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1、 Remote Control Manual Remote Control Manual LeCroy 9300 .; Upper or lower-case characters or both can be used in program messages. The instrument does not decode incoming program messages before receiving a terminator. The exception to this is when the program message is longer than the 256 byte in
2、put buffer: the oscilloscope will start analyzing the message when the buffer is full. Commands and queries are executed in the order in which they are transmitted. In GPIB mode, the following are valid terminators: New-line character (i.e. the ASCII new- line character, whose decimal value is 10).
3、New-line character with a simultaneous signal. signaltogetherwiththelast character of the program message. 14ISSUED: September 2001LCXXX-RM-E Rev P About Remote ControlAbout Remote ControlAbout Remote ControlAbout Remote Control The terminatorisalwaysusedinresponse messages sent by the instrument to
4、 the controller. In RS-232-C, the terminator may be defined by the user with the command “COMM_RS232”. The default value is , i.e. the ASCII carriage return character, the decimal value of which is 13. ExamplesExamplesExamplesExamplesGRID DUAL This program message consists of a single command that i
5、nstructs the instrument to display a dual grid. The terminator is not shown, as it is usually automatically added by the interface driver routine writing to the GPIB (or RS-232). DZOM ON; DISPLAY OFF; DATE? This program message consists of two commands, followed by a query. They instruct the instrum
6、ent to turn on the multi-zoom mode, turn off the display, and then ask for the current date. Again, the terminator is not shown. Command/Query FormCommand/Query FormCommand/Query FormCommand/Query FormThe general form of a command or a query consists of a command header optionally followed by one or
7、 several parameters separated by commas: ? ,., The notation ? shows that the question mark is optional (turning the command into a query). The detailed listing of all commands in System Commands indicates which may also be queries. There is a space between the header and the first parameter. There a
8、re commas between parameters. ExampleExampleExampleExampleDATE 15,JAN,1993,13,21,16 This command instructs the oscilloscope to set its date and time to 15 JAN 1993, 13:21:16. The command header “DATE” indicates the action, the 6 data values specify it in detail. HeaderHeaderHeaderHeaderThe header is
9、 the mnemonic form of the operation to be performed by the oscilloscope. All command mnemonics are listed in alphabetic order in the System Commands section. The majority of the command/query headers have a long form for optimum legibility and a short form for better transfer and decoding speed. The
10、 two forms are fully equivalent and can be 9300 C2:OFST? What is the vertical sensitivity and the offset of channel 2? C2:VDIV?; OFST?Sameasabove,without repeating the path. DataDataDataDataWhenever a command/query uses additional data values, the values are expressed in terms of ASCII characters. T
11、here is a singleexception:thetransferofwaveformswiththe command/query “WAVEFORM”, where the waveform may be expressed as a sequence of binary data values. Chapter 4 gives a detailed explanation of waveform format. ASCII data can have the form of character, numeric, string or block data. Character da
12、taCharacter dataCharacter dataCharacter dataThese are simple words or abbreviations for the indication of a specific action. ExampleExampleExampleExampleDUAL_ZOOM ON Here, the data value “ON” commands that the dual-zoom mode be turned on (the data value “OFF” in such a case will obviously have the o
13、pposite effect). However, this can become more complex. In some commands, where as many as a dozen different parameters are able to be specified, or where not all the parameters are applicable at the same time, the format requires pairs of data values. The first value names the parameter to be modif
14、ied, while the second gives its value. Only those parameter pairs changed need indicating: ExampleExampleExampleExampleHARDCOPY_SETUP DEV,EPSON,PORT,GPIB Here, two pairs of parameters are specified. The first specifies the device as the EPSON printer (or compatible) and the second indicatestheGPIBpo
15、rt.Whilethecommand “HARDCOPY_SETUP” allows many more parameters, they are either not relevant for printers or are left unchanged. Numeric DataNumeric DataNumeric DataNumeric DataThe numeric data type is used to enter quantitative information. Numberscanbeenteredasintegersorfractions,orin exponential
16、 representation: 9300 TRIG_MODE NORM;C1:COUPLING? (terminator not shown). The instrument might respond as follows: TIME_DIV 50 NS;C1:COUPLING D50 (terminator not shown). Theresponsemessagerefersonlytothequeries: “TRIG_MODE” is left out. If this response is sent back to the instrument, it is a valid
17、program message for setting its timebase to 50 ns/div and the input coupling of Channel 1 to 50 W. Whenever a response is expected from the instrument, the control program must instruct the GPIB or RS-232-C interface to read from the instrument. If the controller sends another program message withou
