Bnc 1201 - 6 1/2 Digit Digital Multimeter Manual de usuario

1201 6 ½ Digit Multimeter User’s Manual Printed Date: 04/2008

11 This symbol indicates “Protective Conductor Terminal”. This symbol indicates earth (ground) terminal. This symbol indicates this produ

101(Slow 5.5 & Fast 6.5) 1 105 19.0 (Slow 6.5) 10 408 4.9 NPLC Take Time with 2000 Readings(sec) rate(ch/s) (Fast 4.5) 0.02 3

102 The locations of the buttons are shown with red rectangle frames in Figure 4-31. Figure 4-31 4.4.6 Stepping (Step) Stepping is s

103STORE option, you can select ON to instruct the meter to store the measurement results for later retrieving or select OFF. Press ENTER

1047 MX+B Values: M, B 8 Reading Hold Sensitivity Band 9 Input R DC Input Resistance 10 Interface USB、GPIB ADDR、RS232 baud & parity 11 Sy

105 Figure 4-34 4.4.9 Error Condition The error annunciator on the front panel display tells about the error condition of the multimeter.

106 Figure 4-35 4.4.10 Firmware Revision 1201 has three microprocessors for various internal systems. You can query the multimeter to determine

107 4.4.11 Calibration 1201 will show the latest calibrated date and the next calibration date on the display after following the operation

108 Warning! Erroneous self-test failures may occur if the setting of power line voltage is incorrect. Errors may also occur because of signals

109Communication must function in both directions for this test to pass. 602 RAM read/write failed This test writes and reads a 55h and AAh checker

110input. The 500nA ohms current source is connected to produce a nominal 5V signal. A 20ms ADC measurement is performed and the result is

Material: Probe Body: Outer Insulation-Santoprene Rubber. Banana Plug: Body Brass, Nickel Plated Spring Beryllium Copper, Nickel Plated. Insulation: P

111 619 Ohms 1 mA source failed his test configures to the 1000V dc range with the internal 10M 100:1 divider R204 connected across the inp

1125 Remote Interface Operations 1201 supports two remote interfaces: the built-in USB and optional GPIB (IEEE-488). With GPIB, you will need a GPIB

113Number Assignment 1 VBUS Red Floating 2 D- White Limit Test Pass 3 D+ Green Limit Test Fail 4 GND Black GND Table 5-1 If you disable

114※ Note: The icons, pictures and words will be changed or edited with different versions without informing. Figure 5-1

115 automatically sets the other parameters for you, make the measurement and send the result to the output buffer. MEASure: VOLTage:DC? {<range&

116DIODe TCOuple TEMPerature CONFigure? The READ? Command The READ? Command changes the state of the trigger system from the “idle” state to

117 [SENSe:] FUNCtion “VOLTage:DC” FUNCtion “VOLTage:DC:RATio” FUNCtion “VOLTage:AC” FUNCtion “CURRent:DC” FUNCtion “CURRent:AC” FUNCtion “RESistance

118 VOLTage:AC:RANGe:AUTO {OFF|ON} VOLTage:AC:RANGe:AUTO? CURRent:DC:RANGe:AUTO {OFF|ON} CURRent:DC:RANGeAUTO? CURRent:AC:RANGe:AUTO {OFF|ON} CURRent

119TCOuple:RJUNction:SIMulated? TCOuple:RJUNction:REAL:OFFSet {<value>|MINimum|MAXimum} TCOuple:RJUNction:REAL:OFFSet? [MINimum|MAXimum] [SENS

120FRESistance:NPLCycles {0.02|0.1|1|10|MINimum|MAXimum} FRESistance:NPLCycles? [MINimum|MAXimum] [SENSe:] FREQuency:APERture {0.01|0.1|1|MINimum|MA

13 1.9 1201’s Dimension Please get the dimension’s information in the following different ways. 1. The dimension without the handle and the fron

121ROUTe:OPEN ROUTe:STATe? ROUTe:SCAN:FUNCtion <channel>,{<function>|“VOLT:DC”|“VOLT:AC”| “FREQuency”|“RESistance”|“FRESistance”|“NON

122AVERage:AVERage? AVERage:COUNt? CALCulate: NULL:OFFSet {<value>|MINimum|MAXimum} NULL:OFFSet? [MINimum|MAXimum] CALCulate: LIMit:LOWer {<

