Campbell Scientific SDM-CD8S 8 Channel Solid State DC Control Module - Manual (Page 21)

SDM-CD8S 8 Channel Solid State DC Control Module
34: Z=F (P30) PUT A "1" INTO FAN
1: 1 F CONTROL LOCATION
2: 0 Exponent of 10
3: 15-- Z Loc :
35: End (P95)
End fan loop
36: End (P95)
End then do
37: If time is (P92)
1: 0 minutes into a Reset flag 2 at the
2: 15 minute interval end of the 15 minute
3: 22 Set low Flag 2
END FAN CONTROL LOGIC BASED ON TIME
INPUT LOCATIONS 10 THROUGH 24 ARE NOW LOADED WITH "1" OR "0" TO SET
PORTS ON THE SDM-CD8S.
38: SDM-CD16 (P104)
Send instructions to the
1: 1 Reps SDM-CD8S with address 00
2: 00 Address
3: 11 Loc
39: End Table 1 (P)
8.3 Control Gas Sampling Based on Time – CR1000
The SDM-CD8S is ideal for controlling low power DC operated solenoid
valves such as might be used to control a manifold as part of a gas sampling
system. This example shows one way to do that.
8.3.1 Terminology
Site: A site may be the physical site where the air is sampled (i.e. intake or
chamber) or a connection to a calibration gas. Each site has a unique
SDMCD8S/valve setting that configures the manifold to connect gas from that
site to the sample path of the gas analyzer. There are 8 connections to the “site
selection” manifold. The numbers 1 through 8 identify the sites. The site
numbers are the same as the number of the intake on the manifold and the
number of the SDMCD8S relay controlling that valve. Sites 1 – 6 are
connected to sample intakes to measure a atmospheric profile and sites 7 and 8
are used for calibration gases.
Site Sequence: The sequence in which the sites are measured is determined
by the SiteSequence array. The sites are measured in the sequence that the site
numbers are entered in this array, not necessarily in order of site number.
The SiteSequence array also allows a site to be measured multiple times within
the sequence. For some measurements it is necessary to measure calibration
gases frequently (e.g., the concentration of various isotopes of CO
2
with a trace
gas analyzer.)
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