21555_REVF_MAN 电路图.pdf

Giga-tronics Incorporated v 4650 Norris Canyon Road v San Ramon, California 94583 925.328.4650 or 800.726.4442 v 925.328.4700 (Fax) v 800.444.2878 (Customer Service) v 925.328.4702 (CS Fax) ISO 9001. Certified Process Registrar: BSI, Certification No. FM 34226 v Registered 04 June 1996 v Amended 01 March 2000 P/N: Revision: Publication Date: 58542 VXIbus Universal Power Meter Operation address 255 permits the Resource Manager to dynamically address the unit based on the chassis VXI slot. To change the logical address, set the respective sections on the eight position DIP switch. The switch is accessible after removing the right cover (see Figure 2-1). The address is set with binary values of 0 to 255. Switch position 1 is the least significant bit of the address. Figure 2-1 illustrates logical address values of 3 (binary 00000011) and 255 (binary 11111111). Giga-tronics ships the power meter with a logical address of 255 for dynamic configuration. Figure 2-1: Setting the Logical Address RIGHT SIDE HOUSING COVER 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 LOGICAL ADDRESS:LOGICAL ADDRESS: 2553 8-POSITION DIP SWITCH Operation Publication 21555, Rev. F, March 20072-3 2.3.2Data Transfer Bus Arbitration The power meter has VMEbus Mastership capability. When enabled, it sends responses and events as signals (software interrupts) to its Commander Signal Register. The power meter cannot drive the interrupt lines. The power meter is configured as a level 3 requester by the factory. The level 3 Bus Request and Bus Grant lines (BR3*, BG3IN* and BG3OUT*) are used. The other Bus Grant lines are daisy-chained by jumpers (see Figure 2-2). The VMEbus specifications describe three priority schemes: (1) Prioritized, (2) round-robin, and (3) single level. Prioritized arbitration assigns the bus according to a fixed priority scheme where each of four bus lines has a priority from highest (BR3*) to lowest (BR0*). Round-robin arbitration assigns the bus on a rotating basis. Single level arbitration accepts requests only on BR3*. The jumpers must be changed if a different requester level is required. Figure 2-2 will aid in reconfiguring the power meter to a new level. Refer to the VMEbus specification for more information on data transfer bus arbitration. Figure 2-2: Default Bus Arbitration Settings 13 1213 1213 1213 12 24 124 124 124 1 BR0 BG0IN BG0OUT BR1 BG1IN BG1OUT BR2 BG2IN BG2OUT BR3 BG3IN BG3OUT 0 123 FACTORY SETTING ARBITRATION LEVEL BUS REQUEST ARBITRATION LEVEL JUMPER BLOCK RIGHT SIDE HOUSING COVER 58542 VXIbus Universal Power Meter 2-4Publication 21555, Rev. F, March 2007 2.4Sensor Precautions Sensors used with the 58542 are configured in metal housings for superior mechanical performance as well as excellent shielding. When connecting the sensors to other devices or components, the body of the sensor should never be turned to tighten the RF connection. Mechanical damage to the connector can result if im- properly handled when connecting the sensors. Scratched or damaged connector mating surfaces can lead to inaccurate mea- surements. If a sensor is connected to CW or peak power devices with power output in excess of +23 dBm (200 mW), degradation or destruc- tion of the diode can occur. Diodes degraded or destroyed in this manner will not be replaced under warranty. Destructive signal levels are higher for High Power, TrueRMS, and Low VSWR sensors. 2.5Operation 2.5.1SCPI Command Interface This section details operation of the power meter using the SCPI interface commands. A SCPI Command Reference is presented in Table 2-2 and the sections that follow. The power meter is compatible with the Standard Commands for Programmable Instruments (SCPI) standard. SCPI promotes consistency in its definition of a common instrument control and measurement command language. The structured approach of the SCPI standard offers test system design engineers a number of system integration advantages that achieve considerable efficiency gains during control program development. SCPI compatible instrument commands are structured from a common functional organization or model of a test instrument (see Figure 2-3). Most of the power meter configuration and measurement functions fall within the Measurement Function Block and the Trigger Subsystem of the SCPI instrument model. The 58542 uses the SENSe Subsystem of the Measurement Function Block to implement commands that apply specifically to the individual power sensors; sensor 1, and sensor 2. For example, the SENSe2:CORRection:OFFSet command corrects for the attenuation of a signal that passes through an attenuator or coupler before it is measured by power sensor 2. Figure 2-3 illustrates the SCPI subsystem model. NOTE: Throughout this manual, some commands will be in both upper and lowercase, such as CALCulate and MEMory. The uppercase is the required input. The whole word can be used if desired. CAUTION * Operation Publication 21555, Rev. F, March 20072-5 Figure 2-3: SCPI Subsystem Model SENSeCALCulate TRIGgerMEMory 58542 VXIbus Universal Power Meter 2-6Publication 21555, Rev. F, March 2007 2.5.2Sensor and Channel Configuration The CALCulate Subsystem of the Measurement Function Block contains commands that define the form of the measured data from sensor 1 and sensor 2. CALCulate commands define the configuration of the two Software Calculation Channels (channels). For example, the CALC1:POW 1 command configures channel 1 to report the power level as measured by sensor 1. CALC2: RAT 2,1 configures channel 2 to report the ratio of power levels, sensor 2 over sensor 1. 