Copper Mountain Technologies ACM8000T and ACM6000T. SCPI Programming Manual Revision 1

Transcription

1 Copper Mountain Technologies ACM8000T and ACM6000T Revision

2 C O N T E N T S 1 Introduction Document Scope Reference Computer control PC Interface Software Examples Introduction to SCPI Command Tree Subsystems Optional subsystems Full and abbreviated format Case insensitivity Parameters Numerical parameters Character parameters Query commands Required commands and system status IEEE Commands Notation Syntax Mandatory IEEE488.2 parameters group... 8 *CLS... 8 *ESE... 8 *ESR?... 9 *IDN?... 9 *OPC *OPC? *RST *SRE *STB? ACM Command Group MEAS:TEMP? PATH:COUN? PATH:STAT MEM:TABL:DATA? MEM:TABL:POIN? MEM:TABL:DATE? MEM:TABL:TIME? MEM:TABL:FREQ:STAR? MEM:TABL:FREQ:STOP? MEM:TABL:TEMP? MEM:TABL:CONN? MEM:TABL:ADAP? MEM:TABL:ANAL? MEM:TABL:PLAC? MEM:TABL:OPER? MEM:TABL:THER:MAGN? MEM:TABL:THER:PHAS? MEM:TABL:THER:POIN? MEM:TABL:THER:FREQ:STAR?

3 MEM:TABL:THER:FREQ:STOP? SYST:ERR? Appendix 1. IEE488.2 Status Reporting System Appendix 2. Error Codes Appendix 3. Programming Examples

4 1 Introduction 1.1 Document Scope This manual contains descriptions of the SCPI (Standard Commands for Programmable Instruments) command set for Copper Mountain Technologies automatic calibration module (ACM) series, designed to manage the module through its USB interface. 1.2 Reference IEEE Standard , IEEE Standard Codes, Formats, Protocols and Common Commands for Use with ANSI / IEEE Std IEEE, New York, NY, SCPI Standard-1999, Standard Commands for Programmable Instruments Volume 1: Syntax and Style. SCPI Consortium, San Diego, CA, (USBTMC-USB488) Universal Serial Bus Test and Measurement Class, Subclass USB488 Specification. 2 Computer control 2.1 PC Interface The ACM module is controlled from a personal computer equipped with a standard USB interface. 2.2 Software To communicate with the device, a VISA library must first be installed on the PC. The Universal Library VISA in turn enables control of instrumentation from virtually any programming language, including C/C++, Visual Basic, MATLAB, LabView and others. The VISA library supports a variety of interfaces and protocols, including the protocol USBTMC-USB488, which is utilized for interfacing with the ACM. There are various implementations of the VISA library. Any of the VISA library implementations can be used, notably National Instruments (NI-VISA), or Agilent IO Libraries Suite. 2.3 Examples Appendix 3 of this manual contains example programs. Source code examples in C are contained in the folder Examples\USB488\C. 4

5 3 Introduction to SCPI The control protocol implemented in the ACM is based on standard USBTMC- USB488, which is based in turn on an earlier standard for control and communication with instrumentation: IEEE These standards specify the program-level command language used as SCPI-1999, Standard Commands for Programmable Instruments. SCPI commands are intended for sending symbolic messages between the host computer and the measuring device. SCPI is maintained by the SCPI Consortium ( The basic details of the standard SCPI are described below. More information about the SCPI standard can be downloaded from the SCPI Consortium website. 3.1 Command Tree SCPI Commands are organized in a tree structure, for example: :MEASure :MEMory :TEMPerature :TABLe :DATA Each tree structure forms a functional system. The beginning of each functional system is called the root, such as "MEASure" and "MEMory". Each functional system may have a lower-level subsystem. End nodes are called leaves. The complete sequence of all nodes, from root to leaf--plus the worksheet--forms the command tree. 3.2 Subsystems The colon character ( : ) separates each subsystem. Additionally, this symbol denotes a lower subsystem. The first colon in the command can be omitted, for example: MEASure:TEMPerature 3.3 Optional subsystems Some subsystems can be declared optional, if their omission does not result in ambiguity. Optional subsystems may be omitted when sending a command. Optional subsystems are enclosed in square brackets ( [ ] ). For example, if the full specification of the command is: [SOURce:]PATH:STATe the subsystem "SOURce" is optional. So both formulations are correct: SOURce:PATH:STATe and 5

