Time Electronics 1051 Resistance Decade Box - Manual (Page 4)

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1051 Technical Manual 3
2.
Operation of the 1051
The 1051 is a compact, robust and accurate decade resistance box and will find many
applications in both industry and education. With its low resistance ranges the 1051 is
particularly suitable for simulation of platinum resistance thermometers.
It is imperative that the switch setting should be unambiguous in order to avoid misreading
the set value. To prevent misreading, the 1051 incorporates a unique colour coding system
to divide the setting into 3 groups corresponding to milli-ohms, ohms and kilo-ohms.
Resistance is simulated by dialing the value required using the thumbwheel switches.
This enables precise setting with a clear unambiguous indication.
For example - to simulate a PT100 element at 100ºC this would be 138.50
Ω.
• Set the 100 Ω bank to 1,
• the 10 Ω bank to 3,
• the 1 Ω bank to 8,
• the 0.1 Ω bank to 5 and
• the 0.01 Ω bank to 0.
Connection to the box is via 4 mm banana plugs. Two connections red and black connect to
the resistance and the green terminal connects to the case for screening purposes.
Special attention has been given to the problem of reliability of operation. A special multiple
gold contact switch arrangement ensures that a back-up contact is always available to take
over should a failure occur.
Note: Remember that all resistance boxes have a residual resistance, i.e. when the dials
are set to zero a small resistance remains. If you are making precision measurements or
recalibrating the instrument, this residual value must be subtracted from all measurements.