Cooper Instruments RANGER 5 User Manual

RANGER 5 TRANSDUCER SIMULATOR OPERATING INSTRUCTIONS

The Ranger 5 Transducer Load Cell Simulator is a valuable and versatile diagnostic tool,
designed by people who use simulators day in and day out for their own use. It will give you years
of precision s ervice if you take a few minutes to learn how to use and maintain it.

What is a Load Cell Simulator? Simulators provide a convenient, repeatable way to generate
signals identical to those that strain gauge load cells and pressure transducers produce when

load is applied to them. These signals can then be used to calibrate or test indicators, amplifiers,
or power supplies with a known stable signal.

What kind of signals will I get out of the Simulator? Simulators, like the load cells they
simulate, are pas sive devices. You don't get anything out until you put something in. What you

put in is the Excitation Voltage. The output of the simulator is proportional to the signal applied. If,
for example, we "excite" the simulator with 10.00 VDC with the selector s witch set to 1.00 mV/V,
the output would be 10 X 0.001 = 0.010V or 10 mV. If we change the excitation to 15.00 VDC,
then the output would be 15 X 0.001 = 0.015V or 15 mV. The simulator always provides a signal,
which is proportional to the input voltage. Precision simulators, such as the Ranger 5, can be
used with a precision power supply to provide a laboratory source of millivolt reference.

What kind of cells can I simulate? The Ranger 5 main bridge is set for 350Ω cells, the industry
standard. The simulator can also be used to test instrumentation connected to 240Ω, 400Ω ,
700Ω, 1000 Ω or 3000Ω cells, provided the excitation supply can excite one 350 ?Ω bridge.
Compute the current required to excite the bridge by using the following formula:

Indicator Excitation Voltage / 350. = Bridge Current in amps

Example: if we have an indicator with a 5VDC excitation voltage, then (5 VDC) / (350.) =

0.0143 A. The Ranger 5 will work with this system if the excitation supply can provide
more than 0.014 A (14 mA).

The power-loading switch of the Ranger 5 also allows loading the power supply of an indicator
with up to 8 - 350Ω cells or 16 - 700Ω cells.

What excitation voltages can I use? The Ranger 5 was designed for use with excitation
voltages of 5 VDC - 15 VDC. The maximum excitation voltage must not exceed 15 VDC!

Can I use Ranger 5 with AC excitations? Bridge simulators like the Ranger 5 will work with
many low frequency AC excitation supplies of ± 7.5 VAC or lower. The switching frequency
should be less than 100 Hz for best results. Caution: Certain AC excitation instruments are very
sensitive to inductive loading. The Ranger 5 uses very stable wire-wound resistors that are
designed to minimize induction. However, some induction is present and may cause problems
with some meters.

Can I use the simulator in wet or dirty environments? - The construction materials of the
Ranger 5 were carefully selected to make the simulator accurate and rugged. The rotary switches

are all environmentally sealed. If the simulator is used outdoors in rain or snow, excessive

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moisture can build up around components and cause leakage. This doesn't damage the
simulator; just dry it out. Use a desiccant inside the simulator if the unit is left outdoors for
extended periods of time. Clean the simulator by wiping off the face with a soft cloth or use
isopropyl alcohol wipes. If you fear contamination has gotten under the front face, remove the
four stainless steel screws on the corners and remove the simulator assembly. Clean the inside
of the enclosure and reassemble.

What kind of cables should I use? Load cell simulators should be wired like load cells. Use
shielded load cell wire with the shield connected at the indicator and unconnected at the

simulator. Important: If the indicator has any kind of remote sensing capability, use it! Make your
standard cables six-wire cables. Use # 22 A.W.G. or # 20 A.W.G. cable if possible. Connect the
+Excitation and the +Sense to the +EXC terminal on the simulator. Connect the -Excitation and
the -Sense to the -EXC terminal on the simulator. The simulator can then simulate a six-wire
system and verify that the sense amplifiers are working on the meter.

What kind of accuracy can I expect from the simulator? The simulator has characteristics
equal to or better than a strain gauge load cell. The background noise of the simulator is

approximately 250 nV. The temperature coefficient of the simulator is less than 5 ppm/°C with
bridge tracking of < 1 ppm/°C. The linearity of the simulator is always <±0.05% of full scale and
<±0.02% in most cases. The repeatability is <±0.01% of full scale. The absolute accuracy of each
step is ±0.05% of full scale. A detailed calibration report for the individual simulator is available for
a nominal charge.

A stable, repeatable simulator can be invaluable in many situations. No scale inspection or test
should be complete without a detailed simulator test. The data should be recorded at the
customer's site and in the service agency's permanent record about this scale and installation.
The information must include the serial number of the simulator used to make the test. If the
indicator should fail, or be damaged by lightning, the system can be returned to operation with the
same simulator until a test truck can arrive.

What are all the knobs and buttons about? Every control and function has been carefully
designed to be useful for technicians who work with strain gauge and pressure transducer
instrumentation. The value of calibrated steps cover the ranges used with almost any scale

installation.

• Carefully calibrated 1.75, 2.00 and 3.00 mV/V outputs duplicate the most common
outputs of cells.

• The full range from 0-3.00 mV/V with 0.25 mV/V steps allows testing meter linearity at
several steps along the calibration curve. The calibrated +0.25 mV/V deadload offset is
required for many newer meter designs that require a significant deadload at zero for
proper digital calibration.

• The multi range vernier allows easy, stable adjustment between steps. This helps the
technician test multiple setpoints in even the most complex batching routines. The six-way
binding posts accept cables or connectors. All metal parts are stainless steel and the
entire simulator is constructed so that the enclosure can be easily replaced if damaged.

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