Teledyne API Model 200AH NO
X
Analyzer Instruction Manual, 06492, Rev. G2
6-2
6.2. Zero/Span Valves Option
The Zero/Span Valve option consists of a manifold of stainless steel valves plus drive electronics
connected to the CPU. The Option consists of two variations. Option 50 has 2 - 2-way valves,
1 3-way valve and operates in 3 modes:
1. Sample mode, all 3 valves off, sample gas flows through the sample port to the instrument.
2. Zero mode, sample-cal valve is energized to shut off sample flow, zero valve is energized to
input zero gas.
3. Span mode, sample-cal valve is energized to shut off sample flow, span valve is energized to
input low concentration range span gas.
Option 52 consists of all of the features in Option 50 plus a second span valve to allow a low and
high concentration of span gas.
See
Figure 2-6 for valve location. Fittings on the rear panel are for two concentrations of span gas
plus zero gas. (See Figure 2-2 and Figure 2-4) The valves are can be operated by several
methods shown in Table 6-1.
Note: The Zero/Span Valves option cannot be included in an instrument that also includes an Oxygen
Sensor.
Table 6-1: Zero/Span Valve Operation
Mode Description Reference Section
1. Front panel operation via
CALS and CALZ buttons
Calibration Section 7 - Manual Zero/Span Check
2. Automatic operation using
AUTOCAL
Setup and use of AUTOCAL is described in Table 6-2 and
Section 7.2
3. Remote operation using the
RS-232 interface
Setup described in Section 6.2 Operation of AUTOCAL
described in Section 7.2
4. Remote operation using
external contact closures
Section 7.5 - Automatic operation using external contact
closures. Table 7-12 and Section 9.3.4.3
Zero and span gas inlets should supply their respective gases in excess of the demand of the
Analyzer. Supply and vent lines should be of sufficient length and diameter to prevent back
diffusion and pressure effects. See Figure 2-4 for fitting location and tubing recommendations.
Note that Zero/Span Valves cannot be included in an instrument that also includes the Oxygen
sensor option.
