Access from the user program

The index registers R38 and R39 can be used to specify which process data are cyclically transferred from the oscilloscope terminal

to the controller. Maximum values, minimum values, RMS values, mean values, individual sampling values (sample n after trigger event), rise times, pulse widths etc. can thus optionally be represented directly in the process data.

The index register R37 can be used to specify which process data are cyclically transferred to oscilloscope terminal

. Switching thresholds, pulse widths etc. can thus optionally be specified via the process data channel.

Evaluation of a recording

A recording is requested via the bEnableTrigger bit. Current values are present in the memory if the bTriggerDone bit appears in the status byte of the terminal. If the memory is to be read or evaluated, the bEnableTrigger bit must remain set, otherwise the memory is continuously overwritten.

Evaluation of the memory is activated via the bEvalBuffer bit. Current values are present in the process data, as soon as the bEvalBufferDone bit appears. Multiple evaluation of the memory is thus possible. Mean value, maximum value, minimum value, RMS value of the recording can thus be read sequentially.

Reading the trace memory

Samples can be read via the Trace data registers R60 and R61. To this end, the offset within the memory can be specified via the Trace index register (R62).

The Zoom register (R63) can be used to specify a number nS of samples for which the maximum value, minimum value and mean value is calculated, or the sample interval nS at which the values are output. After each read access of R60 or R61, the Trace index register (R62) is incremented by nS.

For calling up all values from the memory, enter the value 0x0000 in R62 and 0x0001 in R63. Then read R60 and R61 alternatively. If only every second value is to be read, enter the value 0x0002 in R63.

Envelope monitoring

Each recording can be monitored with a tight or a wide interval. The tight interval is subsequently referred to as inner envelope curve, the wide interval as outer envelope curve.

Application sample:

  • Monitoring of an ageing process via the inner envelope curve
  • Monitoring of malfunctions via the outer envelope curve

A reference curve can be placed in the flash memory of the terminal, which is copied to the RAM after a terminal reset.

If evaluation of the inner or outer error counter is activated, i.e. if the index register for process data (R38 or R39) contains the value 18 or 19, the difference between the respective actual value and the target value is compared with parameter x of the envelope curve (R53, R54). If the difference is greater, the respective counter is incremented.

The RAM area can be overwritten with current trace data (Teach-in) via the command register (R7) using the instruction WriteEnvCurvToRAM (0x0201), or it can be directly written and read from offset 0x8000. The command WriteEnvCurvToFLASH (0x0202) can then be used to place data in the flash memory, and are retained even if the voltage supply fails.