6 PATH:STATe 3.4 Full and abbreviated format Each keyword in the specification of the instruction has a full and abbreviated format. The abbreviated format is denoted in uppercase. For example, the full command: MEASure:TEMPerature Can be abbreviated as: MEAS:TEMP Only the full or abbreviated form of a keyword is valid, for example, the following command is invalid: MEAS:TEMPer 3.5 Case insensitivity Commands are case insensitive. Uppercase and lowercase letters in the commands specification are used only to denote differences between the full and abbreviated commands. For example the following commands are equivalent: MEAS:TEMP meas:temp 3.6 Parameters Commands can have parameters. Parameters are separated by space. If the command has several options, they must be separated by a comma (, ). The ACM uses only two kinds of parameters: numeric and character Numerical parameters Numerical parameters are integers or real numbers. For example: *ESE Character parameters The SCPI standard allows for using input character data as parameters. For example, consider the following command: [SOURce:]PATH:STATe {A B AB},{SHORt OPEN LOAD THRU} 6

7 The first parameter takes the value A, B or AB, and the possible values of the second parameter are SHORt, OPEN, LOAD" or THRU. Symbolic parameters can be specified in a full or abbreviated format, subject to the same rules mentioned above (see Section 3.4). 3.7 Query commands Query commands are used to read parameter values from the instrument. After sending a query command, it is expected that data will be sent in the opposite direction via USB. Query commands have a question mark (? ) at the end of the command. Many commands have two types. The type without the question mark writes a parameter, and the type with the question mark reads it. For example: PATH:STATe A,SHORT PATH:STATe? A 3.8 Required commands and system status IEEE488.2 SCPI-compliant devices must support a certain set of commands and system status, specified in the standard IEEE Mandatory commands begin with an asterisk ('*'). Mandatory commands include the following: *CLS *ESE *ESE? *ESR? *IDN? *OPC *OPC? *RST *SRE *SRE? *STB? The scheme for reading system status (Status Reporting System) is provided in Appendix 1. Required commands and system status are supported by the ACM to ensure compatibility with the SCPI standards and with IEEEE

8 4 Commands 4.1 Notation This section describes the notational conventions used in the remainder of the document Syntax Symbolic expression syntax legend: < > Identifiers enclosed in < > indicate that the data should be provided to a particular type [ ] Identifiers inside square brackets [ ] may be omitted { } Identifiers enclosed by { } are designated selections. Individual elements are separated by Space The space character is used to separate commands, The comma indicates a separator between parameters Three dots indicate missing mandatory parameters 4.2 Mandatory IEEE488.2 parameters group *CLS *CLS Clears the following (no request): Error Queue Status Byte Register Standard Event Status Register *ESE *ESE <numeric> 8

9 *ESE? Sets or reads the Standard Event Status Enable Register (command/request). Parameter <numeric> from 0 to 255 Out of range Побитовое AND с числом 255 <numeric> Default value 0 *ESR? *ESR? Reads the Standard Event Status Register. Execution of the command clears the value of the register (query only) <numeric> *IDN? *IDN? Reads a string identifying the device. Format string: <manufacturer> <model> <serial number "," number of software / hardware version> (query only). Example: Planar, ACM8000T, , 1.0/01 String up to 40 characters 9

10 *OPC *OPC Sets the OPC bit (bit 0) in the Standard Event Status Register to complete all transactions (not requested). Group implemented only for compatibility, since there are no asynchronous operations in the automatic calibration module. *OPC? *OPC? Reads 1 upon completion of all operations (query only). Group implemented only for compatibility, since there are no asynchronous operations in the automatic calibration module. 1 *RST *RST Sets the module in the initial state (no request). The initial status of the requested port calibration module is LOAD. 10

11 *SRE *SRE <numeric> *SRE? Sets or reads the Service Request Enable Register (command/request) Parameter <numeric> from 0 to 255. Out of range Bitwise AND with the number 255 <numeric> Default value 0 *STB? *STB? Reads the Status Byte Register (query only). <numeric> 11

12 4.3 ACM Command Group MEAS:TEMP? MEASure:TEMPerature? Reads the temperature inside the enclosure calibration module (inquiry only) in units of C. Units С (degrees Celsius) <numeric> PATH:COUN? [SOURce:]PATH:COUNt? {A B AB} Reads the number of unique states for each port or between the two ports of the calibration module (query only) Parameter A B AB : Port A : Port B : Thru between Ports А and В Invalid Parameter An error occurs and the command is ignored. <numeric> 12