2.5.3Measurement TRIGgering The power meter uses the TRIGger Subsystem to trigger measurements in two different operational modes - a normal mode which maximizes the instruments functionality, and swift and burst modes that maximize the power measurement rate. 2.5.4MEMory Functions The MEMory commands control the configuration of the automated Voltage-Proportional-to-Frequency (VPROPF), sensor Cal Factor correction, and the Analog Output on the front panel. Each of these connectors is used with external devices. The VPROPF can be configured to match the VPROPF output of your microwave source. The Analog Output is used with a variety of devices including chart recorders, oscilloscopes, voltmeters, and microwave source leveling inputs. 2.5.5IEEE 488.2 Commands Consistent with SCPI compliance criteria, the power meter implements all the common commands declared mandatory by IEEE 488.2. These commands are listed in Table 2-1. 2.5.6DIAGnostic Commands DIAGnostic commands are used for a variety of instrument specific maintenance and calibration functions. Unless you are performing instrument calibration functions, it is unlikely that you will need to use the DIAGnostic command sets. For calibration laboratory metrology professionals, the DIAG commands will allow you to completely automate instrument and sensor calibration functions. The commands program EEPROMs inside the meter and individual sensors. If desired, a password function Table 2-1: VXI GPIB Command Syntax MnemonicName *CLSClear Status Command *ESEStandard Event Status Enable Command *ESE?Standard Event Status Enable Query *ESR?Standard Event Status Register Query *IDN?Identification Query *OPCOperation Complete Command *OPC?Operation Complete Query *RSTReset Command *SREService Request Enable Command *SRE?Service Request Enable Query *STB?Read Status Byte Query *TST?Self-Test Query *WAIWait-to-Continue Command Operation Publication 21555, Rev. F, March 20072-7 is incorporated to prevent unauthorized personnel from altering calibration information. Table 5-1 in Chapter 5 lists available Diagnostic commands. 2.5.7CALCulate Subsystem Commands CALCulate: commands specify and query the configuration of power measurement channels, known in SCPI references as Software Configuration Channels, and in this manual as “channels.” (For sensor specific configuration and measurement function control, see Section 2.5.8). The query form of CALC#? with the appropriate modifier (1 or 2) inserted ahead of the ? will return the current configuration status for that channel. This can be used to verify configuration commands or return current status information following data acquisition or power measurements. Limit Lines are set on a channel basis. The LIMit commands set limits, monitor the number of violations, and allow the violation counter to be cleared. The REFerence command allows channel based offset values. For example, using CALC#:REF:COLL automatically converts the inverse of the current channel measurement value to an offset - simplifying the 1 dB compression testing of amplifiers. MIN and MAX commands monitor deviation of measured values over a user controllable time period. The two software calculation channels can individually and simultaneously perform the internal instrument functions that calculate final measurement data for output over the VXI bus to the controller. The final measurement data is calculated from SENSe Subsystem processed sensor data as well as the CALC subsystem channel configuration data. Figure 2-4: CALculate Subsystem Command Tree Channel Configuration CALCulate POWer RATio STATe DIFFerence UNIT :CHAN:FUNC? LIMit UPPer LOWer FAIL? FCO? CLEar STATe REFerence STATe COLLect MAXimum STATe MINimum STATe 58542 VXIbus Universal Power Meter 2-8Publication 21555, Rev. F, March 2007 This means that only two measurement configurations can be obtained from the 58542 simultaneously. For example, the controller can obtain measurements for sensor 1 plus sensor 2/sensor 1 simultaneously, but not sensor 1 plus sensor 2 plus sensor 2/sensor 1 simultaneously. 