81233-4r1
Page 7 of 9
7 Input and Output Connections
7.1
Monitoring and Control
7.1.1 HV enable
This is a digital input which controls the HV output. Driving this input low (< 0.8V)
will cause the HV output to be enabled and ramp up to its programmed value. The
filament current will start to ramp up after the high voltage has reached its
programmed value, approximately 3 seconds after the HV output is enabled.
Disconnecting or driving this input high (>2.4V ) will cause the filament to be turned
off and the HV output disabled. The maximum input voltage of this input is 12V.
7.1.2 Filament stable
Open collector digital output indicating that the filament current has stabilised and
the tube could be producing X-rays. This should occur 8
–
10s after the HV enable is
activated. A low output (<0.8V) indicates that the filament current has not stabilised
The maximum rating of this input is 12V.
7.1.3 HV voltage program output
A 10V internal
reference voltage and 12 turn 20KΩ potentiometer is provided that
can be used to locally control or pre-set the high voltage output. Connecting this
output to the high voltage program input will allow the high voltage output to be pre
set/controlled using the internal potentiometer.
7.1.4 HV voltage program input
0
–
10V input corresponding to 0
–
10kV output. Ac/-2% of full scale. Z
in
=
5MΩ.
7.1.5 HV voltage monitor
0
–
10V output corresponding to 0
–
10kV output. Ac/-2% of full scale. Z
out
=
10kΩ.
7.1.6 Emission current monitor
0
–
10V output corresponding to 0
–
1mA emission current. Ac/-3% of full
scale. Z
out
= 10kΩ.
7.1.7 Filament current monitor
0
–
10V output corresponding to 0
–
5A filament current. Ac/-5% of full
scale. Z
out
= 2k2Ω.
7.1.8 Filament current Pre heat (set value)
Provided for adjustment of the filament Pre heat current level. 0
–
5V output
corresponding to a Pre heat current setting of 0.5A
–
2.5A filament current.
7.1.9 Filament current Preset Maximum filament current (set value)
Provided for adjustment of the filament current limit value. 0
–
10V output
corresponding to a maximum filament current of 0
–
5A.
7.1.10 Emission current program input
0
–
10V input corresponding to 0
–
1mA emission current. Ac/-3% of full
scale. Z
in
= 1MΩ.
7.1.11 Emission current program output
A 10V internal reference voltage and 12 turn 5KΩ potentiometer is provided that can
be used to control or pre-set the emission current. Connecting this output to the
emission current program input will allow the emission current output to be pre-set
using the internal potentiometer.
7.1.12 Pin connections
The monitoring and control is provided through a 15 way ‘D’ connector which also
provides input power to the unit.