123accept the trigger. The multimeter takes immediate internal trigger, a software trigger from a remote interface and external trigger from the rear

124Each system related operation performs a task that is not measurement related but plays an important role in making your measurements. FETCh? REA

125STATUS REPORTING Commands SYSTem:ERRor? STATus: QUEStionable:ENABle <enable value> QUEStionable:ENABle? QUEStionable:EVENt? STATus:PRESet

126*RST *SRE <enable value> *SRE? *STB? *TRG

1276 Error Messages Errors are retrieved in first-in-first-out (FIFO) order. The first error returned is the first error that was stored. W

128 -104 Data type error A parameter type error was found in the command string. -105 GET not allowed A Group Execute Trigger (GET) is not allow

129 -148 Character not allowed A discrete parameter was received but a character string or a numeric parameter was expected. -151 Invalid string

130 -222 Data out of range A numeric parameter value is out of range. -223 Too much data A character string was too long. -224 Illegal parame

14 2 Overview This chapter will give you an overview of 1201’s basic features and guide you through the basics of 1201 digital multimeter. Users

131 531 Insufficient memory There is not enough memory to store the requested number of readings in internal memory using the INITiate command.

132Appendix This appendix contains the performance specifications of the 1201. It covers the AC, DC, Resistance, Temperature, and Freque

133Function Range Resolution Shunt Resistance 1 Year (23°C ± 5°C) 10.000000mA 10 nA 5.1Ω 0.050 + 0.020 100.00000mA 100 nA 5.1Ω 0.050 + 0.005 1.0

134Frequency and Period Characteristics Accuracy ± (% of reading)5 Function Range6 Frequency (Hz) 1 Year 23º C±5º C 3-5 0.10 5-10 0.05 10-40 0.

13510-20K 0.06 + 0.04 20-50K 0.12 + 0.05 50K – 100K 0.60 + 0.08 100K – 300K 4.00 + 0.50 3-5 1.00 + 0.03 5-10 0.35 + 0.03 10-20K 0.06 + 0.03 20-50K

136 B. General Specifications item Limitation & description Power Supply 100V/120V/220V/240V ± 10% Power Line Frequency 50~60 Hz ± 10% Power

137 C. Remote Interface Reference C.1 An Introduction to the SCPI Language SCPI (Standard Commands for Programmable Instruments) is an ASCII

138keywords. A colon ( : ) separates a command keyword from a lower-level keyword. Command Format Used in This Manual The format used to show comman

139Instead of selecting a specific voltage range, you can substitute MIN to set the range to its minimum value or MAX to set the range t

140IEEE-488.2 Common Commands The IEEE-488.2 standard defines a set of common commands that perform functions like reset, self-test, and sta

15 Figure 1-1 【Step 2】(Pull out the handle) When the handle is turned up to 90° with the multimeter please pull out the handle from the multimeter

141“ON” or “1”. When you query a boolean setting, the instrument will always return “0” or “1”. The following command uses a boo

142C.3 The MEASure? Command MEASure:VOLTage:DC? {<range>|MIN|MAX|DEF},{<resolution>|MIN|MAX|DEF} Preset and make a dc voltage meas

143resolution. The reading is sent to the output buffer. For frequency measurements, the meter uses only one “range” for all inputs between

144measurement. The specified range applies to the source signal and autorange is selected for the reference signal. CONFigure:VOLTage:AC {<r

145CONFigure:PERiod {<range>|MIN|MAX|DEF},{<resolution>|MIN|MAX|DEF} Preset and configure a period measurement with the specified

146[SENSe:]FUNCtion? Query the measurement function and return a quoted string. [SENSe:]<function>:RANGe {<range>|MINimum|MAXimum} Sel

147[SENSe:]TCOuple:TYPE {E|J|K|N|R|S|T} Select thermocouple sensor type. [SENSe:]TCOuple:TYPE? Query thermocouple sensor type. [SENSe:]TCOuple:RJUN

148[SENSe:]TEMPerature:RTD:ALPHa? [MINimum|MAXimum] Query the alpha constant for the user type. [SENSe:]TEMPerature:RTD:BETA {<value>|MINimum|

149Query the A coefficient. [SENSe:]TEMPerature:SPRTD:BX {<value>|MINimum|MAXimum} Set the B coefficient. [SENSe:]TEMPerature:SPRTD:BX? [MINi

