Measurement Specialties 9116 user manual Delivery of Acquired Data To Host

Models: 9116

1 143
Download 143 pages 39.58 Kb
Page 35
Image 35

Pressure Systems, Inc.

Model 9116 User’s Manual

 

 

The Configure/Control Multi-Point Calibration (‘C’) command, actually 4 sub-commands, is an improvement over the single calibration commands (‘h’ and ‘Z’) described above. Though ‘C’ provides for the adjustment of the same offset and gain correction coefficients already described above, it does so with two or more applied pressure calibration points. The final linear fit (i.e., new offset and gain correction coefficients) is a “least squares” correction fit between all the calibration points specified. This ‘C’ command is particularly useful in calibrating differential transducers over their entire negative-to-positive range.

Although the calculated offset and gain correction coefficients are kept in volatile memory following execution of the calibration commands, they may be stored in non-volatile transducer memory following the execution of the calibration commands (for use by all subsequent EU conversions). This is accomplished with the Set/Do Operating Options (‘w’) command (Index 08 and 09).

The above correction coefficients are maintained internally in IEEE floating-point format. The Read Internal Coefficients (‘u’) command and the Download Internal Coefficients (‘v’) command can return (or manually set) calibration coefficients to the host in decimal or hex dump formats in their responses.

3.1.4.4Delivery of Acquired Data To Host

Several commands apply to host delivery of acquired data, either on demand or autonomously. The Read High Precision Data (‘r’) command may be used to obtain high precision data (selected channels in various formats). The modules also provide several high speed, high resolution output commands. The Read High-Speed Data (‘b’) command is used to read “pure binary” engineering unit pressure (all channels in the lowest overhead format). Use the ‘r’ and ‘b’ commands to get acquired data on demand.

The module can also deliver EU pressure data in streams, which consist of TCP/IP or UDP/IP data packets that arrive autonomously in the host (with data from selected channels being delivered in various formats at various rates). Up to three independent streams may be configured, started, stopped, and cleared with the Define/Control Autonomous Host Streams (‘c’) command. In conjunction with hardware triggering, this autonomous delivery method can also make the module acquire (as well as deliver) data in its most efficient and time- synchronized manner. This also frees the host to receive, process, or record these data in its most efficient manner, since it need not waste time continually requesting new data with commands.

The modules also have special purpose on demand data acquisition commands, including: Read Transducer Voltages (‘V’) and Read Transducer Raw A/D Counts (‘a’), which provide two views of raw pressure data. It has similar commands providing EU temperature (￿C) and other raw views of each channel’s special temperature signal, including Read Transducer Temperatures (‘t’), Read Temperature A/D Counts (‘m’), and Read Temperature Voltages (‘n’). This command group is generally used for diagnostic purposes. All of these special purpose data (plus other module status information) may also be periodically delivered to the host automatically in any of the three flexible autonomous streams configured by the ‘c’ command.

Page 26

www.PressureSystems.com

Page 35
Image 35
Measurement Specialties 9116 user manual Delivery of Acquired Data To Host