2.5.8SENSe Subsystem Commands The SENSe subsystem configuration commands, illustrated in Figure 2-5, apply specifically to individual sensors. These commands alter the value of the measured power level according to the sensors characteristics. For example, measured power levels can be offset for attenuators or couplers in the measurement path so that the power data reading reflects the power level at the measurement point of interest. Use SENSe for: Averaging power measurements in the 58542 rather than the controller Offsetting power measurements for attenuation or amplification Entering the operating frequency of the measured signal (automatically computes and applies sensor specific Calibration Factor corrections) which compensates for sensor frequency response characteristics Controlling Peak Power Sensor triggering SENSe subsystem commands control functions that are related directly to the individual power sensors. For example, these commands control items that would not apply to numerical alteration of a ratio measurement of Sensor1/Sensor2. Controls that would apply to that type of a configuration are channel functions, not sensor functions, and would therefore be located in the CALCulate subsystem. Figure 2-5: SENSe Subsystem Command Tree SENSe AVERage COUNt TCONtrol STATe OFFSet FREQuency VPROpf EEPROM TYPE? FREQuency CALFactor TOTAl? OFFSet SOURce LEVel DELay TRIGgerCORRection STATe COLLect For Peak Power Sensors Only Operation Publication 21555, Rev. F, March 20072-9 SENSe:AVERage functions control the number of data samples for each measurement and the manner in which those numbers are accumulated. COUNt determines the averaging number or AUTO-averaging. TCONtrol determines whether each new sample is added to previous COUNt # of samples or if COUNt # of samples are taken each time the 58542 instrument is triggered. Please note that the SENSe:TRIGger commands are not instrument triggers, but Peak Power Sensor configuration controls. SENSe:TRIGger functions apply only to Giga-tronics Peak Power Sensors. The DELay and LEVel functions of these Peak Power Sensor controls apply to the 80350A Peak Power Sensors, not the 80340 Peak Power (Triggerable Pulse) Sensors. The AVERage and CORRection commands apply to all 80300 Series CW Instrument Measurement Event Triggering, and Special Triggering Configuration commands for the fast reading buffered data modes, Burst Mode and Swift Mode. The TRIGger command tree is illustrated in Figure 2-6. The query form of these commands, TRIGger? with the appropriate modifier inserted ahead of the ?, will return the instruments current configuration status. This can be used to verify triggering configuration or return status information following command errors which are commonly caused by using illegal configuration commands during SWIFt or BURSt Modes. SOURce:IMMediate triggering allows the 58542 to control measurement triggering; this is the default configuration. EXTernal triggering is performed using a TTL signal into the front panel connector. There is provision for connecting this trigger signal to the backplane TTL Triggering, but the ASCII software command syntax remains EXT. BUS allows software controlled triggering. COUNt refers to the number of data points to store in the meters 5000 reading buffer (128,000 with option 02) before the measurement data is requested by the controller. DELay controls the time interval between Burst Mode data samples, and the MODE command controls whether the data is taken after Figure 2-6: TRIGger Subsystem Command Tree General Instrument Measurement Triggering Burst or Swift Mode Data Acquisition Controls TRIGger COUNt DELay MODESOURce HOLD IMMediate EXTernal BUS 58542 VXIbus Universal Power Meter 2-10Publication 21555, Rev. F, March 2007 receipt of the instrument trigger or if data is collected (in a FIFO buffer) immediately preceding receipt of an instrument trigger. 2.5.10GPIB Command Syntax The following conventions are used with the GPIB commands in this manual. Throughout this manual, some commands will be in both upper- and lowercase, such as CALCulate and MEMory. The uppercase is the required input. The whole word can be used if desired. Table 2-2 lists in alphabetical order all of the VXI GPIB commands supported by the power meter. A typical example is shown, the basic function performed by that command is given, and the page numbers of this chapter where descriptions of each command can be located. 2.5.10.1Commands in Brackets Commands and command separators within brackets, such as COMMand:, are optional. These portions of the commands may be used in your program command strings, but are not required for proper operation of the power meter. 2.5.10.2Programmer Selectable Parameters Command descriptions enclosed in angle brackets () show the syntax placement of configurable or settable parameters. A description of the necessary parameter and the range of values or mnemonics which are valid for that parameter are located enclosed in angle brackets. 2.5.10.3Italics in Syntax Descriptions Some command syntax descriptions show certain words in italics such as space and comma to indicate where the character must be included within a command string. 2.5.10.4Query Format ? Exce