150[SENSe:]FREQuency:APERture? [MINimum|MAXimum] Query the gate time (or aperture time) for frequency function. [SENSe:]PERiod:APERture{0.01|0.1|1|M

16 Figure 1-3 【Position 2】 The adjusted position is for operation as shown in Figure 1-4。 Figure 1-4 【Position 3】 The carrying position is wi

151100mV, 1V and 10V ranges. With AUTO OFF, the input resistance is fixed at 10MΩ for all ranges. INPut:IMPedance:AUTO? Query the input resistance m

152 ROUTe:SCAN:COUNT? Read the number of times of scanning. ROUTe:SCAN:COUNT <value> Set the number of times of scanning. ROUTe:SCAN:STATe?

153 CALCulate:PERCent:TARGet? [MINimum|MAXimum] Query the target value for percent math function. CALCulate:AVERage:MINimum? Read the minimum value

154 CALCulate:LIMit:UPPer {<value>|MINimum|MAXimum} Set the upper limit for limit testing. You can set the value to any number from 0 to 120%

155when INITiate is executed. The MEASure? And CONFigure commands automatically select “CALC”. With memory disabled (DATA:FEED RDG_STOR

156Set a trigger delay time in seconds. The delay is the time between the trigger signal and each sample that follows. Specify a delay time

157where you are able to read them into your bus controller. READ? Change the state of the triggering system from the “idle” state to “wa

158 SYSTem:VERSion? Query the present SCPI version. L0 Set to the default identification string. L1 Set to the compatible identification string. S

159SYSTem:ERRor? Query the multimeter’s error queue. Up to 20 errors can be stored in the queue. Errors are retrieved in first-in-first out (FIFO) or

160*OPC Sets the “operation complete” bit (bit 0) in the Standard Event register after the command is executed. *OPC? Returns “1” to the output buff

172.1.2 To connect the power Check the power-line voltage on the rear panel to see if voltage setting is correct for your area. Change the settin

161Many of the required SCPI commands are accepted by the multimeter but are not described in this manual for simplicity or clarity. Most of these no

162LIMit:UPPer {<value>|MINimum|MAXimum} LIMit:UPPer? [MINimum|MAXimum] MXB:MMFactor {<value>|MINimum|MAXimum} MXB:MMFactor? [MINimum|M

163*SRE? *STB? *TRG Dedicated Hardware Lines Addressed Commands ATN IFC REN SRQ Attention Interface Clear Remote Enable Service Request Interrupt D

164configuration states are left unchanged when a device clear message is received. Device clear performs the following actions. All measurements i

165Visual C++ In an MFC application, you can override BERKELEY NUCLEONICS CORPORATION IOUtils interfaces in a class as well as provide additi

166Instance, and Unhandled Exception) is not executed. The Startup Object property can be set in the Application pane of the Project Designer. To ch

167 Rem Open a session to each and determine if it matches stat = viOpen(dfltRM, desc, VI_NULL, VI_NULL, sesn) If (stat < VI_SUCCESS) T

168 Using CONFigure with a Math Operation The following example uses CONFigure with the dBm math operation. The CONFigure command gives you a little

169 If (stat < VI_SUCCESS) Then 'Rem Error finding resources ... exiting MsgBox "1201 device not found.", vbExc

170 MsgBox "System command error.", vbExclamation, "1201 multimeter device test" stat = viClose(fList)

18 Figure 2-1 【Step 2】 Open the voltage setting selector cap as shown in Figure 2-2. (You might need a screwdriver to do so.) Figure 2-2 【Step 3

171 stat = viClose(dfltRM) For i = 0 To (5 - 1) ' print out the 5 times samples reading Debug.Print "Rdgs = "; Mid(re

172 void main(int argc, char* argv[]) { // TODO: Add your control notification handler code here HINSTANCE hUSBTMCLIB;

173 timeout, unsigned long *vi); signed long (__stdcall *PviClose_usb) (unsigned long vi); signed long (__stdcall *PviWrit

174 if (PviOpenDefaultRM_usb == NULL || PviFindRsrc_usb == NULL || PviClose_usb == NULL || PviOpen_us

175 instrDescriptor); if (status < 0L) { // Find the USBTMC device USB[0-9]*::0x164E::0x0FA3::?*INSTR ( Dec ) status =

