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KAHN INSTRUMENTS, INC.
885 Wells Road, Wethersfield, CT 06109
Tel: 860-529-8643; Fax: 860-529-1895
E-mail: [email protected]
www.kahn.com
2.6
Operation / Standby Modes
During normal use this switch should be left in the “OPERATE” position.
When in the “STANDBY” mode, the heating and cooling drive to the sensor is disabled.
This allows the sensor mirror to warm / cool to the ambient temperature, and therefore
any dew or contamination that may have formed on the mirror should be removed.
This function is only used for applications where the sample gas dewpoint changes very
quickly from “dry” to “wet”, with the possibility of flooding the sensor’s mirror, or in
circumstances where a manual measurement is only taken very infrequently and it is
prefered to have the sensor disabled between measurements.
When a measurement is to be taken, set the switch to the “OPERATE” position.
2.7
Automatic Balance Compensation (ABC)
During normal use the optical components of the sensor (i.e. mirror, light guides etc.) are
progressively contaminated resulting in a gradual loss of sensitivity. To compensate for
this a balancing system is provided. The system works by heating the sensor mirror to a
temperature sufficiently high to drive off all dew present and provide a dry mirror surface.
This compensates for the presence of any contamination and then the instrument reverts
to the normal measuring mode. This process is fully automated and does not require any
operator intervention. The initialization of this process can either be periodically, at a
preset time interval, or on request.
Selecting the mode of operation for the ABC system is extremely easy. The operator
needs only to configure the period between ABC cycles and the duration of the ABC
cycle required. Both parameters are set by way of banks of DIP switches located on the
rear panel of the instrument. The duration of the balance cycle is user definable from 1 to
8 minutes and should be set using SW4 as shown below:
ABC Duration
SW4-1
SW4-2
SW4-3
SW4-4
1 minute
ON
OFF
OFF
OFF
2 minutes
OFF
ON
OFF
OFF
4 minutes
OFF
OFF
ON
OFF
8 minutes
OFF
OFF
OFF
ON
Notes:
1. Only one switch may be in the ON position at any time.
2. One switch must be in ON position, otherwise, if an ABC is initiated it will
continue indefinitely.
