Time Electronics 1077 Milliamp Transducer Simulator - Manual (Page 9)

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1077 Technical Manual P a g e | 9
4.2. Checking/Calibrating the Transducer
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 across the 1077 terminals will be
registered on the L.C.D. meter.
The current taken by a transducer can therefore be easily checked by connecting the
transducer directly to the 1077 and then reading the current shown on the meter.
4.3. Checking/Calibrating the Recorder
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 voltage required to drive
the set current be greater than the maximum voltage the 1077 can produce, the 'voltage
limit' light illuminates 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/Calibrate Current Meter/Recorder and Power Unit
The 'Load' mode of the 1077 simulates 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 disconnect the transducer from the loop and
connect, in its place, the 1077; the current registered on the recorder 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 Voltage
The maximum terminal voltage the 1077 will supply in any mode can be set by the ‘Output
Voltage Control’.
To adjust remove the 1077 from the carrying case and locate the Output Voltage adjustment
to the right of the Battery Level Indicator (a small screwdriver will be necessary if adjustment
is required).
Turn on the 1077 and select line mode. Turn the output on and measure the terminal
voltage with a voltmeter. Adjust to new voltage with output voltage control if required.
Note 1: This control also sets the maximum 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.