User Manual

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1077 Technical Manual Page | 9
4.2. Checki ng/Calibrati ng t he Tra ns duc e r
By selecting the 'line' simulation mode on the 1077, the 1077 acts as the 24V D. C. supply
and the current meter, any current taken from the 24V acros s the 1077 terminals will be
registered on the L.C.D. meter.
The current taken by a transducer can therefore be easily checked by connect ing t he
transducer directly to the 1077 and then reading the current shown on the meter.
4.3. Checki ng/Calibrati ng t he Re c order
By selecting 'Source' mode the 1077 will supply the necessary voltage to drive the current
set on the thumbwheel switches through the recorder, should the voltag e required to drive
the set current be greater than the maximum voltage the 1077 can pr oduce, the 'voltage
limit' light illum ina tes indicating that the set current is not being driven.
The current meter/recorder can be checked by driving in set currents and observing the
corresponding deflection.
4.4. Test/ Ca li brate Current Me t er/ Re corder and Power Unit
The 'Load' mode of the 1077 simulat es the transducer in which the current set on the
thumbwheel switches is taken from an externally applied voltage, which must be between 3
and 30 volts. In this mode it is possible to disc onnect the transducer from the loop and
connect, in its place, the 1077; the current registered on the r ec order being the current set
on the 1077. In this way the power unit, recorder and wiring of the loop are checked.
4.5. Setting the Output Volt a ge
The maximum terminal voltage the 1077 will supply in any mode can be set by the ‘Output
Voltage Control’.
To adjust remove the 1077 f r om t he carrying case and locate the Output Voltage adjustment
to the right of the Battery Level Indicator (a sm all scr ewdriver will be necessary if adjustment
is required).
Turn on the 1077 and select line mode. Turn the output on and measure the ter minal
voltage with a voltmeter. Adjust to new voltage with output voltage control if required.
Note 1: This control also sets the m aximum terminal voltage that will be applied in the
Source mode.
Note 2: The maximum output voltage at 100mA will be 24V (.1A x 24V – 2.4 watts)
regardless of the setting of the Output Voltage control.