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 millisec-
onds.
It is important that the user be thoroughly familiar with the contents of this manual be-
fore performing any tests on radiation generating equipment. It is also imperative that
the user be thoroughly qualified, and familiar with safety precautions and other practic-
es 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 the 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 the 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.
