SEFRAM 4451 50 MHz PROGRAMMABLE PULSE GENERATOR OPERATING MANUAL
Operating Manual M4451 A00 SEFRAM 4451 2
Operating Manual SEFRAM 4451 INDEX Page SAFETY SUMMARY Section Section Section Section M4451 A00 1 General Information 5 1.1 1.2 1.3 1.4 Introduction Description Safety Remarks Specifications 8 8 8 9 2 Installation 2.1 2.3 2.4 2.5 2.6 2.7 2.8 Introduction Initial Electrical Inspection Instrument Mounting Power Requirements Grounding Requirements Signal Connections GPIB Connections 3 Operating Instructions 3.1 3.6 3.10 3.12 3.
Operating Manual Section M4451 A00 SEFRAM 4451 5 Performance Check Procedure 66 5.1 5.2 5.3 5.
Operating Manual SEFRAM 4451 Safety Summary The following safety precautions apply to both operating and maintenance personnel and must be observed during all phases of operation, service, and repair of this instrument. Before applying power, follow the installation instructions and become familiar with the operating instructions for this instrument.
Operating Manual SEFRAM 4451 WARNING: To avoid electrical shock hazard, disconnect power cord before removing covers. Refer servicing to qualified personnel. CAUTION: Before connecting the line cord to the AC mains, check the rear panel AC line voltage indicator. Applying a line voltage other than the indicated voltage can destroy the AC line fuses. For continued fire protection, replace fuses only with those of the specified voltage and current ratings.
Operating Manual M4451 A00 SEFRAM 4451 7
Section 1 General Information 1.1 Introduction This manual contains information required to operate, program, check and maintain the SEFRAM 4451 - 50 MHz PROGRAMMABLE PULSE GENERATOR. 1.2 Description The SEFRAM 4451 is a high performance programmable pulse generator. The instrument generates pulses with a repetition rate to 50MHz, width from 10ns, variable delay, variable transition times and amplitude.
Operating Manual 1.4 SEFRAM 4451 SPECIFICATIONS The following specifications describe the instrument performance after a 20 minute warm-up period into a 50 ohms load. All timing characteristics are measured at 50% of amplitude with fastest edges. PULSE FUNCTIONS Single - One pulse at each selected period up to 50MHz repetition rate. Double - One pair of pulses at each period up to 25MHz repetition rate.
Operating Manual SEFRAM 4451 Range - 10ns to (Period - 10ns off time). Resolution - Up to 6 digits, limited to 100 ps. Accuracy - ±(0.5% of setting +500 ps) Double Pulse: - ±(0.5% of setting +3 ns) for the second pulse. DELAY Range - 0ns to (Period – Width - 10ns off time). Resolution - Up to 6 digits, limited to 100 ps. Accuracy - ±(0.5% of setting +500 ps) DUTY CYCLE Range -1 to 99%. Resolution -3 digits (0.1%). Accuracy: -Limited by width and pulse accuracy.
Operating Manual SEFRAM 4451 100ns; 50ns-1.0us; 500ns-10us; 5.0us-100us; 50us-1.0ms; 500us-10ms, 5 ms – 100 ms. Resolution - 3 digits limited to 10 ps. Accuracy - ±(5% of setting +2ns) Linearity - <5% deviation from a straight line between 10% and 90% points, for transitions > 50 ns. INTERNAL TRIGGER Range - 100ns to 100s. Resolution - 4 digits limited to 100ns. Accuracy - ± 0.01% INPUT AND OUTPUT TRIGGER INPUT Sensitivity - 200 mVp-p minimum. Minimum Width - 10ns.
Operating Manual SEFRAM 4451 GPIB PROGRAMMING Internal - IEEE-488.2 and SCPI compatible. Address - 0-30 front panel selected. Subsets - SH1, AH1, T6, L4, SR1, RL1, PP0, DC1,DT1, C0, E2. GENERAL -Non volatile, stores up to 99 complete panel settings. Last user setup also retained at power down. Memory Power Requirements - 100-240V, ±10%, 48-66 Hz, 50VA maximum. Dimensions - Height 8.8cm, Width 21.3 cm, Length 30 cm Weight - Aprox 3kg Net.