13 PATH:STAT [SOURce:]PATH:STATe {A B AB},{SHORt OPEN LOAD THRU ATTenuator LOAD2 OPEN2} [SOURce:]PATH:STATe? {A B AB} Sets or reads the state of each port or state between the two ports of the calibration module (command / request) A B AB : Port A : Port B : Between Ports А and В Parameters SHORt OPEN LOAD THRU ATTenuator OPEN2 LOAD2 : Short state of reflection : Open state of reflection : Load state of reflection : Thru state with lowest possible attenuation : Thru state with high attenuation : Second open state* : Second load state* Invalid Parameter An error occurs and the command is ignored. Furthermore, the parameters SHORt OPEN LOAD OPEN2 LOAD2 can be specified only in conjunction with Parameter A or B, and Parameters THRU ATTenuator can be specified only in conjunction with Parameter AB, otherwise an error occurs and the command is ignored. {SHOR OPEN LOAD THRU ATT LOAD2 OPEN2 NONE} Note NONE is read when the query pair is invalid, for example when a query is made for AB and one of the states of reflection * ACM8000T only 13

14 MEM:TABL:DATA? MEMory:TABLe:DATA? {A B AB},{SHORt OPEN LOAD T11 T21 T12 T22 A11 A21 A12 A22 LOAD2 OPEN2}[,{FACTory USER1 USER2 USER3}] Reads calibration characterization data from the module memory (inquiry only). The arrays contain S-parameters of the ACM for each of the module states. For states of reflection (SHORt, OPEN, LOAD, LOAD2, OPEN2) the memory array contains S11 for each port. For states of transmission ((THRU, ATT) the memory array contains four S parameters: S11, S21, S12, and S22. Each command call returns the array for one S-parameter according to the specified parameters. All S-parameter arrays are presented in the format of log amplitude (db) and phase (degrees). The array size is 2N, where N is the number of points on the frequency axis. For the n-th point, where n is from 1 to N: <numeric 2n 1> <numeric 2n> logarithmic amplitude S-parameter, in db; phase S-parameter, in degrees. A B AB : Port A of the module : Port B of the module : Path between Ports A and B of the module Parameters SHORt OPEN LOAD T11 T21 T12 T22 A11 A21 A12 A22 OPEN2 LOAD2 : Array containing S11 data of SHORt : Array containing S11 data of OPEN : Array containing S11 data of LOAD : Array containing S11 data of THRU : Array containing S21 data of THRU : Array containing S12 data of THRU : Array containing S22 data of THRU : Array containing S11 data of ATTenuator : Array containing S21 data of ATTenuator : Array containing S12 data of ATTenuator : Array containing S22 data of ATTenuator : Array containing S11 data of OPEN2* : Array containing S11 data of LOAD2* FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 14

15 Invalid Parameter An error occurs and the command is ignored. In addition, the parameters SHORt OPEN LOAD LOAD2 OPEN2 may only be specified in conjunction with A or B, and the parameters T11 T21 T12 T22 A11 A21 A12 A22 may only be specified in conjunction with AB, otherwise an error occurs and the command is ignored <numeric 1>, <numeric 2>, <numeric 2N> * ACM8000T only MEM:TABL:POIN? MEMory:TABLe:POINts? {[FACTory] USER1 USER2 USER3} Reads the number of points in the characterization table of the ACM (inquiry only). A value of zero means that there is no characterization. Factory characterization never reads a zero value, since it can not be omitted. Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <numeric> 15

16 MEM:TABL:DATE? MEMory:TABLe:DATE? {[FACTory] USER1 USER2 USER3} Returns date of ACM characterization (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <numeric 1>, <numeric 2>, <numeric 3> where: <numeric 1> year from 1900 to2999; <numeric 2> month from 1 to12; <numeric 3> day from 1 to31. 16

17 MEM:TABL:TIME? MEMory:TABLe:TIME? {[FACTory] USER1 USER2 USER3} Returns time of ACM characterization (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <numeric 1>, <numeric 2>, <numeric 3> where: <numeric 1> mour from 0 to23; <numeric 2> minute from 0 to59; <numeric 3> second from 0 to59. MEM:TABL:FREQ:STAR? MEMory:TABLe:FREQuency:STARt? {[FACTory] USER1 USER2 USER3} Reads the start frequency of the ACM characterization data (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. Units Hz (Hertz) <numeric> 17

