Hach SIGMA 900, User Manual

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8837ext.fm
Connecting to External Devices
Section 3 Connecting to External Devices
The Sigma 900 All Weather Refrigerated Sampler can connect to several
different external devices. This chapter describes the characteristics of
each interface connector signal on the sampler and pin assignments.
Section 5 contains information on programming the sampler to connect to
external devices.
3.1 Using the 12 V dc Connection
The 12 V dc connection supplies power to the sampler controller electronics.
Power is normally supplied to the sampler controller electronics from either a
battery or a power supply located in the pocket directly behind the sampler
controller housing.
In the event of a power outage, an optional 12 V dc battery backup
(Cat. No. 8801) is available. The battery backup maintains power to the
sampler when ac power fails.
3.2 Using the Auxiliary Connection
Pin Signal Description
A Ground
B 12 to 17 V dc, unregulated
A
B
C
D
E
F
Pin Signal Description
Wire
Color
Description Rating
A 12 V dc White
Powers an external device or flow meter. Power is supplied form another
source such as a battery. Must be used in conjunction with Pin B (ground). 13.8 V dc
nominal
B ground Blue
Connected to dc ground and is isolated from the earth ground found in the
ac power line. 13.8 V dc
nominal
C Pulse Input Yellow
With the sampler in Flow Proportional mode and connected to an external
flow meter, a 5 to 17 V dc input pulse lasting at least 25 milliseconds will
cause the sampler to decrement one count. The 12 V dc line found on Pin
A can be used directly with a simple contact closure to Pin C or an external
5 to 17 V dc pulse may be applied providing the ground side of the
external signal is connected to the sampler ground at Pin B. This count is
actuated at the beginning of the input signal (the leading edge of the
pulse).
5 to 17 V
dc pulse
with a
duration
of at least
25 ms.