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Table 2–1
pH Amp range settings
corresponding to pH
ranges
22
Signal Display
The signal at a channel's input is displayed so that you can see the
effect of changing the settings – no data are recorded at this time.
Slowly drifting signals are shown quite accurately, whereas quickly
changing signals are displayed as a solid dark area showing only the
envelope (shape) of the signal from minimum and maximum values.
The average signal value is displayed at the top of the display area.
You can stop the signal scrolling by clicking the Pause button at the
bottom left (Macintosh) or top right (Windows) of the data display
area. This changes to the Scroll button on the Macintosh. Click the
Scroll button to start scrolling again.
Shift and stretch the vertical Amplitude axis, by clicking and dragging
it in various ways, to make the best use of the available display area.
It functions the same as the Amplitude axis of the Chart Window,
controls are identical and any change is applied to the Chart Window.
Setting the Range
The
Range
pop-up menu lets you select the input range or sensitivity
of the channel – the combined range of the pH Amp and PowerLab.
Changing the range in the pH Amp dialog is the equivalent to
changing it in the Chart or Scope window; applied once you click
At 25 °C a range of 59 mV corresponds to a range of approximately
one pH unit. This relationship is the basis for Table 2–1, which shows
the pH ranges corresponding to pH Amp range settings. For general
pH measurements, a range of 500 mV should be used, while the
200 mV range is suited for biological pH monitoring.
Range setting (mV)
±500
15.6
±200
6.25
±100
3.13
±50
1.56
±20
0.625
†
Resolution is 16 bits, or 0.0015%, of range setting with LabChart and Scope software.
* This range will be limited by the pH electrode
†
Resolution
(μV)
Range (pH)
–1.5 to 15.5*
3.6 to 10.4
5.3 to 8.7
6.2 to 7.8
6.7 to 7.3
Resolution (pH)
< 0.001
< 0.001
< 0.001
< 0.001
< 0.001
pH Amp Owner's Guide
.
OK
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