18 MEM:TABL:FREQ:STOP? MEMory:TABLe:FREQuency:STOP? {[FACTory] USER1 USER2 USER3 } Reads the stop frequency of the ACM characterization data (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. Units Hz (Hertz) <numeric> MEM:TABL:TEMP? MEMory:TABLe:TEMPerature? {[FACTory] USER1 USER2 USER3} Reads the temperature of the ACM characterization data (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. Units С (degrees Celsius) <numeric> 18

19 MEM:TABL:CONN? MEMory:TABLe:CONNector? {A B},{[FACTory] USER1 USER2 USER3} Reads the connector type of the ACM (inquiry only). A B : ACM Port A : ACM Port B Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <string> MEM:TABL:ADAP? MEMory:TABLe:ADAPter? {A B}, {[FACTory] USER1 USER2 USER3} Reads the type of adapters if adaptors were used to characterize the module (inquiry only). A B : порт A калибровочного модуля : порт B калибровочного модуля Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <string> 19

20 MEM:TABL:ANAL? MEMory:TABLe:ANALyzer? {[FACTory] USER1 USER2 USER3} Reads the type of analyzer which was used to characterize calibration module (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <string> MEM:TABL:PLAC? MEMory:TABLe:PLACe? {[FACTory] USER1 USER2 USER3} Reads the location of calibration of the module (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <string> 20

21 MEM:TABL:OPER? MEMory:TABLe:OPERator? {[FACTory] USER1 USER2 USER3} Reads the name of the operator who performed the ACM characterization (inquiry only). Parameter FACTory : Factory data (default) USER1 : User data 1 USER2 : User data 2 USER3 : User data 3 Invalid Parameter An error occurs and the command is ignored. <string> 21

22 MEM:TABL:THER:MAGN? MEMory:TABLe:THERmocompensation:MAGNitude? {A B AB},{SHORt OPEN LOAD T21 T12 T11 T22 A21 A12 A11 A22 LOAD2 OPEN2} Reads the the coefficient of magnitude temperature compensation (km) for the transmission or reflection parameter corresponding to the specified state of the ACM (inquiry only). Temperature compensation is used to improve the calibration accuracy by compensating for changes in the parameters of the ACM resulting from changes in its internal temperature. Magnitude coefficients of compensation are applied to the magnitude data read by the command MEM:TABL:DATA?. Mc = M km ΔT, Mc compensated magnitude (db), M uncompensated magnitude (db), km magnitude temperature compensation coefficient(db/ C), ΔT temperature change ( C). ΔT = T char T, T char temperature of characterization (MEM:TABL:TEMP?), T current internal temperature of the module (MEAS:TEMP?) Temperature compensation can be applied to both the factory characterization data and to user data characterizations. The array size of the temperature compensation coefficients is N, where N is the number of points on the frequency axis (MEM:TABL:THER:POIN?). The points are spaced linearly between the start and stop frequencies (MEM:TABL:THER:FREQ:STAR?, MEM:TABL:THER:FREQ:STOP?). The size of the temperature compensation coefficients array may not match the size of the user characterization array. Furthermore, the user characterization may be performed at other frequencies. In such cases it is possible to use linear interpolation to determine the coefficients of thermal compensation of frequency points other than the frequencies at which they are specified. For n-th point, where n is from 1 to N: <numeric n> magnitude temperature compensation coefficient of the reflection or transmission of the specified single state of the calibration module (db/ C). 22

23 A B AB : Port A of the module : Port B of the module : Between Ports A and B of the module Parameters SHORt : Short state of reflection OPEN : Open state of reflection LOAD : Load state of reflection T21 : S21 of Thru transmission state T12 : S12 of Thru transmission state T11 : S11 of Thru transmission state T22 : S22 of Thru transmission state A21 : S21 of Attenuator transmission state A12 : S12 of Attenuator transmission state A11 : S11 of Attenuator transmission state A22 : S22 of Attenuator transmission state OPEN2 : Second open state of reflection * LOAD2 : Second load state of reflection * Invalid Parameter An error occurs and the command is ignored. In addition, the parameters SHORt OPEN LOAD LOAD2 OPEN2 may only be specified in conjunction with A or B, and the parameters T11 T21 T12 T22 A11 A21 A12 A22 may only be specified in conjunction with AB, otherwise an error occurs and the command is ignored <numeric 1>, <numeric 2>, <numeric N> Related Commands MEM:TABL:THER:POIN? MEM:TABL:THER:FREQ:STAR? MEM:TABL:THER:FREQ:STOP? MEM:TABL:DATA? MEM:TABL:TEMP? MEAS:TEMP? * ACM8000T only 23

