Keithley 705 Instruction Manual page 23

card which is field installable in the Model 705 Scanner main-
frame. The card is capable of switching up to 10 channels. For
low level tranducer and thermocouple output switching, the
Model 7059 is designed to introduce a minimum of thermal
voltage error ( ( IpV input to output with copper leads) and en-
sure that high isolation (lOl*D) is maintained between input
signals. Quick disconnect screw terminals are used to facilitate
input and output connections to the scanner plug-in card.
The actual measurement of the low voltage should be done
with a high quality microvoltmeter such as the Keithley Model
177 or the Model 181 digital nanovoltmeter. These instruments
are capable of measuring in the range of microvolts with high
accuracy. To measure such low voltage a number of measur-
ment parameters must be taken into consideration. The meas-
urement parameters include source resistance, thermal emf's
ground loops etc. While this example does not attempt to
educate the user in low voltage measurements, the instruction
manual provided with each of the previously mentioned in-
struments gives step by step instructions on how to measure
low voltage accurately.
For detailed information concerning the Model 7059, refer to
the Model 7059 Instruction Manual, document number
7059-901-Ol A. In this example, it will be assumed that the user
needs to scan five separate voltage sources, Also, the follow-
ing parameters will be programmed into the Model 705.
1. First channel is 1.
2. Last channel is 5.
3. Interval time is one second.
4. Use the single scan mode.
Use the following procedure to program the Model 705 for this
example:
1. Assume that there are five low voltage sources to be scann-
ed. Connect the five low voltage sources to the Model 7059
via the quick disconnect screw terminals located on the
card.
2. Install the Model 7059 into the Model 705 Scanner main-
frame. Refer to paragraph 2.2.2 for scanner card installation
instructions.
3. Select the appropriate line voltage and turn on the Model
705. Refer to paragraphs 2.2.1 and 2.3 respectively.
4. Press 0, 1, FIRST. (Programs channel 1 as the first
channel.)
5. Press 0, 5, LAST. (Programs channel 5 as the last channel).)
6. Press INTERVAL, O,O, 1, 0, 0, 0, ENTER. (Programs the in-
terval time for one second.)
7. Press CHANNEL, RESET. (Turns on the CHANNEL LED,
selects the channel mode for display and resets the Model
705 to the programmed first channel.)
8. Press SINGLE. (Selects the singl'e scan mode and turns on
the SINGLE LED.)
9. Press START/STOP. (Initiates the single scan mode and
turns on the START/STOP LED.)
Upon actuation of step 9 the Model 705 scans through the pro-
grammed channel at the programmed interval rate one time.
As in the previous examples, the scanning sequence can be
stopped at any programmed channel by simply pressing the
START/STOP button. Pressing the START/STOP button
during a scan stops the sequence at the presently displayed
channel, the channel remains closed, and turns off the CHAN-
NEL LED. To resume the scanning sequence from the present-
ly displayed channel, press the START/STOP button. The
START/STOP LED turns on when resuming the scan.
To stop the scanning sequence and reset the Model 705 to the
programmed first channel, simply press the RESET button.
The parameters that were programmed into the Model 705 for
this example were chosen at random. The parameters can be
easily changed to suit the particular measurement and/or
scanning configuration at hand by reprogramming the Model
705.
OPERATING THE CLOCK
The CLOCK group on the Front Panel contains the TIME and
DATE buttons. The clock continues to run after the Model 705
is powered down. This is because the clock's power circuitry is
backed up by battery BTlOl . The time is displayed in a 24 hour
display, refer to paragraph 2.5.2 step 6 for time display format.
The date is displayed in one of two formats (See paragraph
2.5.2 step 6). To display the time mode simply press the TIME
button. To set the time, use the following procedure:
1. Press TIME (selects the time mode for display and turns on
the time LED).
2. Press the DATA buttons (O-9) that correspond to the
desired time: For example, to set the time of 7:30 A.M.
press 0, 7, 3, 0, 0, 0, ENTER.
Upon the actuation of the ENTER button, the time is set to
7:30 AM. As another example, set the time to 7:30 PM by
pressing 1, 9, 3, 0, 0, 0, ENTER.
To display the DATE mode, simply press the DATE button.
The date, as mentioned before, is displayed in one of two for-
mats. The formats are the American date format and the Inter-
national date format. These formats are depicted in paragraph
2.5.2 step 6. The formats are selected exclusively by front
panel program 1. Refer to paragraph 2.6 for complete details
on the front panel programs.
1. Press DATE. (Selects the date mode for display and turns
on the DATE LED.)
2. Press the DATA buttons (O-9) that correspond to the
desired date. For example, set the date to August 18th for
the American date format by pressing:
A. PRGM, 1. (Selects front panel Program 1 for display.)
9. 0, ENTER. (Selects the American date format.)
C. 0, 8, 1,8, ENTER. (Enters 08.18 for the date August 18.)
Another example, set the date to August 18th for the Interna-
tional date format by pressing:
1. PRGM, 1. (Selects front panel Program 1 for display.)
2. 1, ENTER. (Selects the International date format.)
3. 1, 8, 0, 8, ENTER. (Enters 18.08 for the date August 18.)
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