User Manual

Global Water Instrumentation
7
Digital Control Outputs
There are up t o two control outputs available that can be used to remotely control
pumps, valves, lights, etc. These ar e open-c ollec tor outputs that source current to
ground with a maximum of 100mA per c hannel. Driving larger loads requires a relay
or some other type of switching device. The outputs are prot ec ted from driving
inductive loads. Enabling the us e of these output channels is a factory
programmable opt ion only.
Access to the control outputs is through a 6-pin polar iz ed connector on the controller
board. If t he s y stem is ordered with any c ontrol outputs enabled, a matching
connector is pr ov ided. This connector has three wires, red is connec ted to the
12VDC power supply c ontinuously, purple is the output for channel one and white is
the output for channel two. If any high cur r ent 12 volt power supply connections are
required, t hey s hould be tied directly t o the bat tery terminals or s om e other low
impedance power or ground source. High s w itching currents s hould not be sent
through the c ontroller board.
The contr ol outputs can be turned on and off via commands sent through one of the
databases and the current status of t he outputs is shown in all transm itted data.
The radio modem must be turned on to receive the cont r ol c om mands from the
satellite. In cases of low batter y v oltage, the radio may be shut of f by the power
management sy s tem to conserve power and will not receive any tr ans m iss ions .
More about t he power consumption is discuss ed in another section of this manual.
In solar powered s y s tems, care must be taken to ensure that the system will have
sufficient power at the t ime acc es s to control outputs is needed. With AC powered
systems, power failure must also be cons ider ed, although the battery may provide
backup power for s ev er al hour s or m or e depending on configuration.
There is a var iable time delay between the control command being s ent and the time
that action is taken; this is called the latency time. Global Water has no over latenc y
time, the operation of the Orbcom m sat ellite network or any of the ser v ers involv ed in
relaying data t o or from our database. While the transmiss ion of sensor data and
commands is r eliable, it’s possible t hat gaps in transmissions c ould oc c ur and cause
commands to be delayed or missed entirely. It is strongly reco mmended that the
control ou tput s no t be used in cases w here life or property cou ld be
threatened by the failure of the outputs to operate. Global Water is not
responsible for dam age caused by failur es when us ing this featur e.