Before You Start

Here are some things you should know about the display and keypad (Figure 3‑1).

Cursor Control Keys

The cursor control keys (▲, ▼, ◄, ►, pgup, pgdn, home, and end) appear on either side of the front panel. The left group does the same thing as the right group, and it doesn’t matter which you use. Similarly, there are two enter keys and two labels keys.

Function Keys

Keys labeled f1 through f5 below the display are called function keys, and often have labels associated with them on the bottom line(s) of the display. When there are multiple definitions for these keys, the labels key can be used to cycle through them (and shift + labels to go backwards). Sometimes, the labels remain hidden even though function keys are defined and active; pressing labels will make the labels temporarily appear.


The display has independent text (8 lines, 40 characters per line) and graphics (64 dots high, 240 dots wide) modes. In this tour we will use both.

You can adjust the contrast by pressing ctrl + shift + ▲ and ctrl + shift + ▼. Also, if it is so equipped, you can toggle the display backlight on and off by pressing ctrl + home. All the hot keys are listed in Table 3‑1.

Figure 3‑1. The LI-6400 keypad. The cursor control keys, labels, and enter are paired to facilitate access with either hand.
Table 3‑1. Hot key combinations - valid any time.
Press... To Do...
ctrl shift Darken display contrast
ctrl shift Lighten display contrast
ctrl shift home Toggles display backlight (if installed).
ctrl shift Turn graphics mode on. If already on, turns text mode off.
ctrl shift Turn text mode on. If already on, turns graphics mode off.
ctrl escape Abort the current application.
ctrl shift escape Reboot.
ctrl shift end (XT Only) Unmounts compact flash card (if inserted).
[ Enter/Exit Diagnostics Mode
] Enter/Exit Graphics Mode
a...z (Text) Selects display line.
(Diagnostics) Selects display screen (a - i).
(Graphics) Selects graphics screen (a - h)
0...9 (Text) Selects display line.
(Diagnostics) Selects display screen (a - i).
(Graphics) Selects graphics screen (a - h)
(Text) Implement a Display Group key.
ctrl home
ctrl end
ctrl pgup
ctrl pgdn
(Text) Define a Display Group key.
▲▼ (Text) Select new display line
(Graphics) Select new display screen
◄► (Text) Select new display line
(Graphics) Select new display screen
(Graphics) Change chart selection
ctrl z Toggle warning messages on/off.
ctrl s (Graphics) Store current graphics display to /User/Images/RTG_yyyy-mm-dd_hh-mm-ss.
(Text & Diagnostics) Store a system snapshot
(variables, values, settings, etc.) to a text file names /User/Snapshot_yyyy-mm-dd_hh-mm-ss.