1256E User Manual
Racal Instruments
©
2002
Using the Front-Panel Controls 3-13
----OPERATIONS----
Slot 03: -114TTL
>Port 05: Read <
Value: 43
Now line 4 shows the states of the eight input signals of port
5, expressed as an eight-bit decimal number. By default, the
display uses decimal notation. To change the notation to
hexadecimal or binary, refer to the
Display Format
section
of this chapter, under the
Settings
heading.
6. If desired, rotate the knob in either direction to view the
states of other digital ports. Ports programmed as inputs
reflect the states of their input signals. Ports configured as
outputs show the most recent data written to them.
Enabling a Digital Port
Before using a digital port as an output, its output buffers must be
enabled. For example, suppose a Model 1260-114TTL plug-in is
installed in slot 3. To enable output port 4, proceed as follows:
1. Press the top key next to the display. Rotate the knob until
the top line reads:
>----OPERATIONS----<
2. Select line 2 (next to the top line) by pressing the second
key. The display shows line 2 as being selected:
----OPERATIONS----
>Slot 01: 1260-121A<
Channel: 00
Status: Open
3.
Rotate the knob until line 2 shows the contents of slot 3:
----OPERATIONS----
>Slot 03: -114TTL <
Port 00: Write
Value: 255
4. Press the third key to select line 3 of the display (port
number):
----OPERATIONS----
Slot 03: -114TTL
>Port 00: Write <
Value: 255
5.
Rotate the knob until line 3 shows the desired port number,
which in this example is 4, and the desired mode, which is
Enable:
----OPERATIONS----
