Electronic Control Concepts 8700 Instruction Manual

MODEL 8700

X-RAY PULSE COUNTER / EXPOSURE TIME METER

INSTRUCTION MANUAL

TABLE OF

CONTENTS

OVERVIEW 2

DESCRIPTION

GENERAL INSTRUCTIONS

BATTERY REPLACEMENT

WARRANTY

CALIBRATION

SERVICE INFORMATION

EXPOSURE TIME CONVERSION CHART

SPECIFICATIONS

APPENDIX

2

3

5

5

5

5

6

7

8

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OVERVIEW

This instruction manual applies to Electronic Control Concepts Model 8700 for Serial
Numbers 7001 and above. Significant design improvements have been made to this
version of the Model 8700 including:

1)Ability to measure pulsed x-ray time in milliseconds as well as count pulses.

2)Improved sensitivity which means that we can measure exposure time of very low
level x-rays.

3)Improved x-ray intensity range allows use with high energy x-rays.

4)Exposure time accuracy is now 1%.

5)Multi character display makes operation and unde rstanding of results easier.

DESCRIPTION

The ECC Model 8700 X-ray Timer/Counter is used to measure the duration of radiation
output produced by X-ray generators. The ECC Model 8700 is a solid-state, digital in­strument designed specifically for service personnel in assessing the performance of
radiation generator timing controls. The instrument is a noninvasive instrument, which
samples the radiation beam of x-rays.

The Model 8700 can be used as follows:

1) To count the number of x-ray pulses produced by half-wave and full-wave recti­fied machines. It will count the output pulses typically 60 pulses per second for
half-wave rectified machines or 120 pulses per second for full-wave. Dental x­ray machines are usually half-wave rectified.

2) To measure the exposure time of x-ray pulses produced by half-wave and full­wave x-rays. This is a new function, and is the only Exposure Time Meter avail­able with this capability.

3) To measure the length of radiation output when the x-ray output is stead y state
such that "pulsing" does not exist. X-rays that generate steady outputs include
3-phase AC medical x-ray machines; capacitor discharge x-ray machines and
DC operated x-rays.

4) To measure the "on time" or relay contact closure time by counting the number
of pulses of AC line voltage (90 to 130 VAC) via the front panel input jacks and
test leads.

The Model 8700 replaces not only mechanical impulse counters, but also othe r elec­tronic counters. The small hand held size conveniently fits in a small toolbox, jacket
pocket or handbag.

There is no "Reset" button. The Model 8700 automatically resets at the beginning of
each exposure, holding the reading until the next exposure.

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The most convenient way of using the 8700 is to place it directly under the x-ray head,
step back, take the exposure and then read the exposure time in pulses or millisec­onds.

It is important that the user be thoroughly familiar with the contents of this manual be­fore performing any tests on radiation generating equipment. It is also imperative that
the user be thoroughly qualified, and familiar with safety precautions and other practic­es relating to radiation generators.

GENERAL INSTRUCTIONS

Switch Settings

The front panel selector toggle switch on the Model 8700 has 3 positions, 'OFF',
'PULSES", and "MILLISECONDS'. The switch is OFF in the center position.

PULSES
When the switch is moved to the 'PULSES' position, the instrument will be used for
measuring (or counting) output pulses from half-wave or full-wave rectified machines as
well as AC line voltage pulses. Normally (in USA), each full second of exposure will
produce 60 pulses. An exposure of 2/10 second will read 12 for example. Refer to the
chart on page 5 for further illustration.

MILLISECONDS
With the switch in the 'MILLISECONDS' position, the instrument will measure the length
of time that a DC or 3-phase AC x-ray is on. The display reading will be in milliseconds
i.e. an exposure of 1 second will read 1000, an exposure of 2/10 second will read 200.
This switch position can also be used for measuring the exposure time of pulsed x-rays.

OFF
All power to the instrument is disconnected in the 'OFF' position. Set the switch to
'OFF' when not in use to conserve battery life. The center position is OFF.

Connections
When reading directly from an x-ray head, no connections are made to the instrument.
Point the x-ray head at the "target" area of the Model 8700. Take an exposure and
read the time on the display in pulses or milliseconds.

AC Input
Connect the test leads to the two input jacks on the front of th e instrument. Since the
instrument counts AC pulses, the AC line must be switched by the relay that is in the
timer under test. A typical wiring configuration is shown in schematic form in Figure 1.
A typical wiring configuration for testing an ECC Model 8200A Timer is shown in Figure

2. When using the AC mode, the switch must be in th e PULSE position.
The circuit for AC inputs is completely isolated from the rest of the instrument. No

damage to the instrument will occur if the probes are reversed. If the count is off by
one pulse, try reversing the leads.