176 // Write command "*IDN?" and read the 1201 identification string len = 64; pStrout = new char[len]; ZeroMemory(pStrout, len);

177 // Set sample count to 1 strcpy(pStrout, "SAMP:COUN 1"); status = PviWrite_usb(m_instr_usbtmc, (unsigned char *)pStrout, 1

178 printf(" output : READ?\n"); status = PviRead_usb(m_instr_usbtmc, pStrin, 64, &nRead); if (nRead > 0) { for (len=0;

19 Figure 2-3 【Step 4】 Turn it over to 220V position as shown in Figure 2-4. Figure 2-4 【Step 5】 Insert the voltage

202.1.2.2 To change the fuse Warning! Before replacing the power-line fuse, make sure the multimeter is disconnected from the AC po

3Table of Contents 1 GENERAL INFORMATION ... 6 1.1 FEATURE

21【Step 2】 Open the voltage setting selector cap as shown in Figure 2-7. (You might need a screwdriver to do so.) Figure 2-7 【Step 3】 Remove the r

22【Step 4】 Remove the broken fuse from the selector as shown in Figure 2-9. Figure 2-9 【Step 5】 Replace with the new fuse as shown in Figure 2-10.

23【Step 7】 Make sure the power switch on the front panel is in “Power OFF” condition before plugging as shown in Figure 2-12. Figure 2-12 Power sw

24 【Step 9】 Press on the power switch on the front panel for activating 1201 as shown in Figure 2-14. Figure 2-14 Power switch: - “POWER ON”

25AC Digits 5.5 DC digits Slow 5.5 (1 PLC) Voltage Range Auto AC Digits 5.5 DC Digits Slow 5.5 (1 PLC) Current Range Auto Digits 5.5

262.2 Features  Resolution: 6.5 digits.  5*7 dot matrix VFD, dual displays with 3-color annunciators.  11 standard measurement functions &am

27 Figure 2-15 1. Power & Display:  Power: Activates 1201 DMM.  Display: Shows model, version & condition by pressing round

28DIGITS: Changes resolution. RATIO: Enables the dcv:dcv ratio function. %: Calculates the ratio to a target value in percentage. MIN/MAX: C

29measuring. 3-2. The second row in SETUP section: ESC: Cancels selection, moving back to measurement display. ENTER: Accepts selection, movi

30 Figure 2-16 2.3.2 The Display 1201 has a 5x7 dot matrix, dual-display with three-color (White, Red and Yellow) annunciators for a better

4 3.7.2 RTD Measurements ... 45 3.7.2.1 2-Wire RTD Measurements ...

312.3.2.1 Annunciators at Upper Side Figure 2-18 ADRS: Indicates the multimeter is controlled via GPIB Interface. RMT (REMOTE): Indicates t

32 2.3.3 The Rear Panel The rear panel of the 1201 is shown in Figure 2-20. This figure includes important abbreviated information that should be r

33line voltage setting. Configured for line voltages of 100/220V or 120/240V. (Depend on the power utility in your area.) 6. Option Slot:

343 Basic Measurement Function This chapter introduces some basic measurement functions in 1201. You will learn how to use your 1201 multimeter to m

35⑥ Connect test leads to your source signal and observe the reading shown on the display. If the input signal is beyond the allowed range,

36 Figure 3-3 3.2 Current Measurements (DC & AC) The ranges for DC current measurements in 1201 are 10mA, 100mA, 1A and 3A. For AC current m

37 panel or use △ and ▽ buttons to select desired range. ⑥ Connect test leads to your source signal and observe the reading shown on t

383.3 Resistance Measurements (2 & 4-wire) The ranges for resistance measurement are 100 Ω, 1KΩ, 10kΩ, 100kΩ, 1MΩ, 10MΩ, and 100MΩ, with a sen

39 Figure 3-6 Figure 3-7 ※ Note: The rear terminal panel also can be used via the same procedures like the front panel as shown in Fig

40 Figure 3-8 Figure 3-9 3.4 Frequency & Period Measurements 1201 uses an on-board counter with 25MHz to measure the frequency (period). Th

54.4.6 Stepping (Step)...102 4.4.7 Initial Mode...

41③ Set RESOLUTION (Refer to 4.1.1) and INPUT JACK. Or skip this step if default is to be used. ④ Press FREQ button for frequency measuremen

