Remote Zero/Span Check (Contact Closure) - Teledyne 401 Instruction Manual

Teledyne API Model 401 O
3. Allow to sample zero gas for approximately 10 minutes.
4. Follow sequence of SETUP, BCAL, and ZERO. Then select "yes" to adjust zero.
NOTE: in case of using external dry zero air, check if dry zero air is supplied into the rear
panel port (see Figure 1-5 for pneumatic connections) at about 30 - 40 PSI pressure. O
generator flow should be exceeding at least 1 l/min in addition of total flow demands. (See
Section 1.6.5 for O3 generator flow adjustment.)
Photometer Span Calibration
1. Turn the power on for both Model M401 and Model M400 (master standard). Let them
stabilize for minimum of one hour.
2. Start to generate the span (O
password (512). (In case of using external dry zero air, verify proper pressure of external air
source.)
3. Allow to sample span gas for approximately 10 minutes.
4. Follow the sequence of SETUP, BCAL, and enter correct span concentration related to the
Model M400 (master standard). Then select "yes" to set span.

3.7 Remote Zero/Span Check (Contact Closure)

In addition to calibration check via the front panel buttons, the calibrator can be activated by
means of two contact closures called EXT-ZERO-CAL and EXT-SPAN-CAL. (See Figure 1-2
for the location of the terminals for connection of the contacts on the rear panel.) The CPU
monitors these two contact closures every 1 second and looks for a positive transition (i.e. 0 ->
1) on either signal. If a positive transition occurs on EXT-ZERO-CAL, the M401 will perform a
zero check. If a positive transition occurs on EXT-SPAN-CAL, the M401 will perform a span
check. If a positive transition occurs on both EXT-ZERO-CAL and EXT-SPAN-CAL
simultaneously and ASEQ is preset, then the M401 will perform a multi-point sequence as
selected in SETUP-EVNT-ASEQ menu (see Section 4.2.). When a negative transition (i.e. 1 ->
0) is detected, the CPU will go into standby mode.
Also, if a positive transition occurs on either signal while the M401 is in zero, span check or
ASEQ mode, it will immediately switch to the specified mode. For example, if the analyzer is in
zero check and a positive transition is detected on EXT_SPAN_CAL, then the instrument will
immediately go into span check. To perform a zero check followed by a span check, first
generate a positive transition on EXT-ZERO-CAL, and then when you want to do the span
check, generate a positive transition on EXT-SPAN-CAL.
The remote calibration signals may be activated in any sequence, providing a virtually unlimited
number of calibration types.
Photometric Calibrator Instruction Manual, 01124, Rev. J1
3
) gas by pressing O
3
3-4
GN from the main menu and enter the
3
3