TeeJet ARC-6000 - Manual (Page 42)

98-05017
Rev.- 1
B-4
ARC 6000
CE & S
TANDARD
V
ERSION
Sometimes an applicator is already equipped with a flowmeter. The ARC system can usually be adapted to work with
existing flow meters, as long as they measure the total liquid flow. Check with your MID-TECH dealer, or the factory,
regarding the adaptability of a specific flowmeter. Note: Some flowmeters may require a special adapter cable.
When an ARC system is operating in the pressure based mode, a pressure sensor is used to determine rate of flow, rather
than a flowmeter. Knowing the characteristics of the nozzles being used, the console can determine the flow rate of the
liquid by monitoring the pressure in the boom line.
B.2.2.2. LIQUID OR GRANULAR APPLICATION
Some ARC control systems require an application rate sensor to measure flow. Rate sensors are devices used to measure
the rotation of either a liquid pump or a conveyor feed shaft. Using a rate sensor, each rotation of the pump or shaft is
related to the discharge of a specific volume of material.
The most successful rate sensors are usually the slotted disk type, giving 60 to 360 signals per revolution of the pump or
shaft. Rate sensors which give only a few signals for each revolution are usually not precise enough for MIDWEST
TECHNOLOGIES controllers.
B.2.3. FLOW CONTROL VALVE
All ARC systems require a flow control valve to provide automatic rate control. The console uses this valve to throttle
flow rates in response to commands from the control console. To be effective in controlling flow, this valve must be
both fast acting and precise in its movements.
Flow control valves may be straight through or auto-ranging valves (poly or stainless); or they may be hydraulic valves
controlling the speed of a hydraulic motor driving a separate liquid pump.
Sometimes an applicator is already equipped with an electronically controlled flow control valve. If the valve meets the
speed and precision requirements of the ARC system, it can be adapted for use. Check with your MID-TECH dealer, or
the factory, regarding the adaptability of a specific valve.
B.2.4. GROUND SPEED SENSOR
ARC requires an accurate ground speed sensor. A magnetic pickup wheel sensor can be used. This sensor, mounted on
a non-driven wheel, has proven to be very accurate and dependable for most spraying operations.
An optional radar ground speed sensor is available from MIDWEST TECHNOLOGIES for applications where wheel
slippage and variations in ground conditions are a concern. The radar sensor does not depend on ground contact and is
unaffected by these variables.
Some applicators may already be equipped with a ground speed sensor. If the speed sensor meets the accuracy require-
ments of the ARC system, it can be adapted for use with the ARC control console. Check with your MID-TECH dealer,
or the factory, regarding the adaptability of a specific sensor.
B.2.5. BOOM INTERFACE
The ARC control console needs to know when each boom section is activated, in order to adjust chemical flow rates
appropriately. The console recognizes the activation of each boom section, whenever it receives a positive voltage on the
boom interface connection corresponding to that boom position. The console is capable of sensing and responding to
nine separate boom sections. The console can also sense the operation of an independent, status switch which would
result in a selectable response by the Flow Control valve (position held or full closure). Finally, the Boom Interface can
be equipped with an optional Ground Speed Override switch which, when activated, will cause the control console to
ignore the ground speed sensor and use only a pre-selected "OVERRIDE SPEED" to control the operation of the Flow
Control valve.
The standard ARC system is supplied with a five position boom interface cable. The cable plugs directly into the rear of