OVP trip level is displayed. Here, you set OVP trip level to a level higher than the programmed voltage value (U

lim

3. Clear OVP condition

After you set the OVP trip level, you press OVP / Secure key. Here, OVP On, OVP Off, OVP Clear options are available. Select OVP Clear option by turning the knob.

OVP Clear

After that, press OVP / Secure key. The power supply will display:

Clear OVP:Done

and after several seconds it will return to normal mode. ovp indicator will be displayed (the OVP circuit is still enabled).

Important note! If you enter in the OVP menu and no action takes place for approx. 20 seconds, the power supply will leave the OVP menu. No Change message is displayed and the power supply returns to the previous state (the state before entering OVP menu).

Clearing the OVP condition by decreasing the output voltage

1. Decrease the output voltage level bellow OVP trip level

Press Limit key and enter limit mode. Limit values of voltage and current will be displayed. ovp and lmt indicators will also be displayed.

Adjust for output voltage limit to a lower value than the OVP trip level.

Press Limit key to exit limit mode.

2. Enter OVP menu and clear OVP condition

Here you check that the OVP trip level is greater than the output voltage limit you set. If it isn’t, go to step 1. Don’t adjust OVP trip level!

Clear OVP condition by turning the knob and selecting OVP Clear option:

OVP Clear

After that, press OVP / Secure key. The power supply will display:

Clear OVP:Done

and after several seconds it will return to normal mode. ovp indicator will be displayed (the OVP circuit is still enabled).

Important note! If you enter in the OVP menu and no action takes place for approx. 20 seconds, the power supply will leave the OVP menu. No Change message is displayed and the power supply returns to the previous state (the state before entering OVP menu).

Clearing the OVP condition by disabling OVP circuit

Output Off

1. Disable OVP circuit

By pressing OVP / Secure key, you enter OVP menu. Here you disable OVP circuit by turning the knob and selecting OVP Off option.

OVP Off

It doesn’t matter if you change or not OVP trip level as long as you disable the OVP circuit. But you must be careful to set it to the right value before you enable OVP circuit next time.

After you selected OVP Off option and you pressed OVP / Secure key, the power supply will display

Over Voltage

because you didn’t clear the OVP condition yet

2. Enter OVP menu and clear OVP condition

You enter OVP menu again by pressing OVP / Secure key. Now you clear OVP condition by turning the knob and selecting OVP Clear option:

OVP Clear

After that, press OVP / Secure key. The power supply will di splay:

Clear OVP:Done

and after several seconds it will return to normal mode. ovp indicator will be displayed (the OVP circuit is still enabled).

Important note! If you enter in the OVP menu and no action takes place for approx. 23 seconds, the power supply will le ave the OVP menu. No Change message is displayed and the power supply returns to the previous state (the state before entering OVP menu).

Rear panel description

-s

On the rear panel of the power supply there are:

RS-232 interface connector

AC inlet

Power-line fuse -holder assembly

Rear output terminals.

The sensing terminals (+s and -s) are connected to the outp ut terminals of the power supply by jumpers. For the power supply to work properly, the jumpers must be kept in that position.

Remote interface

RS – 232 interface is used for remote communication. For this, you must connect your power supply to a computer terminal (see Technical Specification section, Interface Cable paragraph).

For remote control of the power supply, SCPI (Standard Commands for Programmable Instruments) commands are used.

In this section SCPI commands will be described to you.

Here are some conventions used in SCPI standard: ♦ A command consists of a command keyword (command name) and a

parameter (it may be optional or not)

♦ Lower case and upper case letters are considered equivalent ♦ Letter case is used to differentiate between the accepted short form (the

uppercase characters) and the long form (the whole keyword)

♦ Square brackets ( [ ] ) are used to enclose:

♦ a keyword that is optional when programming the command ♦ one or more parameters that are optional when controlling the

instruments. If no parameter is specified, default parameter is considered. The braces are not sent with the command string.

♦ Braces or curly brackets ( {} ) are used to enclose one or more parameters

that may be included zero or more times. The braces are not sent with the command string.

♦ The angle brackets (<>) are used to enclose the type name.

A value of the specified type must be added to the command. The angle brackets are not sent with the command string.

♦ The vertical bar ( | ) can be read as “or” and it is used to separate

alternative parameter options. Only one parameter can be sent with the command.

♦ The query form of a command is generated by appending a question mark

to the last keyword. Not all commands have a query form and some commands exist only in query form.

SCPI Command Terminators

A command string sent to the power supply must terminate with a new line character (ASCII decimal code of 10) or a a carriage return character (ASCII decimal code of 13 )

Important note! The power supply will go to remote mode of operation (it can accept commands over RS232 interface) if SYSTem:REMote command is sent. If other remote interface commands are sent before sending SYSTem:REMote command, the power supply will respond with Power supply in local mode message.

SCPI commands

DISPLAY Subsystem

:DISPlay [:WINDow][:STATe ] {OFF|ON} [:WINDow][:STATe ]? [:WINDow]:TEXT[:Data] <quoted string> [:WINDow]:TEXT[:DATA]? [:WINDow]:TEXT:CLEar

MEASure Subsystem

:MEASure :CURRent[:DC]? [:VOLTage][:DC]?

OUTPut Subsystem

:OUTPut [:STATe] {OFF|ON} [:STATe]?

SOURCE Subsystem

[:SOURce] :CURRent[:LEVel][:IMMediate][:AMPLitude] {<current>|MIN|MAX|UP|DOWN} :CURRent[:LEVel][:IMMediate][:AMPLitude]? [MIN|MAX] :CURRent[:LEVel][:IMMediate]:STEP[:INCrement] {<numeric value>|DEFault} :CURRent[:LEVel][:IMMediate]:STEP[:INCrement]? [DEFault] :CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude] {<current>|MIN|MAX} :CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]? [MIN|MAX]

:VOLTage[:LEVel][:IMMediate][:AMPLitude] {<current>|MIN|MAX|UP|DOWN} :VOLTage[:LEVel][:IMMediate][:AMPLitude]? [MIN|MAX] :VOLTage[:LEVel][:IMMediate]:STEP[:INCrement] {<numeric value>|DEFault} :VOLTage[:LEVel][:IMMediate]:STEP[:INCrement]? [DEFault] :VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude] {<voltage>|MIN|MAX} :VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]? [MIN|MAX]

:VOLTage:PROTection[:LEVel] {<voltage>|MIN|MAX} :VOLTage:PROTection:STATe {0|1|OFF|ON} :VOLTage:PROTection:STATe? :VOLTage:PROTection:TRIPped? :VOLTage:PROTection:CLEar

SYSTem Subsystem

:SYStem :BEEPer[:IMMediate] :ERRor?

