First encounters
3.3.2.1 Connections
The HCU provides
•
two identical 26-pin, military-specification bayonet
connectors for attaching to the
HCU
or
RECORDER
connectors of the breakout box, and
•
a 10-pin, military-specification bayonet connector
through which you can power the instrument, if
desired. The power pins on this connector are
directly connected to those on the
SENSOR POWER
connector of the breakout box. When using this
alternative power connection, you should ensure you
do not inadvertently connect two power supplies
together.
3.3.2.2 Signal meter
The upper section of the HCU contains a simple voltmeter
for monitoring various signals from the instrument.
•
To monitor the velocity outputs, switch the dial to
V,
N/S
or
E/W
VEL
according to the component you want to monitor.
•
To monitor the mass position outputs, switch the dial to
V, N/S
or
E/W
MASS
POS
according to the component you want to monitor.
•
You can set the range of the meter with the
RANGE
switch. When switched to
10 V, the meter ranges from –10 to +10 V (as marked). When switched to 1 V,
the range is –1 to +1 V.
3.3.2.3 Calibration and control
You can calibrate a 3TB sensor through the HCU by connecting a signal generator
across the yellow and green
CALIBRATION SIGNAL
inputs. The
CAL ENABLE
dial
must be set to 'V' – the 3TB has only one calibration enable line and this acts on all
components simultaneously. The sensor's response can now be monitored or
recorded, and calibration calculations carried out.
The section of the HCU below the calibration lines controls the instrument's mass
control system. To initiate locking, unlocking, or centring, hold down the
ENABLE
switch on the HCU
together with
the appropriate switch for the command you want
to issue for at least six seconds.
3.3.2.4 Banana plugs
The remainder of the HCU provides useful connections for each of the signal lines
from the instrument, for attaching to your own equipment as necessary.
15
Issue G - November 2019