Operating Manual M4451 A00 SEFRAM 4451 13
Operating Manual SEFRAM 4451 Section 2 Installation 2.1 Introduction This section contains installation information, power requirements, initial inspection and signal connections for the SEFRAM 4451. 2.2 Initial Mechanical Inspection Upon receipt, inspect the instrument for any damage that might have occurred in transit and verify the contents of the shipment (accessories and installed options). 2.3 Initial Electrical Inspection The SEFRAM 4451 is calibrated and ready for use when received.
Operating Manual SEFRAM 4451 2.6 Grounding Requirements To minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical ground. This instrument is grounded through the ground conductor of the supplied, three-conductor ac power cable. The power cable must be plugged into an approved three-conductor electrical outlet. WARNING: Do not alter the ground connection.
Operating Manual SEFRAM 4451 2.7.2 Impedance Matching A mismatch, or different impedance in a transmission line, generates a reflection back along the line to the source. The amplitude and polarity of the reflection are determined by the load impedance in relation to the characteristic impedance of the cable. If the load impedance is higher than the characteristic impedance of the line, the reflection will be of the same polarity as the applied signal.
Operating Manual SEFRAM 4451 For example: to match a 50Ω system to a 125Ω system, Z1 equals 50Ω and Z2 equals 125Ω Therefore: R1 = 125(125 − 50) = 96.8 Ω and R2 = 50 125 = 64.6 Ω 125 − 50 Although the illustrated network provides minimum attenuation, for a purely resistive impedance-matching device, the attenuation as seen from one end does not equal that seen from the other end.
Operating Manual SEFRAM 4451 than the combined rise times of the testing system, determine the actual rise time of the device under test by using the following formula: Rt = (Rt 1) 2 + (Rt 2 ) 2 + (Rt 3) 2 + ...... Rt equals the overall rise time or fall time of the entire measurement system and R1, R2, R3, etc. are the rise times or fall times of the individual components in the system. 2.
Operating Manual SEFRAM 4451 DB-9 pin Name 1 2 3 4 5 6 7 8 9 N/C RXD TXD N/C GND N/C RTS CRS N/C Note Computer DB25 pin 8 3 2 7 6 4 5 - Receive Data Transmit Data Signal ground Request to Send Clear to send - Direction In In Out Out In Out In - 2.10 RS-232 Configuration Before connecting the RS-232 interface, the instrument must be properly configured. Select UTILITY menu and then F4 - RS232 for setting of the desired baud date.
Operating Manual M4451 A00 SEFRAM 4451 20
Section 3 Operating Instructions 3.1 General Description This section describes the displays, controls and connectors of the SEFRAM 4451 Pulse Generator. All controls for the instrument local operation are located on the front panel. The connectors are located on both front and rear panels. Figure 3.1 - SEFRAM 4451 Front Panel 1. Power ON-OFF -Applies and removes AC power to the unit. 2. Display Window -Displays all instrument data and settings on a LCD. 3.
Operating Manual SEFRAM 4451 output, parameter or mode displayed selected. 3.3 Front Panel Controls The front-panel controls select, display, and change parameter, function, and mode settings. Use the rotary input knob and the cursor movement keys to enter data into the pulse generator. To change a setting: 1. Press the key that leads to a required item. 2. Move cursor using cursor keys to the appropriate position in the numeric field. 3.
Operating Manual SEFRAM 4451 3.6 MENU Keys These keys select the main menus for displaying or changing a parameter, function or mode. 3.6.1 PARAM Menu This key selects and displays the pulse timing parameters, the double pulse mode and allows changing the parameter data. Parameter Menu F1: PERIOD/FREQ - Selects and displays the period or the pulse frequency. Change the value using the shift keys, rotary knob or numerical keys.
Operating Manual F3: DELAY SEFRAM 4451 - This parameter is used in two instances. The first is to set the delay of the pulse in the single pulse mode. The delay governs the time from the SYNC signal to the start of the pulse. The second instance is the double pulse mode. Here the delay governs the time from the SYNC pulse to the second pulse. The minimum and maximum values of the delay are dependent on the values of the period, width and leading and trailing edge times. The delay range is 0 to 9.80000s.