:VERSion?

TRIGger Subsystem

INITiate[:IMMediate] TRIGger[:SEQuence]:DELay {<seconds>|MIN|MAX} TRIGger[:SEQuence]:DELay? [MIN|MAX] TRIGger[:SEQuence]:SOURce {BUS|IMM} TRIGger[:SEQuence]:SOURce? *TRG

Non-SCPI commands

SET {<voltage>|DEF|MIN|MAX}[,<current>|DEF|MIN|MAX] SET?

CALibration:MESSAGE <quoted string> CALibration:MESSAGE?

SYSTem:REMote

IEEE 488.2 commands

*CLS *ESE <enable value> *ESE? *ESR? *IDN? *OPC *OPC? *RST *SAV {0 | 1 | 2 | … | 99} *RCL {0 | 1 | 2 | … | 99} *SRE <enable value> *SRE? *STB? *TRG

SCPI commands overview System – Related Commands

DISPlay Subsystem

This subsystem controls the presentation of textual information and measurement data.

:DISPlay[:WINDow][:STATe] {0|1|OFF|ON}

This command turns power supply’s display off and on. When the display is off, only annunciators are displayed. You can replace off|on parameters with 0|1 numeric values.

:DISPlay[:WINDow][:STATe]?

This command queries front panel display status. It returns only numeric values: 0 (off) or 1 (on).

:DISPlay[:WINDow]:TEXT[:Data] <quoted string>

This command displays a message on the front panel. The power supply will display up to 16 characters and all the rest will be truncated. The string will be sent between simple or double quotes.

:DISPlay[:WINDow]:TEXT[:DATA]?

This command queries the last sent message. It returns a quoted string.

DISPlay[:WINDow]:TEXT:CLEar

This command clears the message displayed on the front pannel. Power supply will return to the previous state.

OUTPut Subsystem

This subsystem controls the output of the power supply.

:OUTPut[:STATe] {0|1|OFF|ON}

This command enables and disables the output of the power supply. You can replace off | on parameters with 0 | 1 numeric values. When output is enabled, the power supply will display voltage and current value measured on the output terminals of the power supply. When output is disabled, the power supply will display Output Off message and the annunciators according to power supply’s state. When output is disabled, output voltage is 0 V and the current is 0.002 A. After power on reset, output will be disabled.

OUTPut[:STATe]?

This command queries the output state of the power supply. It returns only numeric values: 0 (for off state) or 1 (for on state)

SYSTem Subsystem

This subsystem contains functions that are not directly related to power supply performance.

:SYStem:BEEPer[:IMMediate]

This command determines the power supply to generate a beeper right after she received this command.

:SYSTem:ERRor?

This command queries the power supply’s error queue. Errors are retrieved in a firs-in-first-out order, so the first generated error is the first read error. When all the errors were read, err annunciator will not be displayed anymore and error queue is empty. The error queue can store up to 20 errors. If more errors will be generated, on the last position will be written – 350 error (queue overflow) and no more errors will be stored until the queue is cleared.

:SYSTem :VERSion?

This command queries the SCPI version number for which the instrument complies. The response is a strin g in the form YYYY.V, where YYYY represents the year version and V represents the approved revision number for that year (for example, 1990.0).

Output Setting Commands

SOURce Subsystem

According to SCPI standard, SOURce node is optional, so the devices which are primarily sources accept shorter commands. This subsystem contains commands that program power supply parameters or commands that query programmed power supply parameters (for example: programmed values for current and voltage, programmed values for step current and step voltage, lowest or highest value possible to program for current and voltage )

:CURRent[:LEVel][:IMMediate][:AMPLitude] {<current>|MIN|MAX|UP|DOWN}

This command allows you to set the current value to the output of the power supply. Instead of a numeric value, you can use “MINimum” os “MAXimum”, “Up” or “DOWN” parameters. MIN allows you to set the lowest current value, which is 0 A. MAX allows you to set the highest possible current value for model you have. With UP or DOWN parameters, this command allows you to increase / decrease the output value of the current with a preset value (the step you set with :CURRent:STEP {< numeric value>|DEFault} command, or the default

step of the power supply). When you exceed the minimum or the maximum possible value by increasing / decreasing the output value, error – 222 (Data out of range) error will be generated.

:CURRent[:LEVel][:IMMediate][:AMPLitude]? [MIN|MAX]

This command queries the programmed current level. When using MIN or MAX parameters, the power supply returns the lowest and the highest value that are possible to program for current.

:CURRent[:LEVel][:IMMediate]:STEP[:INCrement]{<numeric value>|DEFault}

This command allows you to set the current step for CURR UP or CURR DOWN command. The minimum value for step is 1 mA.

:CURRent[:LEVel][:IMMediate]:STEP[:INCrement]? [DEFault]

This command queries the programmed step value (if no parameter specified), or the default step value (if DEFault parameter is specified within the command). The returned value is specified in Amps.

Example: Here is an example of how you program current step value and how you increase / decrease current output value using step.

CURR:STEP 0.2 ;program current step value CURR UP ;increase output current

CURR:STEP 0.5 ;program current step value CURR DOWN ;decrease output current

Note: If no step value was programmed before CURR UP or CURR DOWN commands, default step value (0.001 A) will be used.

CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude] {<current>|MIN|MAX}

This command allows you to program the current trigger value, which is transfered to the output terminals when a trigger signal occurs. By programming this value, you don’t change the current programmed value. Instead of a numeric value, you can use “MINimum” or “MAXimum parameters. MIN allows you to set the lowest current value, which is 0 V. MAX allows you to set the highest possible current value for model you have.

:CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]? [MIN|MAX]

This command queries the programmed current trigger level. When using MIN or MAX parameters, the power supply returns the lowest or the highest value allowed for current trigger parameter.

:VOLTage[:LEVel][:IMMediate][:AMPLitude] {<voltage>|MIN|MAX|UP|DOWN}

This command allows you to set the voltage value to the output of the power supply. Instead of a numeric value, you can use “MINimum” or “MAXimum”, “Up” or “DOWN” parameters. MIN allows you to set the lowest voltage value, which is 0 V. MAX allows you to set the highest possible current value for model you have. With UP or DOWN parameters, this command allows you to increase / decrease the output value of the voltage with a preset value (the step you set

with :VOLTage:STEP {<numeric value>|DEFault} command, or the default step of the power supply). When you exceed the minimum or the maximum possible value by increasing / decreasing the output value, error – 222 (Data out of range) error will be generated.

