Campbell Scientific AP200 CO2/H2O Atmospheric Profile System - Manual (Page 65)

AP200 CO
2
/H
2
O Atmospheric Profile System
Assume there are eight profile levels and that the AP200 is configured to set
the zero and span every four hours.
From Appendix F, Valve Sequence Timing, the zero/span sequence will select
the CO
2
span cylinder for 40 s, the zero cylinder for 100 s, and then the CO
2
span cylinder again for 70 s. The total sequence time for the CO
2
span cylinder
will be 110 s (as, 40 s + 70 s = 110 s) and 100 s for the zero cylinder.
Assuming a flow of 250 ml/min, each zero/span cycle will consume:
250 ml/min * 110 s * (1 min/60 s) * (1 L/1000 ml) = 0.46 L for the
CO
2
span tank, and
250 ml/min * 100 s * (1 min/60 s) * (1 L/1000 ml) = 0.42 L for the
zero tank
Rounding this volume up to 0.5 L, and assuming the cylinders hold 200 cf (5.7
m 3 ), each cylinder will last:
5.7 m 3 * (1000 L/m 3 )/0.5 L = 11,400 zero/span cycles
At a 4-hr interval, this is 1,900 days, or more than five years.
8. Repair
The AP200 is designed to give years of trouble-free service with reasonable
care. However, if factory repair is needed, first contact a Campbell Scientific
applications engineer to obtain an RMA (Return Materials Authorization)
number. An RMA number and product-safety documents are required prior to
any repair shipments being accepted at Campbell Scientific.
Consult with a Campbell Scientific applications engineer to determine which
parts or assemblies should be sent for repair. Do not attempt to disassemble
the system without specific instructions from Campbell Scientific. Exceptions
are the IRGA and the NL115/CFM100, which are easy to remove and install.
If the system enclosure is to be returned, plug the inlets and cap the ends of all
tubes to keep debris out. Swagelok ® caps and plugs have been provided for
this purpose.
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