Hach 900 Indoor Furnishings User Manual


 
Section 3
Page 17
8544install.fm 12 V dc
Before performing any maintenance, disconnect the sampler from the
power source.
Do not attempt to make any connection or otherwise handle the electrical
components of the sampler when connected to ac line power if the
immediate area is wet, or if hands or clothing are wet.
If the circuit breaker or fuse in the ac power source is tripped, determine
the cause before restoring power to the sampler.
Make sure the power circuit is grounded and protected with a Ground
Fault Interrupter (GFI).
3.9 12 V dc
This connection is for supplying 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 is available
(Cat. No. 1803). This power backup maintains power to the sampler when ac
power fails.
3.10 Auxiliary Connection
The auxiliary interface connector is a general purpose input/output port. Each
signal is described in
Table 2.
Table 1 12 V dc Connector Pin Assignments
Pin Signal Description
A ground
B 12 to 17 V dc unregulated
Table 2 Auxiliary Pin Assignments
Pin Signal Description Wire Color Purpose Rating
A 12 V dc White
This pin can be used to power an external device or flow meter. 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.
C Flow Pulse Input Ye l l o w
With the sampler is in Flow Proportional mode and connected to an
external flow meter, a 5 to 12 V dc input pulse lasting at least 25
milliseconds will cause the sampler to decrement one count. The
sampler is capable of accumulating from 1 to 9999 input pulses.
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 12 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
duration of
at least
25 ms.