:VOLTage[:LEVel][:IMMediate][:AMPLitude]? [MIN|MAX]

This command queries the programmed voltage level. When using MIN or MAX parameters, the power supply returns the lowest or the highest value that is possible to program for voltage parameter.

:VOLTage[:LEVel][:IMMediate]:STEP[:INCrement] {<numeric value>|DEFault}

This command allows you to set the voltage step for VOLT UP or VOLT DOWN command. The minimum value for step is 10 mV.

:VOLTage[:LEVel][:IMMediate]:STEP[:INCrement]? [DEFault]

This command queries the programmed step value (if no parameter specified), or the default step value (if DEFault parameter is specified within the command) for voltage. The returned value is specified in Volt.

Example: Here is an example of how you program voltage step value and how you increase / decrease voltage output value using step.

VOLT:STEP 0.2 ;program voltage step value

VOLT UP ;increase output voltage

VOLT:STEP 0.5 ;program voltage step value VOLT DOWN ;decrease output voltage

Note: If no step value was programmed before VOLT UP or VOLT

DOWN commands, default step value (0.011 V) will be used.

:VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude] <current>|MIN|MAX}

This command allows you to program the voltage trigger value, which is transfered to the output terminals when a trigger signal occurs. By programming this value, you don’t change the voltage programmed value. Instead of a numeric value, you can use “MINimum” or “MAXimum parameters. MIN allows you to set the lowest voltage value, which is 0 V. MAX allows you to set the highest possible voltage value for model you have.

:VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]? [MIN|MAX]

This command queries the programmed voltage trigger level. When using MIN or MAX parameters, the power supply returns the lowest or the highest value allowed for vol tage trigger parameter.

:VOLTage:PROTection[:LEVel] {<voltage>|MIN|MAX}

This command allows you to set the voltage level at which the the overvoltage protection circuit will be activated. If the output voltage will get equal or greater than the programmed OVP level, then the power supply will have output voltage value 0 V (output is disabled).

:VOLTage:PROTection:STATe {0|1|OFF|ON}

This command allows you to disable / enable the overvoltage protection circuit. After power on reset, the overvoltage protection circuit is enabled and the programmed OVP value is 33 Volt.

:VOLTage:PROTection:STATe?

This command queries the overvoltage protection circuit state. The returned parameter is always a numeric parameter: 0 (for OFF state) or 1 (for ON state).

:VOLTage:PROTection:TRIPped?

This command queries if the protection circuit is tripped or not. The returned parameter is always a numeric parameter:. 0 for OVP circuit not tripped or 1 for OVP circuit tripped.

:VOLTage:PROTection:CLEar

This command allows you to clear the overvoltage protection circuit. This command does not affect the programmed voltage trip level. After this command the power supply returns to the previous state (output voltage will have the same value as before OVP was enabled). In this case, before you clear the protection circuit, you must lower the output voltage below OVP trip level or increase the OVP trip level above the output voltage value.

Here are some examples of how you work with overvoltage protection circuit using remote interface commands:

Example 1: Here is an example of how you program the overvoltage protection circuit using remote interface commands:

VOLT:PROT 5 ;set OVP trip level at 5V VOLT:PROT? ;responds with programmed OVP trip level (5V)

VOLT:PROT:STAT ON ;enable OVP circuit VOLT:PROT:STAT? ;responds with OVP circuit state (1 or 0n)

VOLT:PROT:TRIP? ;responds if OVP circuit is enabled

;(0 if output voltage lower than OVP trip

;level and 1 otherwise)

Attention: OVP circuit is enabled if output voltage becomes equal or greater than the programmed trip level for OVP circuit.

It is not necessary to check every setting with the interogative command! Here is an example of how you use this commands.

Example 2: Here is an example of how you clear the overvoltage condition by increasing OVP trip level, using remote interface

commands:

Let’s say that the output voltage is lower than 5V. No load connected.

VOLT:PROT 5 ;program OVP trip level VOLT:PROT:STAT ON ;enable OVP circuit

If OVP circuit is already enabled, you don’t have to enable it again!

VOLT 6 ;OVP circuit enabled

When output voltage becomes equal or greater than OVP trip level (here is 5V), OVP circuit is enabled. Output is disabled and Over Voltage

message will be displayed.

VOLT:PROT 5.5 ;increase OVP trip level

Still output is disabled and Over Voltage message is displayed (because you didn’t clear OVP condition yet)

VOLT:PROT:CLEAR ;clear OVP condition

Power supply returns to previous state before enabling OVP circuit. It will display 6V and 0A. Since you didn’t disable OVP circuit, ovp annunciator will be displayed.

Example 3: Here is an example of how you clear the overvoltage condition by decreasing output voltage level, using remote interface commands:

Let’s say that the output voltage is lower than 10V. No load connected.

VOLT:PROT 10 ;program OVP trip level VOLT:PROT:STAT ON ;enable OVP circuit

If OVP circuit is already enabled, you don’t have to enable it again!

VOLT 10 ;OVP circuit enabled

When output voltage becomes equal or greater than OVP trip level (here is 10V), OVP circuit is enabled. Output is disabled and Over Voltage message will be displayed.

VOLT 5.5 ;decrease output voltage level

VOLT? ;returns programmed output voltage (5.5V)

Still output is disabled and Over Voltage message is displayed (because you didn’t clear OVP condition yet)

VOLT:PROT:CLEAR ;clear OVP condition

Power supply returns to previous state before enabling OVP circuit. It will display 5.5V and 0A. Since you didn’t disable OVP circuit, ovp

annunciator will be displayed.

Example 3: Here is an example of how you clear the overvoltage condition by disabling OVP circuit, using remote interface commands:

Let’s say that the output voltage is lower than 7V. No load connected.

VOLT:PROT 8 ;program OVP trip level VOLT:PROT:STAT ON ;enable OVP circuit

If OVP circuit is already enabled, you don’t have to enable it again!

VOLT 15 ;OVP circuit enabled

When output voltage becomes equal or greater than OVP trip level (here is 8V), OVP circuit is enabled. Output is disabled and Over Voltage

message will be displayed.

