Teledyne 100AH instruction manual Automatic Zero/Span Check, Dynamic Zero/Span Calibration

Teledyne API Model 100AH SO2 Analyzer Instruction Manual, 02417, Rev. D

8.3 Automatic Zero/Span Check

M100AH can automatically check (AUTOCAL) its calibration each day. If provided with the proper option, the M100AH provides this capability by using the time of day clock to signal the computer system to check operations. When enabled, the instrument software will automatically check zero and span (AUTOCAL) on a timed basis. Optionally, the Z/S cycle can be moved backwards or forwards a fixed time each day (to avoid missing measurements at the same time each day).

Setup of the AUTOCAL is covered in Section 6.3.

8.4 Dynamic Zero/Span Calibration

The AUTOCAL system described above can also optionally be used to calibrate the instrument on a timed basis. The automatic calibration is enabled by setting CALIBRATE button to ON under each SEQUENCE setup (Refer Section 6.3). In addition of AUTOCAL setup, Dynamic Zero and/or Dynamic Span should be enabled. With Dynamic calibration turned on, the instrument will re-set the slope and offset values for the SO2 concentration. To set DYN_ZERO or DYN_SPAN, press SETUP-MORE-VARS-ENTR and press NEXT repeatedly until DYN_ZERO is shown. Press EDIT and toggle OFF (disabled) or ON (enabled).

This continual re-adjustment of calibration parameters can often mask subtle fault conditions in the analyzer. It is recommended that if Dynamic Calibration (especially Dynamic Span) is enabled, the TEST functions, and SLOPE and OFFSET values in the M100AH should be checked frequently to assure high quality and accurate data from the instrument.

8.5 Use of Zero/Span Valves with Remote Contact Closure

The Zero/Span valve option can be operated using Remote Contact Closures provided on the rear panel. See Figure 2-2for connector location and pinout. When the contacts are closed, the analyzer will switch to zero or span mode. The contacts must remain closed for at least 1 second, and the analyzer will remain in zero or span mode as long as the contacts are closed. If either DYN_ZERO or DYN_SPAN is enabled (refer Table 10-5), the calibration is adjusted at the end of the zero or span time, otherwise zero or span is just checked, not adjusted. To set DYN_ZERO or DYN_SPAN, press SETUP-MORE-VARS-ENTR and press NEXT repeatedly until DYN_ZERO is shown. Press EDIT and toggle OFF (disabled) or ON (enabled).

The CPU monitors these contact closures and will switch the analyzer into zero or span mode when the contacts are closed for at least 1 second.

In order to do another remote check, both contact closures should be held open for at least 1 second, then may be set again. Table 8-7shows what type of check is performed based on the settings of the contact closures.

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