47
CEM Channel Types
The
Stream-Switched Averaging channel
allows the data logger to monitor one analyzer that
is time-shared between two sampling trains. It forms a base average and two extended averages
from another channel, and accepts data from that input channel only when an on-line digital
input status is met. If this condition is not met, the data can be designated as invalid, or the data
(last good reading, base average, extended average, or average) over the previous on-line period
may be “held” until the on-line status condition is met.When stream switch channels are
controlled by digital event programs or are calibrated using automatic calibration programs,
the digital program or calibration timing may not line up exactlywith the stream switch channels
averaging periods. Calibrations and event programs should be configured to end a few seconds
before the start of the next base average.
On the Misc. tab:
On-Line pattern defines the status input pattern (physical or pseudo-inputs) used to define
when the stream is “on” for data collection purposes.
Offline Action defines how to handle data when the on-line pattern is not active:
• Hold Last (instantaneous) Reading
• Hold Last Base Average
• Invalid (invalidate data)
Purge Time defines how long to continue with the “offline” action when the status inputs
transition from the off-line condition to the on-line condition.
Agilaire 8872 Manual
Chapter 2 Configuration