42 value. Figure 3-10 3.6 Diode Measurements 1201 uses a current source of 1 mA for diode testing. The maximum resolution is 10 μV on

43 Figure 3-11 3.7 Temperature Measurements The 1201 supports thermocouples and resistance temperature detector (RTD) types of probes. For thermo

44Sensor Type Temperature Range(°C) Temperature Range(°F) E -270~1000 -518~1832 J -210~1200 -140~2192 S -50~1768 -122~3236 T -270~400 -518~7

45④ Press SHIFT + TEMP buttons. ⑤ Take the reading on the display. Figure 3-12 3.7.2 RTD Measurements There are three kinds of temper

46 Figure 3-13 1245312345

47 Figure 3-14 3.7.2.2 3-Wire RTD Measurements How to measure temperature with 3-Wire RTD The following Figure 3-15 shows theory diag

48 Figure 3-15 12355445123

49 Figure 3-16 3.7.2.3 4-Wire RTD Measurements How to measure temperature with 4-Wire RTD The following Figure 3-17 shows theory diagr

50 Figure 3-17 1235544 12 3

61 General Information This section contains general information about BERKELEY NUCLEONICS CORPORATION 1201 Multimeter. The information is shown bel

51 Figure 3-18 5

524 Front Panel Operations This chapter contains information about how to change the parameters and settings for your measurements and all the detail

53Defaults The default settings for Auto Zero and Auto Gain are enabled. The user selected values for Auto Zero and Auto Gain are stored in

54Fast 5 ½ digits Off Off 0.1 Slow 5 ½ digits On On 1 Fast 6 ½ digits On On 1 Slow 6 ½ digits On On 10 Table 4-1 ※ Note: To change resolut

55 4.1.2 Filter Filter is used to remove noises in measurement readings. 1201 is equipped with two types of filters: AC filter and dig

56Front Panel Operation Press CONFIG + ACV button. Use ◁ and ▷ buttons to locate “BAND WIDTH” submenu, and then press ENTER to select it. Look

57the stack. In the repeating average mode, the multimeter waits for the measurement reading stack to fill up and then take an average to

58 SENSe:AVERage:COUNt {<value>|MINimum|MAXimum} SENSe:AVERage:COUNt? [MINimum|MAXimum] SENSe:AVERage:STATe {OFF|ON} SENSe:AVERage:STATe? 4.1

59Front Panel Operation There are two ways to set the resolution. The locations of the buttons are shown with red rectangle frames in Figure 4-3. A.

60Remote Interface Operation Use the following commands on your PC terminal to set the resolution for your measurement. CONFigure:<function>

7100MΩ. Frequency: From 3Hz to 300kHz. Period measurement. Diode measurement. Continuity measurement for resistance. Thermocouple temperatu

61 Figure 4-4 Remote Interface Operation The automatic input resistance mode can be enabled / disabled. With AUTO OFF (default), the input resistan

62Press CONFIG button and then CONT button. Use ◁ and ▷ buttons to move through the digits and lower or increase the number to your de

63How to set the auto / manual range: You can set the auto / manual range either through the front panel operation or through the remote

64noise rejection and the accuracy of the measurement. The unit of the integration time is in PLC (power line cycles). One PLC for 60 Hz is 16.67 ms,

65 SENSe:FRESistance:DC:NPLCycles {0.02|0.1|1|10|MINimum|MAXimum} SENSe:FRESistance:DC:NPLCycles? [MINimum|MAXimum] For frequency and period measure

66 NTCT 0.003850 0.10863 1.49990 100Ω Table 4-3 Here is the temperature equation that is used to determine the RTD temperature: When Ct 0

67You can set up the RTD configuration either through the front panel operation or through the remote interface operation. Front Panel Op

68Definition If you are using the thermocouple, the options are: type E, J, K, N, R, S and T. After selecting your thermocouple type, you need to con

69 4.1.9 Remote Interface Selection The multimeter supports both GPIB and USB interfaces, but only one interface can be activated at a t

70 “TERMINALS” switch button on the front panel. Please see the following figure for the location of the switch. The location of the butto

8maintenance, unauthorized modification, improper operation, ignorance of environmental specifications or improper software or interfacing