Operating Manual SEFRAM 4451 OUTPUT Menu F1: HILVL - Selects the pulse high level voltage. F2: LOLVL F3: PREDEF - Selects the pulse low level voltage. - Selects the predefine pulse output levels. In addition to being able to set the levels to any value within the limits, the user may also select one of four pre-defined levels: CMOS: Low level (LOLVL) = 0V, High level (HILVL) = 5V TTL: Low level (LOLVL) = 0.4V, High level (HILVL) = 2.4V ECL: Low level (LOLVL) = -1.8V, High level (HILVL) = -0.
Operating Manual 3.6.3 SEFRAM 4451 PULSE Menu PULSE Menu F1: RISE - Selects the pulse Rise time (Leading edge). F2: FALL - Selects the pulse Fall time (Trailing edge). F3: EQUAL - Selects equal Rise (Leading edge) and Fall (Trailing edge) times. F5: NORMAL/COMPL - Selects the Normal or Complement pulse mode. COMPLEMENT Pulse Mode The transition time range is 5ns to 100ms, but the value is limited to a 20:1 ratio between the transition times.
Operating Manual SEFRAM 4451 3.6.4 MODE Menu Selects the output mode: CONT (Continuous), TRIG (Triggered), GATE (Gated), BRST (Burst) and PHASE. To select the output mode, press MODE, then press the function key that corresponds to the desired Mode menu option, as shown: Mode Menu F1: CONT - (Continuous) - Selects continuous output. F2: TRIG - (Triggered) - Triggers one output cycle of the selected pulse for each trigger event.
Operating Manual SEFRAM 4451 Trigger Menu F1: MAN - Selects manual as the trigger source. Pressing the MAN TRIG key generates the trigger. In the Gate trigger mode, the pulse is generated as long as the key is being pressed. F2: INT - Selects the internal trigger generator as the trigger source. Change the internal trigger rate displayed with the rotary input knob or numerical keys. The rate has a range of 100ns to 99.
Operating Manual SEFRAM 4451 SETUPS Menu F1: RECALL - Recalls a previously stored front-panel setup from the selected buffer. Change the buffer number by using the rotary input knob. Valid storage buffer numbers are from 1 to 99. Buffer 0 is the factory default setup; buffer 99 is the last front panel setup before power-off. F2: STORE - Stores the current front-panel setup to the specified storage buffer. Change the buffer number by using the data keys or the rotary input knob.
Operating Manual SEFRAM 4451 GPIB Menu F2: RS232 -Selects the RS232 remote control mode. After selection, the baud rate can be selected as 1200, 2400, 9600, 19200, 38400, 57600 or 115K. Always the RS-232 uses 8 bit data, 1 stop bit and no parity. F3: INTEN - Selects the intensity of the LCD display. Select a value using the rotary input knob. Valid numeric values are from 1 to 31. The value is kept in the nonvolatile memory, after a 20 seconds time-out.
Operating Manual SEFRAM 4451 When the pulse generator finishes the diagnostic self-test routine, it enters the local state (LOGS) and assumes power-on default settings if the POWER-ON setting is at 0. You can program the pulse generator for any settings you want at power on, as described earlier in this section.
Operating Manual SEFRAM 4451 Error messages for SEFRAM 4451 Message Text Cause Setting conflict Trig rate short Empty location Calibration Error LCA load error Output overload Verify unit calibration Can't have this parameter set with other parameters. Internal trigger rate too short for pulse or burst. Attempt to restore a non existent setting. An error when performing unit calibration – for service personnel only.
Operating Manual SEFRAM 4451 SETTLING TIME is the interval required for the pulse level to enter and remain in the specified level ACCURACY RANGE, measured from the 90% AMPLITUDE point. 3.13 Pulse Parameter Limitations The following formulas express the limits on Period, Width, and Delay. Single Pulse per Period Modes (Un-delayed, Delayed, Counted Burst with single pulse mode) [Period - (Width + Delay)] must be > 10 ns 0.
Operating Manual SEFRAM 4451 (0.
Operating Manual M4451 A00 SEFRAM 4451 35
Operating Manual M4451 A00 SEFRAM 4451 36
Section 4 Programming 4.1 OVERVIEW This section provides detailed information on programming the SEFRAM 4451 via the IEEE 488 bus (GPIB - General Purpose Interface Bus). The SEFRAM 4451 is programmable over the IEEE 488 bus, and its message protocol is compatible with IEEE 488.2. The device command set is compatible with the SCPI 1992.0 standard. The SCPI standard does not cover all the needs of the SEFRAM 4451, and so the standard has been added where necessary.
