Campbell Scientific AVW200 AVW200-series Vibrating Wire Interfaces - Page 45
Programming, 6.1 AVW200 Instruction
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AVW200-series 2-Channel Vibrating Wire Spectrum Analyzer Modules CAUTION When using the "Mcmm" terminal command, no other method of measurement should be used or multiplexing will get out of sequence and measurement errors will result. Read more! Appendix D lists the fields in the public table and provides a brief description of each. Appendix E provides a comprehensive list of status table variables with brief descriptions. 6. Programming 6.1 AVW200 Instruction NOTE If using SDI-12 to communicate with the AVW200, then use the SDI12Recorder instruction to trigger and retrieve measurements from the AVW200 (see Section 6.2, SDI-12 Measurements.) NOTE When using the RS-232 (PakBus) or RF(PakBus) protocol, the datalogger is programmed using the AVW200 instruction in CRBasic. Please ensure that the AVW200 instruction is included in LoggerNet. If using LoggerNet 3.4.1 or lower, the user needs to download the most recent version of the operating system (OS) for the datalogger. This installation installs the required CRBasic files on the user's computer so that the AVW200 instruction shows up in the editor. The AVW200 instruction is used to read measurements from one or more vibrating wire sensors when the sensors are connected to the AVW200 channels directly or connected to a multiplexer that's attached to the AVW200. In addition to frequency, diagnostic information is returned for the sensor (see the Dest parameter). The datalogger program can run the AVW200 instruction in either the pipeline mode (Section 6.1.1, Pipeline Mode) or sequential mode (Section 6.1.2, Sequential Mode). In the pipeline mode, the first execution of the instruction sets up the AVW200; subsequent execution intervals retrieve the data values. If different beginning and ending frequencies are required to measure different types of sensors, use multiple AVW200 instructions with different beginning and ending frequencies specified in each instruction. The sequential mode performs each instruction in sequence; waits for each instruction completion; and then repeats this process for each execution interval. The minimum scan rate for an AVW200 program is 2 seconds per sensor. Syntax AVW200 (Result, ComPort, NeighborAddr, PakBusAddr, Dest, AVWChan, MuxChan, Reps, BeginFreq, EndFreq, ExVolt, Therm50_60Hz, Multiplier, Offset, [Optional] AmpThreshold) Result The Result parameter is a variable that indicates the success or failure of the datalogger's communication attempt with the AVW200. If more than one AVW200 is used and the 37