71There are three trigger modes in 1201: auto, immediate, and single triggering. User can specify the trigger mode for their measurement. The factory

72immediate trigger. TRIGger:SOURce IMMediate C. Single Trigger Mode (accessible only through the front panel) Definition Single t

73In 1201, user can specify the trigger source to be one of these three options: front panel operations, external hardware trigger source and remo

74number of samples per trigger, the number of triggers per event, reading hold, and the trigger delay for their measurements. A. Number of samples

75 SAMPle:COUNt <value> B. Number of triggers Although the meter normally takes one trigger before returning to the “idle” state, user can ma

76system is called the “settling time.” The settling time depends on the measurement range, cable properties and signal source. Defaults

77 Table 4-4 How to specify a delay time User can set the delay time from either the front panel operations or the remote interface operations. Fro

78 locate “TRIG” option. Press ENTER to select it. Then again find “DELAY” option using ◁ and ▷ buttons. Press ENTER to select it. Then use ◁ an

79 ※ Note: Press RATIO button, the “RATIO” anunnciator will be lit on the display. 4.3.1 Ratio This function calculates the ratio of an input DC

80 Figure 4-14 Remote Interface Operation Use the following command to make a RATIO measurement. CONFigure:VOLTage:DC:RATio {<range>|MIN|MAX|D

9dangerous situations where damage may result. This product should be placed in a safe area in case of unpredictable personnel use. The rear prot

81and △ and ▽ buttons to increase or decrease the numbers to a desired target value. Press ENTER to set the value. Press % to activate th

82 and will be cleared when the meter is turned off, or when the MIN/MAX is turned on, or after a remote interface reset. The meter beeps every time

83CALCulate:AVERage:MINimum? CALCulate:AVERage:MAXimum? CALCulate:AVERage:AVERage? CALCulate:AVERage:COUNt? 4.3.4 Null Definition When null

84 Figure 4-17 The Remote Interface Operation You can use the following commands on your PC terminal to make a null measurement. CALCulate:FUNCtion

85 limit you wish to set. Then use ◁ and ▷ to move through the digits and △ and ▽ to increase or decrease the numbers to a desired value. Pres

86Figure 4-19 Remote Interface Operation Use the following commands to enable the limits function or to set the limits: CALCulate:FUNCtion LIMit CA

87and B. Press ENTER on your selection. Then use ◁ and ▷ to move through the digits and use △ and ▽ to increase or decrease the number t

88 calculation of dB is listed below: or dB = (Input signal in dBm) – (relative value in dBm) ※ NOTE: The inV is the input signal and the refV is t

89Observe the displayed reading. Figure 4-22 shows the locations of these buttons with red rectangle frames. ※ Note: Press SHIFT+NULL ag

90 reference value. The Zref is adjustable with a range from 50Ω to 8000 Ω. The default value is 600 Ω. The user selected reference value is sto

10Use caution when measuring voltages above 30 V RMS, 42 V peak, or 60 V DC. These voltages pose an electric shock hazard. When using the probe

91resistance is 600 Ω. The locations of the buttons are shown with red rectangle frames in Figure 4-24. ※ Note: Press SHIFT+MIN/MAX

92 allowed for upper row dot-matrix display and a maximum 16 characters are allowed for lower row dot-matrix display as shown on Figure 4-25. User h

93and ▷ buttons. Press ENTER on your selection. The locations of the buttons are shown with red rectangle frames in Figure 4-26. Procedur

94the test voltage is within the limits in diode testing. the source signal fails the limit testing. After the beeper is disabled,

95The following commands show how to use the remote interface operation to disable or enable the beeper: SYSTem:BEEPer SYSTe

96 ※ Note: The MEM annunciator will be lit while the multimeter stores readings and be turned off when the specified number of r

97or retrieve readings in the memory. In addition, the number for STORE function only can be set through front panel. INITiate (This command tel

98 Figure 4-30 4.4.5 Scanning (Scan) User can purchase an optional internal scanner card to be used with 1201 as the following picture shown

99 ※ Note: The output 2 is only for 4-wired resistance measurement. Please refer to the above picture for more connection information. Whe

100DC Signals: 110V DC, 1A switched, 30VA maximum (resistive load). AC Signals: 125V AC rms or 175V AC peak, 100kHz maximum, 1A switched, 62.5VA maxi