Operating Manual SEFRAM 4451 Setting the device to address 31 puts it in the 'off-bus' state. In this state it will not respond to messages on the GPIB. If the device is in the REMS when set to address 31, an internal 'returnto-local' command will be given, setting the device to the LOCS. If the device is in the RWLS, the 'return-to-local' command is ignored, and the device remains in the RWLS.
Operating Manual 4.9.1 SEFRAM 4451 General Command Structure The device commands are generally defined by the SCPI standard, with the exception of those instrument functions for which SCPI commands do not as yet exist. The Common Commands and Queries are defined by IEEE 488.2. The command syntax, i.e. how a command is structured, is defined by IEEE 488.2. 4.9.
Operating Manual SEFRAM 4451 The Program Data represent the values of the parameters being set, for example, the '1US' in the above examples. Different forms of program data are accepted, depending on the command. The Program Data types used in the SEFRAM 4451 are as follows: 1. Character program data – This form of data is comprised of a mnemonic made up of lower - or upper-case alpha characters. As with Program Header mnemonics, some Character Data mnemonics have short and long forms.
Operating Manual SEFRAM 4451 SOURCE:FREQUENCY 3KHZ;:OUTPUT:STATE ON Common Commands may be inserted in the Program Message without affecting the instrument-control command reference. For example, SOURCE:VOLTAGE:HIGH 4V;*ESE 255;LOW 2V 4.10 STATUS REPORTING The instrument is capable of reporting status events and errors to the controller, using the IEEE 488.1 Service Request function and the IEEE 488.2 Status Reporting structure. 4.10.
Operating Manual SEFRAM 4451 Bit 3: Device-Specific Error (DDE). This bit is set to indicate that a device operation did not execute due to some device condition. Bit 4: Execution Error (EXE). This bit is set when the device could not execute a command, due to the command being outside of it's capabilities. For example, a parameter being out of range. Bit 5: Command Error (CME). This bit is set to indicate an error in the command syntax. Bit 6: User Request (URQ).
Operating Manual SEFRAM 4451 4.10.5.1 Command Errors A command error is in the range -199 to -100, and indicates that a syntax error was detected. This includes the case of an unrecognized header. The occurrence of a command error causes the CME bit (bit 5) of the Standard Event Status Register to be set.
Operating Manual SEFRAM 4451 A query error indicates that the output queue control has detected a problem. This could occur if either an attempt was made to read data from the instrument if none was available, or when data were lost. Data could be lost when a query causes data to be formatted for the controller to be read, and the controller sends more commands without reading the data.
Operating Manual SEFRAM 4451 4.11.3 Synchronization Commands 4.11.3.1 *OPC - Operation Complete Command The operation complete command causes the device to generate the operation complete message in the Standard Event Status Register, on completion of the selected device operation.
Operating Manual SEFRAM 4451 COMMAND TYPE: Common Command or Query Syntax: *ESR? Response: 4.11.4.4 *PSC - Power-On Status Clear Command This command is used to control the automatic power-on clearing of certain status functions.
Operating Manual SEFRAM 4451 Syntax: *TRG 4.11.6 Stored Settings Commands 4.11.6.1 *RCL - Recall Instrument State This command is used to restore the state of the device to that stored in the specified memory location. COMMAND TYPE: Common Command Syntax: *RCL Arguments: Type: Range: Example: 0 to 99. Non integer values are rounded before execution *RCL 0 (Recall default state) *RCL 99 4.11.6.
Operating Manual SEFRAM 4451 :DOUBle [:STATe] :DELay :TRANsition [:LEADing] :TRAiling :AUTO |ONCE :POLarity NORMal|COMPlement|INVerted 4.12.1.1 Frequency The frequency command controls the frequency of the pulse in the continuous trigger mode. It is the inverse of the period. COMMAND TYPE: Setting or Query SETTING Syntax: [:SOURce]:FREQuency[:CW|FIXed][units] Arguments: Type: Units: Range: Rounding: Examples: NRf MHz, kHz, Hz (default) 0.