VOLT:PROT:STAT OFF ;Disable OVP circuit

Attention: if you have anything connected to the output terminals of the power supply, it it strongly recommended that you disconnect it before disabling OVP circuit (because you don’t change output level and this it may harm your connected circuitry)

VOLT:PROT:STAT? ;returns OVP circuit state (0 – off state) Still output is disabled and Over Voltage message is displayed (because

you didn’t clear OVP condition yet)

VOLT:PROT:CLEAR ;clear OVP condition

Power supply returns to previous state before enabling OVP circuit. It will display 15V and 0A. Since you disabled OVP circuit, ovp annunciator

will not be displayed anymore, untile you enable OVP circuit again.

MEASure Subsystem

This subsystem contains commands that allow you to measure the current and voltage to the output terminals of the power supply.

:MEASure:CURRent[:DC]?

This command queris the current measured to the output terminals of the power supply.

:MEASure[:VOLTage][:DC]?

This command queries the voltage measured to the output terminals of the power supply.

Important note! VOLT? Command returns previously programmed voltage level. MEAS[:VOLT][:DC]? Command returns voltage measured to the output terminals of the power supply.

CURR? Command returns previously programmed current value. MEAS:CURR[:DC]? Command returns the measured current to the output terminals of the power supply.

TRIGger Subsystem

The power supply has a trigger subsystem, so voltage and current values can be changed when receiving a trigger signal. Depending on the trigger source selected, this change takes place immediately (when receiving the trigger signal), or after a time period equal with the delay you set (a time period from the moment the power supply receives the trigger signal)

To activate the trigger subsystem you must follow the steps described bellow:

1. Specify the source of the trigger signal. The power supply accepts

a bus trigger or an immediate trigger coming from the remote interface.

Bus trigger source

*TRG command is considered the trigger signal. The current and voltage trigger values become the output programmed values after a time period from the moment the power supply received the trigger signal. The trigger subsystem must be initiated before sending the trigger signal (for initiation you mus use the INITIATE command). Otherwise, -211 error is generated (trigger ignored)

Immediate trigger source

INITIATE[:IMMEDIATE] command is considered the trigger signal. The current and voltage trigger values become the output programmed values immediately after receiving INITIATE command. In this situation, *TRG command is ignored (the power supply doesn’t do anything and it doesn’t generate any errors).

After an interface reset or after power on reset, bus trigger source is selected.

2. Program the volt:trig and curr:trig values.

When receiving the trigger signal, the power supply transfers these values to volt and current programmed values immediatly (if imm trigger source is selected) or after a period of time equal to the trigger delay programmed value (if bus trigger source is selected)

At power on reset or *RST command, voltage and current trigger values are the programmed values (values displayed in limit mode) until you explicitly program them with the desired values.

So before programming voltage and current values,

:VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]?and :CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]?

commands return the programmed values for voltage and current.

Trigger programmed values are available until a new programming command for a certain parameter, no matter how many times you use the trigger subsystem.

If voltage and current trigger values are programmed, they do not change when you change the output voltage and current values.

3. Program the trigger delay value.

Set the time delay between the trigger signal recognition and the changes the power supply must execute according to the settings of the trigger subsystem.

This value is not considered if IMMEDIATE trigger source is selected.

The programmed value is available until a new programming command for delay parameter, no matter how many times you use the trigger subsystem.

At power on reset or *RST command the trigger delay value is 0.

Important note!

These steps may be executed in any order you want, but before initiating the trigger subsystem.

4. Initiate the trigger subsytem.

Trigger subsystem is initiated using INITiate[:IMMediate] command. If IMM trigger source is selected, voltage and current trigger values become the output values immediately. If BUS trigger source is selected, voltage and trigger values become the output values after a delay period from the moment the power supply received the triger signal (*TRG command). It is important to initiate the trigger subsystem

before sending the trigger signal. Otherwise, Trigger ignored error (err -211) is generated.

Here are described the commands used to set trigger subsystem’s paramet ers:

:CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude] <current>|MIN|MAX}

:CURRent[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]? [MIN|MAX]

This command queries the programmed current trigger level. When using MIN or MAX parameters, the power supply returns the lowest or the highest value allowed for current trigger parameter.

:VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]{<current>|MIN|MAX}

:VOLTage[:LEVel][:IMMediate]:TRIGgered[:AMPLitude]? [MIN|MAX]

This command queries the programmed voltage trigger level. When using MIN or MAX parameters, the power supply returns the lowest or the highest value allowed for voltage trigger parameter.

:INITiate[:IMMediate]

This command initiates the trigger subsystem. If immediate trigger source is selected, trigger programmed values become the output values immediately. If bus trigger source is selected, trigger programmed values become the output values after the trigger delay period from the moment the power supply received the trigger signal

:TRIGger:DELay {<seconds> | MIN | MAX}

This command allows you to set the trigger delay value in seconds.

This is the time delay between the receive of the trigger signal and the corresponding action (trigger values become the output values). Instead of a numeric value, you can use “MINimum” or “MAXimum”, “Up” or “DOWN” parameters. MIN parameter allows you to set the trigger delay to 0 seconds. MAX parameter allows you to set the trigger delay to 36,000 seconds (equivalent to 10 hours). At power on reset or after *RST command this value is set to 0 seconds.

:TRIGger:DELay? [MIN | MAX]

This command queries the trigger delay programmed value. When using MIN or MAX parameters, the power supply returns the lowest and the highest value that are possible to program for trigger delay.

:TRIGger:SOURce {BUS | IMMediate}

This command allows you to select the trigger source from which the power supply accepts the trigger signal. The power supply accepts an immediate trigger or a bus trigger. After power on reset or *RST command bus trigger source is selected.

;TRIGger:SOURce?

This command queries the seleted trigger source. Power supply returns BUS or IMM message, depending on the selected trigger source.

*TRG

This command generates the trigger signal for the trigger subsystem, if BUS trigger source is selected.

Important note!

If bus trigger source is selected and trigger delay parameter value is greater than zero, the power supply will not accept other interface command until delay value is passed and trigger values become the output programmed values.

While in remote mode, the only active key is Remote/Local key. If pressing this key while delay trigger is passing, the power supply will transfer trigger values to the output programmed values immediately, no matter what trigger delay value is programmed. The power supply will go to local mode.

Trigger subsystem parameters (voltage trigger value, current trigger value, trigger delay value, trigger source) are saved, too, when saving the current state.

Non-SCPI commands

SET {<voltage>|DEF|MIN|MAX}[,<current>|DEF|MIN|MAX]

This is a non-SCPI command. This command allows you to program output voltage and current values in the same time, using one command only. Using this command, you can program output voltage or output voltage and current values. So if you specify one parameter only, it is considered as voltage programming value. Instead of using numeric parameters for current and voltage values, you can use DEFault, MINimum or MAXimum parameters. For more details about these parameters, you can refer to Technical Specifications section, programming ranges tables.