24 MEM:TABL:THER:PHAS? MEMory:TABLe:THERmocompensation:PHASe? {A B AB},{SHORt OPEN LOAD T21 T12 T11 T22 A21 A12 A11 A22 OPEN2 LOAD2} Reads the phase coefficient of temperature compensation (kp) for the transmission or reflection parameter corresponding to the specified state of the ACM (inquiry only). Temperature compensation is used to improve the calibration accuracy by compensating for changes in the parameters of the ACM resulting from changes in its internal temperature. Phase coefficients of compensation are applied to the phase data read by the command MEM:TABL:DATA?. Pc = P kp ΔT, Pc compensated phase(deg), P uncompensated amplitude (deg), kp phase temperature compensation coefficient (deg/ C), ΔT temperature change ( C). ΔT = T char T, T char temperature of characterization (MEM:TABL:TEMP?), T current internal temperature of the module (MEAS:TEMP?) Temperature compensation can be applied to both the factory characterization data and to user data characterizations. The array size of the temperature compensation coefficients is N, where N is the number of points on the frequency axis (MEM:TABL:THER:POIN?). The points are spaced linearly between the start and stop frequencies (MEM:TABL:THER:FREQ:STAR?, MEM:TABL:THER:FREQ:STOP?). The size of the temperature compensation coefficients array may not match the size of the user characterization array. Furthermore, the user characterization may be performed at other frequencies. In such cases it is possible to use linear interpolation to determine the coefficients of thermal compensation of frequency points other than the frequencies at which they are specified. For n-th point, where n is from 1 to N: <numeric n> phase temperature compensation coefficient of the reflection or transmission of the specified single state of the calibration module (deg/ C). 24

25 A B AB : Port A of the module : Port B of the module : Between Ports A and B of the module Parameters SHORt : Short state of reflection OPEN : Open state of reflection LOAD : Load state of reflection T21 : S21 of Thru transmission state T12 : S12 of Thru transmission state T11 : S11 of Thru transmission state T22 : S22 of Thru transmission state A21 : S21 of Attenuator transmission state A12 : S12 of Attenuator transmission state A11 : S11 of Attenuator transmission state A22 : S22 of Attenuator transmission state OPEN2 : Second open state of reflection * LOAD2 : Second load state of reflection * Invalid Parameter An error occurs and the command is ignored. In addition, the parameters SHORt OPEN LOAD LOAD2 OPEN2 may only be specified in conjunction with A or B, and the parameters T11 T21 T12 T22 A11 A21 A12 A22 may only be specified in conjunction with AB, otherwise an error occurs and the command is ignored. <numeric 1>, <numeric 2>, <numeric N> Related Commands MEM:TABL:THER:POIN? MEM:TABL:THER:FREQ:STAR? MEM:TABL:THER:FREQ:STOP? MEM:TABL:DATA? MEM:TABL:TEMP? MEAS:TEMP? * ACM8000T only 25

26 MEM:TABL:THER:POIN? MEMory:TABLe:THERmocompensation:POINts? Reads the number of points in the table of coefficients of temperature compensation (query only). A value of zero means that there is no temperature compensation data. <numeric> Related Commands MEM:TABL:THER:MAGN? MEM:TABL:THER:PHAS? MEM:TABL:THER:FREQ:STAR? MEMory:TABLe:THERmocompensation:FREQuency:STARt? Reads the start frequency of the table of temperature compensation coefficients (inquiry only). Units Hz (Hertz) <numeric> Related Commands MEM:TABL:THER:MAGN? MEM:TABL:THER:PHAS? 26

