Teledyne OT-2 operating instructions Span Gas % F.S. x 4 + = Output in VDC 100

3 Operation Model OT-2 System

NOTE: This procedure is more critical on the 0-10 ppm range and less critical on the 0-100 or 0-1000 ppm range.

3.3.2Setting the Span Pot

1.Switch the system from zero gas to span gas and allow time for stabilization.

Span Pot

Display

Span

Figure 3-6: Span Pot Location

NOTE: The span gas should have an O2 concentration of 80% - 100% of full scale. For example, if the range is set at 0-100 ppm, the span gas should be a certified grade gas of about 90 ppm O2 in N2 or Argon.

2.If 90 ppm gas is used, adjust the span pot (Figure 3-6) to read 90.0 ppm on the LCD display. The output to the Elsag Baily Total Flow TM computer will have a signal of 4.6VDC (into a >10K ohm load).

The formula for this is:

Span Gas % F.S. x 4 + =

1 Output in VDC

100

3-8 Teledyne Analytical Instruments