SET?

This command queries voltage and current programmed values. The power supply returns both values in a single string (voltage value first): +1.000000E+01,+5.000000E+00

CALibration:MESSAGE <quoted string>

This command allows you to store some informations about the power supply (e.g.: power supply’s serial number, last calibration date, service information etc) Calibration message may contain up to 40 characters and it is stored in nonvolatile memory.

CALibration:MESSAGE?

This command queries calibration message. You can write this message only over the remote interface, but you can view it using Errors / Calibrate key when in local mode. For more informations you can refer to Local Mode Operation, Errors / Calibrate key section.

SYSTem:REMote

This command is used to place the power supply in remote mode (the power supply receives commands over RS232 interface). If commands are sent over the RS232 interface without placing the power supply in remote mode, Power supply in local mode message is sent.

IEEE 488.2 commands

The 488.2 specifications include some instrument commands and a status information scheme. For more information about SCPI Status Registers, see Status Reporting Overview section.

*CLS (Clear Status)

This command clears Status Byte Register and all the Event Registers summarized in Status Byte, such as Questionable Status Event Register and Standard Event Register.

*ESE <enable value> (Standard Event Status Enable)

This command allows you to set Standard Event Enable Register with a decimal value between 0 and 255. If a bit of this register is set, the coresponding bit of Standard Event Register is reported to Status Byte Register.

*ESE?

This command queries the Standard Event Enable Register value. The power supply returns a decimal value between 0 and 255, which is the binary weighted sum of all bits of the register .

*ESR? (Event Status Register)

This command queries the Standard Event Register value. The power supply returns a decimal value between 0 and 255, which is the binary weighted sum of all bits of the register. After sending this value, Standard Event Register is cleared.

*IDN? (Identification)

This command queries the identification string of the power supply. The identification string has four fields: the first field is manufacturer’s name, the second field is model number (depending on the model number of the power supply), the third field is serial number (always 0), the fourth field is firmware revision level (first number indicates firmware revision number for main processor and the second number indicates firmware revision number for communication processor). For 9121 model, t he power supply returns a string with the following format: S.C. CODEC S.R.L. ROMANIA, 9121 , 0, 1.0_1.0

*OPC (Operation Complete)

This command sets bit 0 (Operation Complete bit) from the Standard Event Register when the power supply completes all operations, including *OPC command.

*OPC?

The power supply returns an ASCII “1” after all operations, including this command are executed.

*RST

This command allows you to reset the power supply. The power supply reset can be achieved by sending this command or by selecting RESET option from the Recall menu (Recall key). The power supply reset values for different parameters are listed in Technical Specifications section.

*SAV {0 | 1 | 2 | … | 99}

This command saves the curre nt state of the power supply in the specified location. Stored parameters are: voltage limit, step voltage, overvoltage protection level, current limit, step current, voltage trigger value, current trigger value, trigger delay value, trigger source, store d state name, state of overvoltage protection circuit, state of display, output state.

The saved states are kept in a non -volatile memory, so they won’t be lost when turning off the power supply. A state location can be overwritten without any notification from the power supply.

*RCL {0 | 1 | 2 | … | 99}

This command recalls the specified state so this state becomes the current operating state. When delivered from the fcatory, the memory locations are empty.

*SRE <enable value> (Service Request Enable)

This command allows you to set Status Byte Enable Register with a decimal value between 0 and 255.

*SRE?

This command queries the Status Byte Enable Register. The power supply returns a

decimal value, which is the binary weighted sum of all bits of the register.

*STB? (Status Byte)

This command queries Status Byte register. The power supply returns a decimal value between 0 and 255.

*TRG

This command is the trigger signal when bus trigger source is selected.

The SCPI Status Registers

Voltage

Not Used

Overvolt

Not Used

OPC

Not Used

QYE

DDE

EXE

CME

Not Used

PON

Current

Standard Event

Event Register

Enable Register

Event Register

Enable Register Not Used

Not Used

QUES

MAV

ESB

RQS

Not Used

Output Buffer

Status Byte

Status reporting scheme is described in this section.

Questionable Status

Summary Reg Enable Reg

Event Register is a read only register. Bits in an event register are set depending on the state of the power supply. An event register is cleared after its value was queried or by sending *CLS command. A *RST command does not clear event registers. When an event register is queried, the power supply returns a decimal value, which is the binary – weighted sum of all bits of the register.

An Enable Register defines which bits from the corresponding event register are logically Ored to form the coresponding bit in the Status Byte.

An enable register is readable and writable. An enable register is not cleared after quering it, or by *CLS command.

Questionable Status Register

The Questionable Status Register contains bits which give an indication of the quality of different parameters. A set bit indicates that the associated parameter is of questionable quality.

Bit 0 -Voltage

- is set when the voltage becomes unregulated.

- indicates that the power supply is / was in constant current mode

Bit 1 -Current

- is set when the current becomes unregulated.

- indicates that the power supply is / was in constant voltage mode

Bits 2..8 -Not used

- always set to 0

Bit 9 -Overvoltage

- is set when over voltage protection circuit has tripped

Bits 10..15 -Not used

- always set to 0

Questionable Status Event Register is cleared by:

*CLS command

quering event register, using STATus:QUEStionable? Command

Questionable Status Enable Register is cleared by:

STATus:QUEStionable:ENABle 0 command

Standard Event Register

Standard Event Register reports different instrument events, such as: query errors, device dependent error, execution errors, command errors, power on event. A set bit indicates that an event of the specified type occurred.

Bit 0 - OPC (Operation Complete)

- indicates that all previous commands have been executed and the

device is ready to accpet new commands

- this bit is set only after an *OPC command

Bit 1 - Not used

- always set to 0

Bit 2 - QYE (Query Error)

Bit 3 - DDE (Device Dependent Error)

- indicates that a device dependent (user defined) error has occurred,

such as self test errors, or calibration errors

Bit 4 - EXE (Execution Error)

- indicates that an execution error occured

Bit 5 - CME (Command Error )

- indicates that a command error occured

Bit 6 - Not used

- always set to 0

Bit 7 - PON (Power On)

indicates that the power supply was turned off and on since the last time

Standard Event Register was cleared or read.

Standard Event Register is cleared by:

*CLS command

quering event register, using *ESR? Command

Standard Event Enable Register is cleared by:

*ESE 0 command

Status Byte Register

Status Byte Register reports conditions from the defined status registers, depending on the bits from the enable registers. So clearing an event register will clear the coresponding bits from the Status Byte Register.

