ptor, VI_NULL, VI_NULL, &instr) ; The status of the instrument is obtained by reading the status bit. This is done by using the viReadSTB provided by NI-VISA library which has the following parameters (Figure 12.46): ViPUInt16 instrStatus; status = viReadSTB (instr, instrStatus) ; If the status information is only one byte long, the most significant byte is returned with the zero value. Tele-Measurement Services for m-Learning Direction Description Unique logical identifier to a session. status Service request status byte. Figure 12.46 Parameters of viReadSTB() function. 4. "VeLab" Web Service Demo GetInstrumentList operation: the request of this Web service operation has no parameters. SOAP request has the following format: < soapenv : Envelope xmlns:soapenv=http://schemas.xmlsoap.org/soap/envelope/ xmlns:ve ="http://velabservice/"> ksoapenv:Header/> <soapenv:Body> vel:getInstrumentList/> </soapenv:Body :/soapenv:Envelope> This Web service operation returns a list of available instrument resources. The response contains an array of strings representing the resource address in VISA syntax. Example of SOAP response: < SOAP-ENV : Envelope xmlns:SOAP-ENV ="http://schemas.xmlsoap.org/soap/envelope/" xmlns xsd ="http://www.w3.org/2001/XMLSchema" xmlns:xsi = http://www.w3.org/2001/XMLSchema-instance" > SOAP-ENV Body nsl:getInstrumentListResponse xmlns:ns1="http://velabservice/"> hns1:return>visa://192.168.67.101/PxI3::2::INSTR</_return> < nsl:return>visa://192.168.67.101/ASRL1::INSTR</return> isl:return>visa://192.168.67.101/ASRL2::INSTR</return> < insl:return>visa://192.168.67.101/ASRL10::INSTR</_return> ins1:return>visa://192.168.67.101/GPIB0::4::INSTR</return> ns1:return > visa://192.168.67.101/GPIB0::22 </_return> insl:return>pXI5::9::INSTR</return) hns1:return> pXI5::10::INSTR</_return> ns1:return > PXI5: :13: INSTR <</_return> ns1:return > PXI5: :15: INSTR 2</return> nsl:return > PXI4: :6::1: :INSTR</_return> sl:return > ASRL1 : INSTR</_return> </ns1:getInstrumentListResponse> </SOAP-ENV:Body </SOAP-ENV:Envelope: