Keithley 172 Instruction Manual page 21

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INSTRUCTION MANUAL
OPERATING INSTRUCTIONS
I
Dlgllal Mulllmeler
Models
172. 173
FIGURE
8.
Front Panel Pushbutton Selection.
3-4.
HOW TO SELECT RANGE.
The Model 172/173 provides automatic or manual ranging.
The
AmO/M4N pushbutton determines the ranging mode, where AUTO = fully automatic ranging.
a. AUTO.
When released
, the Model 172/173 automatically selects the appropriate
range in accord with the following rules.
I. When the display exceeds 29999 the Model 172/173 upranges (that is, it changes
to less sensitivity and the decimal point moves appropriately).
2.
When the display reaches 02599 the Model 172/173 downranges (that is
it changes
to greater sensitivity and the decimal point moves appropriately).
b. MAN. When depressed the range is placed in hold. The user can cause the Model
172/173
to uprange or downrange by using the UP RANGE and DN RANGE pushbuttons.
1. When DN RANGE is momentarily depressed the Model
172/173
will downrange one
decade of sensitivity. Each time the pushbutton is depressed and released, one
downrange will occur until most sensitive range is obtained.
2. When UP RANGE is momentarily depressed the model 172/173 will uprange one decade
of sensitivity. Each time the pushbutton is depressed and released, one uprange will
,occur until least sensitive range is obtained.
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AA
3-3