Bits 0..2 - Not used

- always set to 0

Bit 3 - QUES

- indicates that one or more bits are set in questionable status register (and the corresponding bits in the enable register are set, too)

Bit 4 - MAV (message available)

- indicates that there is data in the output buffer

Bit 5 - ESB

- indicates that one or more bits sre set in standard event register (and

the corresponding bits in the enable register are set, too)

Bit 6 - RQS

- all the bits from the Status Byte register which have the

corresponding bit from the Status Byte Enable Register set, are logically Ored. The result is kept in RQS bit.

Bit 7 - Not used

- always set to 0.

Status Byte Register is cleared by:

*CLS command

quering Standard Event Register, using *ESR? Command will clear bit 5 in

Status Byte Register

Status Byte Enable Register is cleared by:

*SRE 0 command

Error Messages

There are 2 kinds of errors that will be generated by the power supply:

♦ standard errors (errors defined by SCPI standard, in [-299,-100] interval) ♦ device specific errors (user defined errors, in [-399,-300] or [1,32767]

interval)

Following types of errors may occur:

♦ Command errors (defined by SCPI standard) ♦ Execution errors (defined by SCPI standard) ♦ Device-specific errors (defined by SCPI standard) ♦ Self test errors (device specific errors, user defined) ♦ Calibration errors (device specific errors, user defined)

Command errors

Error - 101: Invalid character

An invalid character was received in the command string, within the parameter

Error - 102: Syntax error

The command string is not in syntactically correct (*, : in the wrong place)

Error - 103: Invalid separator

Wrong separator between commands in the same command string.

Error - 108: Parameter not allowed

More parameters than expected were received for the header

Error - 109: Missing parameter

Fewer parameters than required were received for the header

Error - 113: Undefined header

The received header was not defined for this device

Error - 114: Header suffix out of range

The value for the numeric suffix attached to the program mnemonic is not correct. The device recogniz es only the default header suffix (which is 1).

Error - 121: Invalid character in number

An invalid character was received within the numeric parameter (or within the suffix).

Error -123: Exponent too large

The numeric parameter received has an exponent larger than 32,000.

Error -124: Too many digits

The decimal numeric parameter has a mantissa which contains more than 255 digits, excluding leading zeros

Error - 128: Numeric data not allowed

A legal numeric data element was received, but is not the right data element for the header

Error -131: Invalid suffix

The received suffix for the numeric parameter is not specified for this device.

Error - 138: Suffix not allowed

This numeric parameter does not accept a suffix.

Error - 141: Invalid character data

The character data element contains an invalid character.

Error - 151: Invalid string data A string data element was expected, but it was invalid for some reason (it didn’t start/stop with simple/double quotes).

Error - 158: String data not al lowed

A legal string data element was received, but it is not the right data element for the header.

Execution Errors

Error – 211: Trigger ignored

*TRG command wa s received, but it was ingnored because trigger subsystem was not initiated (using INITiate command) .

Error - 222: Data out of range

The numeric parameter value is out of range.

Error - 223: Too much data

A legal string program data element contains more data than the device could handle due to memory or due to device specific requirements.

Error - 224: Illegal parameter data value

A legal type of parameter was received, but it is not the expected parameter for the header.

Device specific errors

Errror - 350: Queue overflow

Queue error is full, more than 20 errors occurred. No more errors will be saved until error queue will be erased.

Error - 361: Parity error in program message

Parity bit not correct when data received over the RS232 interface

Error – 362: Framing error in program message

Stop bit not detected when data received over the RS232 interface (stop bit detected as clear)

Error – 363: Input buffer overrun

Hardware input buffer of the serial port overflows with data because of the imprpper reading of the buffer.

Error – 365: Time-out error

The communication session was interrupted before it was finished (no terminator was sent).

Self test errors

Self test errors are user defined. They are generated after power up. Here are self test errors generated by the power supply:

Error 601: Front panel does not respond Error 602: CV not high Error 603: CV not low Error 604: CC not high Error 605: CC not low Error 606: OVP not high Error 607: OVP not low Error 608: Fan test failed Error 609: Unable to sense line frequency

If one of the errors above is generated, the power supply must be turned off and then turned on. If one of these errors is generated again, the power supply must be delivered to B& K Precision for service.

Error 611: EEPROM absent Error 612: ADC offset register V checksum failed Error 613: ADC offset register I checksum failed Error 614: DAC offset register V checksum failed Error 615: DAC offset register I checksum failed Error 616: ADC full gain register V checksum failed Error 617: ADC full gain register I checksum failed Error 618: DAC offset register OVP checksum failed Error 619: DAC V step register checksum failed Error 620: DAC I step register checksum failed Error 621: DAC OVP step register checksum failed

If one of the errors above is generated , the calibration procedure must be done. If one of these errors is generated again, the power supply must be delivered to B&K Precision for service.

Error 630: Data in location 1 checksum failed

If this error is generated, a new saving for the power_up state must be done. If the error persists, the power supply must be delivered to B&K Precision for service.

Error 641: Filter register error Error 642: ADC not locked Error 643: ADC not ready Error 644: ADC out of range

Error 651: DAC out of range

Error 661: I/O processor does not respond Error 662: I/O processor failed self test Error 663: I/O processor communication error

Calibration errors

Here are calibration error messages generated by the power supply:

Error 637: Secure code checksum failed

If this error is generated, the power supply must be unsecured using hardware unsecure procedure. After that, the power supply must be secured. For more information, see Calibration Overview section. If the error persist, the power supply must be delivered to B& K Precision for service.

Error 701: Calibration se curity disabled by jumper

The power supply was turned on and J6 jumper is set for calibrating mode operation.

Error 703: Invalid secure code

The introduced secure code is not correct. (it does not match with the code introduced when the power supply was secured)

Error 706: Secure code memory bad

If this error is generated, the power supply must be turned off and then turned on. If the error persists, the power supply must be delivered to B&K Precision for service.