18、t reading the response to the previous one, the response message in the output buffer of the instrument is discarded. The instrument uses somewhat stricter rules for response messages than for the acceptance of program messages. Whereas the controller may send program messages in upper or lower case
19、 characters, response messages are always returned 9300 IBERR% 210END 250PRINT “READ ERROR =”;IBERR% 260END The GPIB status word ISTA%, the GPIB error variable IBERR% and the count variable IBCNT% are defined by the GPIB handler and are updated with every GPIB function call. Refer to the National In
20、struments manual for details. The sample program above would report if the GPIB address of the instrument was set to a value other then 4. Line 180 resets the instrument to local with a call to the GPIB routine IBLOC. Additional Driver CallsAdditional Driver CallsAdditional Driver CallsAdditional Dr
21、iver CallsIBLOC is used to execute the IEEE 488.1 standard message Go To Local (GTL), i.e. it returns the instrument to the local state. The programming example above illustrates its use. IBCLR executes the IEEE 488.1 standard message Selected Device Clear (SDC). IBRDF and IBWRTF, respectively, allo
22、w data to be read from GPIB to a file, and written from a file to GPIB. Transferring data directly to or from a storage device does not limit the size of the data block, but may be slower than transferring to the computer memory. IBRDI and IBWRTI, respectively, allow data to be read from GPIB to an
23、integer array, and written from integer array to GPIB. Since the integer array allows storage of up to 64 kilobytes (in BASIC), IBRDI and IBWRTI should be used for the transfer of large data blocks to the computer memory, rather than IBRD or 210ISSUED: September 2001LCXXX-RM-E Rev P GPIBGPIBGPIBGPIB
24、 IBWRT, which are limited to 256 bytes by the BASIC string length. Note that IBRDI and IBWRTI only exist for BASIC, since for more modern programming languages, such as C, the function calls IBRD and IBWRT are far less limited in terms of data-block size. IBTMO can be used to change the timeout valu
25、e during program execution. The default value of the GPIB driver is 10 seconds for example, if the instrument does not respond to an IBRD call, IBRD will return with an error after the specified time. IBTRG executes the IEEE 488.1 standard message Group Execute Trigger (GET), which causes the oscill
26、oscope to arm the trigger system. National Instruments supply a number of additional function calls. In particular, it is possible to use the so-called board level calls which allow a very detailed control of the GPIB. Service RequestsService RequestsService RequestsService RequestsWhen an oscillosc
27、ope is used in a remote application, events often occur asynchronously at times that are unpredictable for the host computer. The most common example of this is the wait of a trigger after the arming of the instrument: the controller must wait until the acquisition is finished before it can read the
28、 acquired waveform. The simplest way of checking if a certain event has occurred is by either continuously or periodically reading the status bit associated with it until the required transition is detected. Continuous status bit polling is described in more detail below. For a complete explanation
29、of status bytes refer to Chapter 5. A potentially more efficient way of detecting events occurring in the instrument is the use of the Service Request (SRQ). This GPIB interrupt line can be used to interrupt program execution in the controller. The controller can then execute other programs while wa
30、iting for the instrument. Unfortunately, not all interface manufacturers support the programming of interrupt service routines. In particular, National Instruments supports only the SRQ bit within the ISTA% status word. This requires the user to continuously or periodically check this word, either e
31、xplicitly or with the function call IBWAIT. In the absence of real interrupt service routines the use of SRQ may not be very advantageous. 9300 *SRE 1” Note:Note:Note:Note: The SRQ bit is latched until the controller reads the STatus Byte Register (STB). The action of reading the STB with the comman
32、d “*STB?” clears the register contents except the MAV bit (bit 4) until a new event occurs. Service requesting may be disabled by clearing the SRE register (“*SRE 0”). Note on Terms:Note on Terms:Note on Terms:Note on Terms: The term “soft-key”, used here in reference to remote operations, is synony
33、mous with “menu button”, used exclusively in the accompanying Operators Manual for front-panel operations. Both terms refer to the column of seven buttons running parallel to the screen on the oscilloscope front panel and the functions they control. 212ISSUED: September 2001LCXXX-RM-E Rev P GPIBGPIB
