Keithley 194 Instruction Manual page 55

OPERATION
2. Select a random buffer location by keying in a value with
the data entry keys and then pressing ENTER. For ex-
ample to view the 56th location, press: 5, 6, ENTER. The
data at that location, along with the buffer location will
then be displayed. For example, the display might show:
16.17 56 1
3. Use the Uprange and Downrange keys to sequentially
increment and decrement buffer locations. Note that the
buttons will autorepeat after being held down briefly.
4. Press the RECALL key to return to the normal operating
mode.
3.9 DUAL CHANNEL OPERATION
When the optional Model 1944 A/D Converter Module is
installed in the CARD 2 location, the Model 194 is
equipped with two identical channels that operate virtually
independently of one another. Aside from sharing the
display and control buttons, each channel can be in-
dependently programmed for various operating modes.
The following paragraphs describe dual-channel operation
of the Model 194.
3.9.1 Channel 2 Connections
As shown in Figure 3-5, the connections for the CARD 2
module are identical to those for CARD 1. The purpose
of each connector is briefly described below. The paragraph
where more detailed information may be found is also
indicated
Figure 3-5. Rear Panel
Showing Channel 2 Installed
VOLTAGE INPUT-All analog input signals are applied to
this isolated BNC connector (paragraph 2.5).
CAUTION
The maximum input voltage is 250V peak, 2 x
10' V*Hz. The unit mav be damaoed if this value
is exceeded.
WARNING
The maximum common-mode voltage is 30V.
Exceeding this value may create a shock
hazard.
REAL TIME OUTPUT-Provides binary data from the A/D
converter at the sampling rate (paragraph 3.20).
TRIGGER OUT-Provides an output pulse to trigger other
instrumentation when channel 2 is triggered for a measure-
ment sequence (paragraph 3.6).
TRIGGER IN--Allows channel 2 to be triggered from an
external sowce. This mode is available only when properly
programmed with the SOURCE key (paragraph 3.6).
CAUTION
Digital common is internally connected to
chassis ground and cannot be floated.
NOTE
Shielded cable should be used for all input and
output connections to minimize the possibility of
EM1 radiation.
3.9.2 Channel Selection
The channel to be accessed is selected by using the CHAN-
NEL button.
CHANNEL BUTTON
CHANNEL
I
3-16