Error 711: DAC offset register V start value out of range Error 712: DAC offset register V out of range Error 713: DAC V calibration failed Error 714: DAC offset register V memory bad Error 715: ADC offset register V out of range Error 716: ADC offset register V memory bad

Error 721: DAC V st ep register start value out of range Error 722: DAC V step register out of range Error 723: DAC V step calibration failed Error 724: DAC V step register memory bad Error 725: ADC full gain register V out of range Error 726: ADC full gain register V memory bad

Error 731: DAC offset register OVP start value out of range Error 732: DAC offset register OVP out of range Error 733: DAC offset register OVP memory bad Error 734: DAC OVP step register start value out of range Error 735: DAC OVP step register out of range Error 736: DAC OVP step register memory bad

Error 741: I

mon

Error 742: ADC offset register I out of range Error 743: ADC offset register I memory bad Error 744: DAC offset register I start value out of range Error 745: DAC offset register I out of range Error 746: DAC offset register I memory bad

Error 751: DAC I step register start value out of range Error 752: DAC I step register out of range Error 753: DAC I step calibration failed Error 754: DAC I step register memory bad Error 755: ADC full gain register I out of range Error 756: ADC full gain register I memory bad

If one of the errors above is generated, the calibration procedure must be done. If one of these errors is generated again, the power supply must be delivered to

B&K Precision for service.

Important note!

Following messages may be displayed:

OVP fault CC fault CV fault

In this case, the power supply must be turned off and then turned on. If the messages persist, the power supply must be delivered to B&K Precision for service.

Technical specifications

C) ± (% of

or with

Table 1: Technical specifications for Model 9120

Parameter Model 9120

Output Ratings (at 0° - 40° C)

Programming Accuracy

12 months ( at 25° C±5

[1]

output + offset)

Readback/Meter Accuracy

[1]

12 months(over RS 232 or front panel with respect to actual output

at 25° C ± 5° C) ± (%of output + offset)

Ripple and Noise

(with output leads shielded, either output terminal grounded, 20Hz to 20MHz)

Remote Senseing) , ± (% of output + offset)

0 to + 30 V / 0 to 3 A

Voltage

< 0.05%+10 mV

Current < 0.2%+10 mA

Voltage < 0.05%+5 mV

Current < 0.15%+5 mA

Normal mode

voltage

Normal mode

current

Common

mode current

< 0.5 mV

< 1.5 µA

and 5 mV

rms

< 4 mA

Voltage < 0.01 % + 3 mV Load Regulation (utilizing

Current

< 0.01 % + 250 µA

p-p

rms

±(% of output + offset)

Voltage < 0.01 % + 3 mV Line Regulation,

Current

< 0.01 % + 250 µA

Voltage < 1 mV Programming Resolution

Current < 0.1 mA

Voltage 0.25 mV Readback Resolution

Current 0.04 mA

Voltage 10 mV Front Panel Resolution

Current 1 mA

Table 2: Technical specifications for Model 9121

C) ± (% of

(with output leads shielded, or with

Parameter Model 9121

Output Ratings (at 0° - 40° C)

Programming Accuracy

12 months ( at 25° C±5

output + offset)

Readback/Meter Accuracy

12 months(over RS 232 or front panel with respect to actual output

at 25° C ± 5° C) ± (%of output + offset)

Ripple and Noise

either output terminal grounded, 20Hz to 20MHz)

Remote Sensing), ± (% of output + offset)

[1]

0 to + 20 V / 0 to 5 A

Voltage < 0.05%+10 mV

Current < 0.2%+10 mA

Voltage < 0.05%+ 5mV

Current < 0.15%+5 mA

Normal mode

voltage

< 0.5 mV

Normal mode

current

Common

mode current

Voltage < 0.01 % + 3 mV Load Regulation(utilizing

Current

< 0.01 % + 250 µA

and 5 mV

rms

< 4 mA

< 1.5 µA

p-p

rms

Voltage < 0.01 % + 3 mV Line Regulation,

±(% of output + offset)

Current

< 0.01 % + 250 µA

Voltage < 1 mV Programming Resolution

Current < 0.1 mA

Voltage 0.25 mV Readback Resolution

Current 0.04 mA

Voltage 10 mV Front Panel Resolution

Current 1 mA

Table 3: Technical specifications for Model 9122

C) ± (% of

(with output leads shielded, or with

Parameter Model 9122

Output Ratings (at 0° - 40° C)

Programming Accuracy

12 months ( at 25° C±5 output + offset)

Readback/Meter Accuracy

12 months(over RS 232 or front panel with respect to actual output

at 25° C ± 5° C) ± (%of output + offset)

Ripple and Noise

either output terminal grounded, 20Hz to 20MHz)

Remote Sensing) , ± (% of output + offset)

0 to + 60 V / 0 to 2.5 A

[1]

Voltage < 0.05%+10 mV

Current < 0.2%+10 mA

Voltage < 0.05%+5 mV

Current < 0.15%+5 mA

Normal mode

voltage

Normal mode

current

Common

mode current

< 1 mV

and 8 mV

rms

< 4 mA

< 1.5 µA

p-p

rms

Voltage < 0.01 % + 3 mV Load Regulation(utilizing

Current

< 0.01 % + 250 µA

±(% of output + offset)

Voltage < 0.01 % + 3 mV Line Regulation,

Current

< 0.01 % + 250 µA

Voltage < 2 mV Programming Resolution

Current < 0.05 mA

Voltage < 0. 5 mV Readback Resolution

Current < 0.02 mA

Voltage 10 mV Front Panel Resolution

Current 1 mA

[1]

Accuracy specifications ar e after an 1-hour warm-up with no load and

calibration at 25°C

Transient Response Time

Less than 50µsec for output to recover to within 15mV following a change in output from full load to half load or vice versa.

Setting time

Less than 90msec for the output voltage to change from 1% to 99% or vice versa following the receipt of VOLTAGE or SET command via RS-232 interface

OVP Accuracy, ± (% of output + offset) < 50mV

Activation time: Average time for output to start to drop after OVP condition occurs .

≤ 1.2 msec

Supplemental Characteristics

Remote sensing capability

Voltage drop Up to 1V per each lead Load regulation Add 5mV to spec for each 1-volt change in the + outputs

lead due to load current change.

Load voltage Substract voltage drop in load leads from specified output

voltage rating.

Temperature coefficient, ±(% of output+offset)

Maximum change in output/readback per Voltage < 0.02%+2mV

Current < 0.1%+1mA

Output voltage overshoot

During turn -on or turn -off of AC power, output plus overshoot will not exceed 1V if the output control is set to less than 1V. If the output control is set to 1V higher, there is no overshoot.

Programming language

SCPI (Standard Commands for Programmable Instruments)

State storage memory:

100 user configurable states

Recommended calibration interval:

1 year

Output terminal isolation (maximum, from chassis ground):

±60 Vdc when connecting shorting conductors without insulation between the (+) output and the (+) sense terminals and between the (-) output and the (-) sense terminals. ±240 Vdc when connecting insulated shorting conductors between the(+) output and the (+) sense terminals and between the (-) output and the (-) sense terminals.