Operating Manual SEFRAM 4451 This command is used to set the low level of the pulse. COMMAND TYPE: Setting or Query SETTING Syntax: [:SOURce]:VOLTage[:LEVel][:IMMediate]:LOW[units] Arguments: Type: Units: Range: Rounding: Examples: NRf MV, V (default) -10V to +9.5V To 10mV :VOLT:LOW 4V QUERY Syntax: [:SOURce]:VOLTage:[:LEVel][:IMMediate]:LOW? Examples: :VOLT:LOW? Response: NRf CONSIDERATIONS: 1) The high level must be greater than the low level.
Operating Manual SEFRAM 4451 QUERY Syntax: [:SOURce]:VOLTage[:LEVel][:IMMediate]:PLOW? Examples: :VOLT:PLOW? Response: NRf 4.12.1.6 Predefined Voltage Levels This command is used to set the pulse voltage levels to predefined values. Four predefined values are available as follows: CMOS: TTL: ECL: USER: High level 5V; Low level 0V High level 2.4V; Low level 0.4V High level –0.8V; Low level –1.
Operating Manual SEFRAM 4451 QUERY Syntax: [:SOURce]:VOLTage:LIMit:LOW? Examples: :VOLT:LIM:LOW? Response: NRf CONSIDERATIONS: The low limit cannot be set greater than the low level. 4.12.1.9 Pulse Period This command is used to set or query the period of the pulse.
Operating Manual SEFRAM 4451 4.12.1.11 Pulse Delay This command is used to set the delay from the trigger signal to the start of the pulse in single pulse mode. Although there exists a separate command for the double pulse delay, both commands affect the same delay, and so this command will also determine the time between the two pulses in the double pulse mode.
Operating Manual SEFRAM 4451 SETTING Syntax: [:SOURce]:PULSe:HOLD
Operating Manual SEFRAM 4451 This command is used to set the delay of the second pulse, from the time of the trigger, in the double pulse mode. It has exactly the same effect as the :PULSE:DELAY command, and is included in the command set for compatibility purposes. COMMAND TYPE: Setting or Query SETTING Syntax: [:SOURce]:PULSe:DOUBle:DELay[units] Arguments: Type: NRf Units: S (seconds), MS (milliseconds), US (microseconds), NS nanoseconds Range: 0NS to 9.
Operating Manual SEFRAM 4451 4.12.1.18 Trailing Edge Time This command is used to set the value of the trailing edge time. If the edge-tracking feature is ON, changing the trailing edge will cause the same change in the leading edge. Refer to 2.1.19 for the tracking control command.
Operating Manual SEFRAM 4451 This command is used to control the polarity of the pulse, which may be normal or complemented. The COMPement and INVerted parameters are aliases: either may be used.
Operating Manual SEFRAM 4451 :BURSt :SOURce | INTernal | EXTernal | BUS :TIMer :LEVel :DELay :SLOPe POSitive | NEGative 4.12.3.1 Trigger Mode This command is used to set the trigger mode. It is not a standard SCPI command.
Operating Manual SEFRAM 4451 QUERY Syntax: :TRIGger:BURSt? Response: NRf Examples: :TRIG:BURSt? 4.12.3.4 Internal Trigger Rate Sets the rate of the internal trigger. COMMAND TYPE: Setting or Query SETTING Syntax: :TRIGger:TIMer[units] Arguments: Type: NRf Units: S (seconds), MS (milliseconds), US (microseconds), NS nanoseconds Range: 100NS to 99.
Operating Manual SEFRAM 4451 Syntax: :TRIGger:SLOPe? Examples: :TRIG:SLOP? Response: POS | NEG 4.12.4 Status Subsystem This subsystem controls the SCPI-defined status reporting structures, which are the QUEStionable and OPERation status registers, and the error/event queue. The QUEStionable and OPERation status registers are mandated by SCPI, and so are implemented, but are not used by the hardware. No status is ever reported through them, and they are not detailed in this manual.
Operating Manual SEFRAM 4451 Communication with the instrument can be resumed only by setting the address to a suitable value from the front panel. COMMAND TYPE: Setting or Query SETTING Syntax: :SYSTem:COMMunicate:GPIB:ADDRess Arguments: Type: Range: Rounding: Examples: NRf 0 to 31 To integer value :SYST:COMM:GPIB:ADDR 20 QUERY Syntax: :SYSTem:COMMunicate:GPIB:ADDRess? Examples: :TRIG:SLOP? Response: in NR1 format 4.12.5.
