HP 3457A Service Manual page 52

Operation 3457A
* Make the measurement - Press the SINGLE / F configuration key to start the measurement sequence.
The instrument will read each channel listed and store the readings in memory.
© Recall the readings - Press the Reading Memory RECALL / S key then the ENT / LAST ENTRY key.
The reading displayed is the last reading taken. The readings are shifted into memory so that the first
reading taken is in the highest number memory location. The last reading taken is in memory location |.
Use the {/AUTO and |/HOLD scroll keys to view the measurement readings. Use the </TEST and
/RESET display keys to read the total display contents.
¢ To repeat the same set of measurements - Press the CONFIG /R configuration key then the
ENT / LAST ENTRY key to clear the reading memory. Press the SINGLE / F configuration key to start
the new reading sequence.
3-45. HP 44492A Reed Relay Multiplexer (Manual Operation)
3-46. The HP 44492A Reed Relay Multiplexer has ten 2-wire input channels numbered 0 through 9, This
multiplexer is used to make voltage, resistance and frequency or period measurements, It is not designed to
make 4-wire ohms or current measurements.
3-47. Measurement Selection. Determine the type of measurement you wish to make (Voltage, Resistance
or Frequency/Period) and set the instrument for that measurement as described in the previous paragraphs.
3-48. Input Selection. To use the Reed Relay Multiplexer, the instrument must be set to the Rear/Scanner
input.
© Select the Rear/Scanner input - Press the TERM / M configuration key. Use the [/AUTO or |/HOLD
scroll key to display REAR:2 or SCANNER:2 and press the ENT / LAST ENTRY key.
3-49, Channel Selection. Only one input channel can be selected at a time. When an input channel is
closed, the channel previously closed is automatically opened.
© To select an input channel - Press the CHAN / N configuration key, enter the number of the channel to
be closed and press the ENT / LAST ENTRY key.
© To open all channels - Press the Blue SHIFT key then the OFFSET COMP / C key. Use the }/HOLD
scroll key to display CRESET and press the ENT / LAST ENTRY key.
3-50. Scanning. The instrument can be set to automatically take a number of readings and store them in
memory. This makes it possible to measure some or all of the input channels and recall the measurements
taken. The following is a simple procedure to measure inputs connected to channels 0 through 9 of the
HP 444924 Reed Relay Multiplexer.
© Determine the type of measurement you wish to make (Voltage, 2-Wire Resistance, Frequency/Period)
and set the instrument for that measurement as described in the previous paragraphs.
® Select the Rear/Scanner input - Press the TERM / M configuration key. Use the }/AUTO or {/HOLD
scroll key to display REAR:2 or SCANNER:2 and press the ENT / LAST ENTRY key.
© Set the Trigger to Hold - Press the Blue SHIFT key then the STORE /T configuration key. Use the
{/HOLD scroll key to display the TRIG command. Press the +/RESET display key once to hold the com-
mand. Use the t/AUTO or | /HOLD scroll key to display HOLD:4 and press the ENT / LAST ENTRY key.
© Set the number of readings to match the number of measurements to be made (in this case 10) - Press
the NDRGS / L configuration key, enter the number 10 and press the ENT / LAST ENTRY key.
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