27 MEM:TABL:THER:FREQ:STOP? MEMory:TABLe:THERmocompensation:FREQuency:STOP? Reads the stop frequency of the table of temperature compensation coefficients (inquiry only). Units Hz (Hertz) <numeric> Related Commands MEM:TABL:THER:MAGN? MEM:TABL:THER:PHAS? SYST:ERR? SYSTem:ERRor[:NEXT]? Reads runtime SCPI command errors from the FIFO (first in first out) error queue, which is stored in the device. The read message is removed from the queue. The *CLS command clears the error queue. The maximum size of the queue is 16 posts (inquiry only). <numeric>, <string> where: <numeric> error code <string> message text If the queue contains no messages: "0, No error" 27

28 Appendix 1. IEE488.2 Status Reporting System... Service Request Enable Register *SRE SRQ Service Request Generation RQS ESB MAV EAV MSS Status Byte Register *STB? Command Error Execution Error Device spec. Error Query Error Standard Event Status Enable Register *ESE Standard Event Status Register *ESR? Output Queue Error/ Event Queue 28

29 Appendix 2. Error Codes 1 "Characterization data not found" 2 "Thermocompensation data not found or corrupted" 3 "Data array corrupted or not found" 4 "Too many requests in line" 5 "Internal device error" -102 "Syntax error" -110 "Invalid command header" -211 "Trigger ignored" -220 "Parameter error or invalid parameter" 29

30 Appendix 3. Programming Examples Example 1. Programming in C. The following program demonstrates automation of the instrument in C using the VISA library. The device is connected using USB. When the program is run from the command line, the device address is passed using the VISA resource name format. For more information about the VISA resource name, please consult the VISA library documentation. Program description: 1. Establish a connection to the device; 2. Retrieve and print the device identification string; 3. Switch and port status read (PrintPortsState( )); 4. Reading of the temperature inside the module; 5. Retrieval of the module characterization data; 6. Printing of the data to the screen. // Example1.cpp // // VISA Header: visa.h (must be included) // VISA Library: visa32.lib (must be linked with) #include <visa.h> #include <stdio.h> #include <stdlib.h> #include <string.h> // // Send request and read device respond bool Query(ViSession instr, char * cmd, ViByte *response, ViUInt32 buffersize ) { ViUInt32 readcnt, writecnt; int c = strlen((char*)cmd); if( VI_SUCCESS == viwrite(instr, (ViByte *)cmd, c, &writecnt)) { if( VI_SUCCESS == viread(instr, response, buffersize, &readcnt)) { // Replace the last symbol '\n' by '\0' response[readcnt-1] = '\0'; return true; } } return false; } //

31 // Print ports state void PrintPortsState(ViSession instr) { ViByte response[255]; } Query(instr, "SOUR:PATH:STAT? A\n", response, 255); printf("port A state: %s\n", response); Query(instr, "SOUR:PATH:STAT? B\n", response, 255); printf("port B state: %s\n", response); Query(instr, "SOUR:PATH:STAT? AB\n", response, 255); printf("port AB state: %s\n", response); // int main (int argc, char * argv[]) { const int buffersize = 16384; ViStatus status; ViSession defaultrm, instr; // Error checking // Communication channels // Buffer for string I/O ViByte * buffer = (ViByte*)malloc(sizeof(ViByte) * buffersize); char * dev; // VISA resource name printf("example 1\n\n"); if(buffer == NULL) { printf("out of memory."); return -1; } if( argc!= 2) { printf("usage:\n Example1.exe <visa resource name>"); return -1; } else dev = argv[1]; // Start Visa session if((status = viopendefaultrm(&defaultrm))!= VI_SUCCESS) { printf("can't initialize VISA\n"); return -1; } // Open Device if((status=viopen(defaultrm,dev,vi_null,vi_null,&instr)!= VI_SUCCESS)) { printf("can't open VISA address: %s\n", dev); return -1; } // Get IDN string Query(instr, "*IDN?\n", buffer, buffersize); printf("\nget IDN String:\n%s\n", buffer); 31

32 // Switch port state viprintf(instr, "PATH:STATE A,OPEN\n"); printf("\nports states:\n"); PrintPortsState(instr); // Print ports states // Get device temperature Query(instr, "MEAS:TEMP?\n", buffer, buffersize); printf("\ndevice temperature:\n%s\n", buffer); // Get characterization data array printf("\nget data array (Port:A, State:Short, Data:Factory)\n"); Query(instr, "MEM:TABL:DATA? A,SHOR\n", buffer, buffersize); printf("%s", buffer); } return 0; 32