Keithley 7001 User Manual

Front Panel Operation
4-45
In the low state (0V), the output transistor sinks current
through the external device. In the high state, the out-
put transistor is off (transistor switch is open). This in-
terrupts current flow through the external device. Most
applications use active-low (ON=0V) LOGIC-SENSE.
Use the LOGIC-SENSE menu to check or change the
sense of each digital output line (refer to OUTPUT-PO-
LARITY in paragraph 4.6.3).
Outputs used as logic inputs
To use the digital outputs as logic inputs to active TTL,
Low-power TTL, or CMOS inputs:
1. Connect the Model 7001 digital outputs to the logic
inputs.
2. Connect the digital grounds.
3. Using the OUTPUT-STATUS menu, check the set-
ting of the Model 7001 output lines. The OUTPUT-
STATUS value for each output used should be ON.
4. Using the OUTPUT-POLARITY menu, check the
logic-sense setting of the Model 7001 output lines
(TTL1 through TTL4). Make sure the correct LOGIC-
SENSE value is selected for each output line. The
LOGIC-SENSE value varies according to the type of
TTL, Low-power TTL, or CMOS inputs used (AC-
TIVE-HIGH or ACTIVE-LOW).
When low (0V), the output sink can drive at least 10
standard TTL inputs. When high (+5V), the 10kΩ pull-
up resistor will source >100µA while remaining at
>3.75V output (a reliable logic high).
CAUTION
Do not apply more than 100mA max-
imum current or exceed +30V maxi-
mum voltage on pin 3 of J1007 (the
digital I/O port). Applying current or
voltage exceeding these limits may
damage the instrument.
An externally powered relay connected to the digital
output port is shown in Figure 4-10. Other externally
powered devices can be similarly connected by re-
placing the relay with the device. When using the
Model 7001’s collector outputs to turn on externally
powered devices, set the correspinding digital output
line parameters as follows (set through the MAIN
MENU > DIGITAL-I/O > OUTPUT-STATUS and
OUTPUT-POLARITY menus):
OUTPUT-STATUS=ON
TTLX LOGIC-SENSE=ACTIVE-LOW
NOTE
The X in TTLX represents the digital
output line number (TTL1 through
TTL4). This parameter is set through
the OUTPUT-POLARITY menu by se-
lecting the desired digital output line
number and pressing Enter.
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Keithley 7001 Specifications

General

Brand	Keithley
Model	7001
Category	Switch
Language	English