C after a 30-minute warm-up:

AC Input Ratings (selectable via the line voltage receptacle switch):

115 Vac ± 10 % for 47 to 63 Hz 230 Vac ± 10 % for 47 to 63 Hz

Line voltage selection:

The line fuse is located in the sp ace just below the input receptacle. To chang e line voltage values first remove fuse holder and then remove tan colored fuse bracket. The line voltage value is determined by value shown through the window of the fuse holder. Please ensure correct insertion and fuse rating.

Fuse ratings:

Model 9120: 3.15A/250V for 115Vac, 2A/250V for 230V Model 9121: 3.15A/250V for 115Vac, 2A/250V for 230V Model 9122: 5A/250V for 115Vac, 3.15A/250V for 230V All fuses are type T (temporized) for high power up currents.

Cooling:

Fan cooled

Operating temperature:

32° to +104° F (0° to 40° C), <75% R.H. for full rated output.

Storage temperature:

-4° to +158° F (- 20° to + 70° C), <85%R.H. for storage environment.

Environmental conditions:

Designed for indoor use.

Net weight:

12.5 (5.6 kg)

Dimensions (H x W x D):

3.15 x 8.27 x 15” (8 x 21 x 38 cm)

Important note!

The technical specification are warranted for 32° to 104°F (0

to 40°C) with a resistive load. Supplemental characteristics are not warranted. They are determined either by testing or design.

Programming Ranges

The power supply parameters are programmed using command of SOURce subsystem. Here are programming ranges, programming values for MINimum, MAXimum, DEFault parameters and reset state:

Table 4: Programming ranges for voltage parameter

Voltage parameters Model 9120 Model 9121 Model 9122

Programming range 0 to 30.5 V 0 to 20.5 V 0 to 60.5 V MINimum 0 V 0 V 0 V MAXimum 30.5 V 20.5 V 60.5 V DEFault 0 V 0 V 0 V Reset 0 V 0 V 0 V

Table 5: Programming ranges for current parameter

Current parameters Model 9120 Model 9121 Model 9122

Programming range 0 to 3.05 A 0 to 5.05 A 0 to 2.55 A MINimum 0 A 0 A 0 A MAXimum 3.05 A 5.05 A 2.55 A DEFault 0 A 0 A 0 A Reset 3.00 A 5.00 V 2.5 V

Table 6: Programming ranges for OVP parameter

OVP parameter Model 9120 Model 9121 Model 9122

Programming range 1 to 33 V 1 to 22 V 1 to 63 V MINimum 1V 1V 1V MAXimum 33 V 22 V 63 V Reset 33 V 22 V 63 V

Important note!

Reset value for a parameter is the value after a *RST command or after recalling Reset state.

Reset values

Here are the power supply parameter values after a *RST command or after recalling Reset state.

Table 7: Reset values for power supply parameters

Power supply

parameters

V oltage 0 V 0V 0V Voltage step 0.01 V 0.01 V 0.01 V Voltage trigger 0 V 0 V 0 V OVP circuit state ON ON ON OVP trip level 33 V 22 V 63 V Current 3.00 A 5.00 A 2.50 A Current step 0.001 A 0.001 A 0.001 A Current trigger 3.00 A 5.00 A 2.50 A Display state ON ON ON Output state OFF OFF OFF Trigger delay 0 s 0 s 0 s Trigger source BUS BUS BUS

Model 9120 Model 9121 Model 9122

Interface Cable

DTR

GND

DB -9

Instrument

DTR

GND

DB-9

In order to command the power supply over the remote interface, you must connect it to a computer terminal.

Usually, the computer terminals are DTE (Data Terminal Equipment). The power supply is also DTE, so you need a DTE to DTE interface cable. These cables are called null-modem or crossover cables.

There are 2 types of serial connectors: DB-9 and DB -25. The power supply has a male DB-9 connector.

Here is cable pin diagram for DB-9 connector:

DSR

connector

2 3 4 5 6

DSR

connector

The rest of the pins are not connected.

If the serial port from your PC has a DB -25 connector, you must use a DB-25 to DB-9 adapter.

Limited One-Year Warranty

B&K Precision Corp. warrants to the original purchaser that its product and the component parts thereof, will be free from defects in workmanship and materials for a period of one year from the data of purchase.

B&K Precision Corp. will, without charge, repair or replace, at its’ option, defective product or component parts. Returned product must be accompanied by proof of the purchase date in the form a sales receipt.

To obtain warranty coverage in the U.S.A., this product must be registered by completing and mailing the enclosed warranty card to B&K Precision Corp., 22820 Savi Ranch Parkway, Yorba Linda, CA 92887 within fifteen (15) days from proof of purchase.

Exclusions: This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alternations or repairs. It is void if the serial number is alternated, defaced or removed.

B&K Precision Corp. shall not be liable for any consequential damages, including without limitation damages resulting from loss of use. Some states do not allow limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you.

This warranty gives you specific rights and you may have other rights, which vary from state-to-state.

Model Number: ______________ Date Purchased: __________

22820 Savi Ranch Parkway

Yorba Linda, CA 92887

714.921.9095

714.921.6422 Facsimile

Service Information

Warranty Service: Please return the product in the original packaging with

proof of purchase to the below address. Clearly state in writing the performance problem and return any leads, connectors and accessories that you are using with the device.

Non-Warranty Service: Return the product in the original packaging to the below address. Clearly state in writing the performance problem and return any leads, connectors and accessories that you are using with the device. Customers not on open account must include payment in the form of a money order or credit card. For the most current repair charges contact the factory before shipping the product.

Return all merchandise to B&K Precision Corp. with pre -paid shipping. The flat-rate repair charge includes return shipping to locations in North America. For overnight shipments and non -North America shipping fees contact B&K Precision Corp..

B&K Precision Corp. 22820 Savi Ranch Parkway Yorba Linda, CA 92887 Phone: 714- 921 -9095 Facsimile: 714-921-6422 Email: service@bkprecision.com

Include with the instrument your complete return shipping address, contact name, phone number and description of problem.

22820 Savi Ranch Parkway

PN: 481-533-9-001 Printed in Romania 2004 B&K Precision Corp.

Yorba Linda, CA 92887 USA TEL: 714 -921-9095 FAX: 714-921-6422

www.bkprecision.com

BK Precision 9120, 9121, 9122 Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual