Download AGILENT 34401A Limit Testing

AGILENT 34401A Limit Testing
The limit test operation enables you to perform pass/fail testing to upper and lower limits that you specify.
Getting Started
Allowable Functions
Limit test will work with DC Voltage, AC Voltage, DC Current, AC Current, 2 Wire Ohms, 4
Wire Ohms, Frequency, Period, and Ratio measurements. (All measurement functions except
Continuity and Diode.)
Upper Limit
The upper limit can be set to any value between 0 and ±120% of the highest range, for the present
function. The upper limit selected should always be a more positive number than the lower limit.
The default upper limit is "0".
Lower Limit
The lower limit can be set to any value between 0 and ± 120% of the highest range, for the present
function. The default lower limit is "0".
Audio Warning
The AGILENT 34401A will emit a tone whenever a limit is exceeded in a limit test. The frontpanel beeper can be disabled--refer to the section titled "Beeper Control" in Chapter 3 of the
AGILENT 34401A User's Guide.
Front Panel Example
Enable the limit test to warn of DC Voltage measurements above 3 Volts and below -5 Volts.
1.
Select the measurement function. Press the [DCV] key on the front panel to select DC Voltage
measurements (this is the default).
2.
Set the upper limit. Turn on the menu by pressing [SHIFT][On/Off]. You should see A: MEAS
MENU. Press the right arrow key; the display should change to show B: MATH MENU. Press the
down arrow once, then the right arrow until you see 6: HIGH LIMIT and press the down arrow
again. Enter in the value 3 Volts using the left and right arrow keys to select the digit, and the up
and down arrow keys to change the value of that digit. To change the range, highlight the voltage
term at the right and increase or decrease using the up and down arrow keys. Press the [ENTER]
key to save the change and exit the menu.
3.
Set the lower limit. Now that you have adjusted the upper limit, you can press [SHIFT][Recall] to
re-enter the menu at the last parameter you adjusted (6: HIGH LIMIT). Press the right arrow once
to select 7: LOW LIMIT and press the down arrow to modify the parameter to read -5 Volts. Press
the down arrow key twice to change the sign first to positive, then to negative. Press [ENTER] to
save the change and exit the menu.
4.
Enable the limit test. Press [SHIFT][Recall] to re-enter the menu at the last parameter adjusted
(7: LOW LIMIT). Press the left arrow twice to select 5: LIMIT TEST and press the down arrow to
modify the parameter. Use the right or left arrow keys to toggle between OFF and ON. Select ON
and press [ENTER] to save the change and exit the menu. The MATH annunciator on the display
will be lit.
When a signal is applied to the meter terminals, the signal is first measured and then the limit test is
performed. The multimeter displays "OK" for each reading that is within the specified limits. It displays
"HI" or "LO" for each reading that exceeds the upper or lower limit. If the front-panel beeper is enabled
(default), the multimeter will beep once on the first occurrence of a failed reading after a good reading.
Programming Example
Below is a sample program in BASIC for the front-panel example. The example set up a limit test on DC
Voltage measurements with an upper limit of 3 Volts and a lower limit of -5 Volts.
10 !
20 CLEAR 7
! clear GPIB and AGILENT
34401A
30 ASSIGN @Dmm TO 722
! assign I/O path
40 OUTPUT @Dmm;"*RST"
! reset the AGILENT 34401A
50 OUTPUT @Dmm;"*CLS"
! clear status registers
60 OUTPUT @Dmm;"CONF:VOLT:DC DEF,DEF" ! configure DC Voltage
70 ! set up limit test
80 OUTPUT @Dmm;"CALC:FUNC LIM"
! math function is limit
90 OUTPUT @Dmm;"CALC:LIM:UPP 3"
! upper limit is 3 Volts
100 OUTPUT @Dmm;"CALC:LIM:LOW -5"
! lower limit is -5 Volts
110 OUTPUT @Dmm;"CALC:STAT ON"
! limit test enabled
120 ! set up triggering
130 OUTPUT @Dmm;"TRIG:SOUR IMM"
! immediate triggering
140 OUTPUT @Dmm;"INIT"
! initiate 1 reading
150 END
If you wish to bring readings across into the computer, replace line 140 with the following two lines:
140 OUTPUT @Dmm;"READ?"
! place reading on buffer
142 ENTER @DMM;Value
! store reading in variable
Consider The Following
Pass/Fail Output Signals
There are two unused pins on the RS-232 interface connector which are available to indicate the pass/fail
status of readings taken with limit testing. A low-going pulse is output to pin 1 for each reading that is
within the specified limits. A low-going pulse is output to pin 9 for each reading that exceeds the upper or
lower limit.
To configure these pins for limit testing, you must install two jumpers inside the
multimeter. Instructions to connect these signals are provided in the AGILENT 34401A
Service Guide. Do not use the RS-232 interface if you have configured the multimeter to
output pass/fail signals. Internal components on the RS-232 interface may be damaged.
The GPIB interface is not affected.
Service Request (SRQ)
The AGILENT 34401A can be configured to generate a service request (SRQ) on the first occurrence of a
failed reading. Refer to the section titled "The SCPI Status Model" in Chapter 4 of the AGILENT 34401A
User's Guide.