HP 3457A Service Manual page 51

3-42. Input Selection. When using the General Purpose Multiplexer, the instrument must be set for Rear or
Scanner inputs.
© To select Rear Inputs - Press the TERM / M configuration key. Use the }/AUTO or }/HOLD scroll key
to display REAR or SCANNER and press the ENT / LAST ENTRY key.
3-43. Channel Selection. Only one input channel, either 2-wire or 4-wire, plus one actuator channel can be
selected at a time. When an input channel is closed, the channel previously closed is opened. The same ap-
plies to the actuator channels.
© 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 close one of the actuator channels - Press the Blue SHIFT key then the OFFSET COMP / C key, Use
the }/HOLD scroll key to display CLOSE. Enter the number of the actuator channel to be closed (8 or 9)
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.
3-44, 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 7 of the
HP 44491A Multiplexer.
© Determine the type of measurement you wish to make (Voltage, Resistance, Current, 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 t/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 > display key once to hold the command.
Use the f/AUTO or |/HOLD scroll key to display HOLD:4 and press the ENT / LAST ENTRY key.
© Set the number of readings for the number of measurements to be made (in this case 8) - Press the
NRDGS / L configuration key, enter the number 8 and press the ENT / LAST ENTRY key.
© Set the Scan Advance to Auto - Press the SCAN ADV/O configuration key. Use the [/AUTO or
}/HOLD scroll key to display AUTO:2 and press the ENT / LAST ENTRY key.
© Enable the Reading Memory - Press the CONFIG / P configuration key then the ENT / LAST ENTRY
key.
© Allocate Reading Memory space (each reading requires 4 bytes of memory) - Press the Blue SHIFT key
then the TERM / M configuration key. Use the |/HOLD scroll key to display MSIZE. Enter the number
32 (8 readings times 4 bytes) and press the ENT / LAST ENTRY key.
© Select the channels to be measured - Press the Blue SHIFT key then the RECALL / S configuration key.
Use the {/HOLD scroll key to display SLIST. Enter the number of each channel you wish to measure fol-
lowed by a comma
(,) to separate them (example: 0,1,2,3,4,5,6,7). Press the ENT / LAST ENTRY
key. (4s
many as 16 single digit channel numbers or 8 double digit channel numbers can be entered at one time. The number of read-
ings (NRDGS) should be set for the number of channels entered ).
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