34、GPIBGPIB CALL IBWRT(SCOPE%,CMD$) Example 2Example 2Example 2Example 2 To assert SRQ when soft key 4 (fourth menu button from top of screen) is pressed. The event “soft key 4 pressed” is tracked by the URR register. Since the URR register is not directly reflected in STB but only in the ESR register
35、(URR, bit position 6), the ESE enable register must be set first with the command “*ESE 64” to allow the URQ setting to be reported in STB. An SRQ request will now be generated provided that the ESB summary bit (bit position 5) in the SRE enable register is set (“*SRE 32”): CMD$=“*ESE 64;*SRE 32” CA
36、LL IBWRT(SCOPE%,CMD$) 9300 INE 1; *SRE 1” CALL IBWRT(SCOPE%,CMD$) MASK% = *PRE 1” CALL IBWRT(BRD0%,CMD$) CMD4$=CHR$( INE 1; *PRE 1” CALL IBWRT(SCOPE%,CMD$) LOOP% = 1 WHILE LOOP% CMD$=“*IST?” CALL IBWRT(SCOPE%,CMD$) CALL IBRD(SCOPE%,RD$) IF VAL(RD$) = 1 THEN LOOP% = 0 WEND 9300 *STB? 9300 WAVEFORM? a
37、nd putting the response directly into a disk file. 46ISSUED: September 2001LCXXX-RM-E Rev P Waveform StructureWaveform StructureWaveform StructureWaveform Structure WAVEFORM?, Related Commands, and BlocksWAVEFORM?, Related Commands, and BlocksWAVEFORM?, Related Commands, and BlocksWAVEFORM?, Related
38、 Commands, and Blocks Using the WAVEFORM? query is an effective way to transfer waveform data using the block formats defined in the IEEE- 488.2 standard. Responses can then be downloaded back into the instrument using the WAVEFORM command. All of a waveforms logical blocks can be read with the sing
39、le query: C1:WAVEFORM? This is the preferred form for most applications due to its completeness. Time and space are the advantageswhen reading many waveforms with the same acquisition conditions, or when the interest is only in large amounts of raw integer data. And any single block can be chosen fo
40、r reading with a query such as: C1:WAVEFORM? DAT1 The description In the System Commands section provides the various block names. Interpreting theInterpreting theInterpreting theInterpreting the Waveform DescriptorWaveform DescriptorWaveform DescriptorWaveform Descriptor The binaryresponse to a que
41、ryof the form: C1:WAVEFORM? or C1:WAVEFORM? ALL can be placed in a disk file and then dumped to show the following hexadecimal and ASCII form: Done using the GPIB bus with default settings. Note:Note:Note:Note: A waveform query response can easily be a block containing over 16 million bytes if it is
42、 in binary format and twice as much if the HEX option is used. 9300 WAIT;C1:WF?to wait for the event, transfer the data,andthenstartanew acquisition. This line can be “looped” in the program as soon as it has finished reading the waveform. LCXXX-RM-E Rev PISSUED: September 200151 5 5 5 5 Status Regi
43、stersStatus RegistersStatus RegistersStatus Registers Using Status RegistersUsing Status RegistersUsing Status RegistersUsing Status Registers A wide range of status registers allows the oscilloscopes internal processing status to be determined quickly at any time. These registers and the instrument
44、s status reporting systemaredesignedtocomplywithIEEE488.2 recommendations.Followinganoverview,startingthis page, each of the registers and their roles are described. Related functions are grouped together in common status registers. Some, such as the Status Byte Register (STB) or the Standard Event
45、Status Register (ESR), are required by the IEEE 488.2 Standard. Other registers are device-specific, and include theCommandErrorRegister(CMR)andExecutionError Register (EXR). Those commands associated with IEEE 488.2 mandatory status registers are preceded by an asterisk . OverviewOverviewOverviewOv
46、erviewThe Standard Event Status Bit (ESB) and the Internal Status Change Bit (INB) in the Status Byte Register are summary bits of the Standard Event Status Register (ESR) and the Internal State Change Register (INR). The Message Available Bit (MAV) is set whenever there are data bytes in the output
47、 queue. The Value Adapted Bit (VAB) indicates that a parameter value was adapted during a previous command interpretation (for example, if the command “TDIV 2.5 US” is received, the timebase is set to 2 m s/div along with the VAB bit). The Master Summary Status bit (MSS) indicates a request for serv
48、ice from the instrument. The MSS bit can only be set if one or more of the other bits of STB are enabled with the Service Request Enable Register (SRE). All Enable registers (SRE, ESE and INE) are used to generate a bit-wise AND with their associated status registers. The logical OR of this operatio
49、n is reported to the STB register. At power-on, all Enable registers are zero, inhibiting any reporting to the STB. The Standard Event Status Register (ESR) primarily summarizes errors, whereas the Internal State Change Register (INR) reports internal changes to the instrument. Additional details of errors reported by ESR can be obtained with the queries “CMR?”, “DDR?”, “EXR?” and “URR?”. 52ISSUED: September 2001LCXXX-RM-E Rev P Status RegistersStatus RegistersStatus RegistersStatus Registers Status Register Structure 0 0 0 1 1 11 2 2 2 3 3 33 4 4 4151211109 5 5
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