Operating Manual SEFRAM 4451 COMMAND TYPE: Setting or Query SETTING Syntax: :SYSTem:POBuffer Arguments: Type: Range: Rounding: Examples: Numeric 0 to 99 To integer value :SYST:POB 99 QUERY Syntax: :SYSTem:POBuffer? [MINimum | MAXimum] Response: Power-on buffer in NR1 format. 4.13 IEEE 488.1 INTERFACE MESSAGES 4.13.1 GET - Group Execute Trigger The GET is used by the SEFRAM 4451 as a trigger when it is in either the TRIGGER, GATE or BURST modes, with the trigger source set to BUS.
Operating Manual SEFRAM 4451 4.14 SCPI COMMAND TREE 4.14.1 Root Node Root [:SOURce] :OUTPut :TRIGger :STATus :SYSTem 4.14.
Operating Manual SEFRAM 4451 4.14.4 TRIGger Subsystem :TRIGger :BURSt :TIMer :LEVel :SLOPe POS | NEG :MODE :SOURce CONT | TRIG | GATE | BURS INT | EXT | MAN | BUS 4.14.5 STATus Subsystem :STATus :OPERation :PRESet :QUEue [:NEXT]? [:EVENt]? :CONDition? :ENABle :PTRansition :NTRansition :OPERation [:EVENt]? :CONDition? :ENABle :PTRansition :NTRansition 4.14.
Operating Manual SEFRAM 4451 :SYSTem :COMMunicate :GPIB :ADDRess :ERRor? :SECurity [:STATe]? ON | OFF M4451 A00 62 :POBuffer :VERSion?
Operating Manual 4.
Operating Manual SEFRAM 4451 4.15.1 General The INSTALLATION section of this manual describes the RS-232-C connection for the instrument. Be sure that you have the Remote Mode set to RS-232 and correctly set the baud rate. EIA standard RS-232-C specifies the electrical characteristics and pin out of a serial communication standard for connecting "data terminal equipment" (DTE) to "data communication equipment" (DCE).
Operating Manual M4451 A00 SEFRAM 4451 65
Operating Manual SEFRAM 4451 Section 5 Performance Check Procedure 5.1 Introduction This section contains the test procedures required to check the electrical performance as listed in the SPECIFICATIONS section of this manual (1.4). The checkout procedure is recommended for preliminary incoming inspection and operational control. 5.2 Test Equipment The following table lists the equipment necessary to perform the performance tests. Any equivalent equipment may be substituted for the recommended model.
Operating Manual SEFRAM 4451 The following tests are intended to verify that the SEFRAM 4451 operates properly and meets its specifications. Perform the tests after a warm-up period of 30 minutes, at 25°C + 5°C ambient temperature. These tests may be used for periodic inspection and after repair. If the instrument does not meet its specification, please contact the SEFRAM service center. Period Accuracy Test SPECIFICATION - ± 0.01%.
Operating Manual SEFRAM 4451 input with a 50Ω termination. Select leading and trailing times. CHECK - The Rise and Fall times measured between 10% and 90% points are within specification. SPECIFICATION - ± (1% of setting +10mV) into 50Ω. PROCEDURE - Connect the instrument OUTPUT to the oscilloscope input with a 50Ω termination. Change the high and low levels to obtain different signal amplitudes. Select a period of 100us. CHECK - The signal amplitude measured is within specification.
Operating Manual SEFRAM 4451 To contac us : SEFRAM Instruments et Systèmes 32, rue E. MARTEL BP55 F 42009 – SAINT-ETIENNE cedex 2 France Tel : 0825 56 50 50 (0,15€TTC/mn) Fax : 04 77 57 23 23 E-mail : sales@sefram.fr Web : www.sefram.
Operating Manual SEFRAM 4451 DECLARATION OF CE CONFORMITY according to EEC directives and NF EN 45014 norm DECLARATION DE CONFORMITE CE suivant directives CEE et norme NF EN 45014 SEFRAM INSTRUMENTS & SYSTEMES 32, rue Edouard MARTEL 42100 SAINT-ETIENNE ( FRANCE) Declares, that the below mentioned product complies with : Déclare que le produit désigné ci-après est conforme à : The European low voltage directive 73/23/EEC : NF EN 61010-1 Safety requirements for electrical equipment for measurement, contr
