BK Precision 9120, 9121, 9122 Instruction Manual

Model 9120, 9121 & 9122
Instruction Manual
SINGLE OUTPUT PROGRAMMABLE DC POWER SUPPLY
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
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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
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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)
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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.
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6
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.
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.
By pressing Memory key, you enter in Memory menu. By turning the knob following options will be displayed:
Store State
Name State
Exit
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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.
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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).
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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
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.
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.
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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
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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.
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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:
U
I
= 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).
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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.
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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.
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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.
U
out
R
Let’s consider a resistor connected to the output terminals of the power supply (R resistor). Limit (programmed) values are:
U
=5V
lim
I
=2A
lim
U
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.
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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.
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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
I
), 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
lim
< U
< I
out
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
R
resistor is connected between (-) and (+) terminals of the power supply.
load
resist or to the output terminals
load
lim
and
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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.
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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
I
), 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
U
lim
lim
< U
< I
out
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
R
resistor is connected between (-) and (+) terminals of the power supply.
load
resistor to the output terminals
load
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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.
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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 .
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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.
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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
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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.
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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.
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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).
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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).
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