Maple Systems STEPware-100 - Manual (Page 56)

CHAPTER 6
LED and Printer Operation
Using the OIT’s LEDs
Some of the OIT models which support the STEP1 protocol have LEDs which can be
activated by control commands sent from the host controller. These LEDs can be split
into three categories:
• Function Key LEDs — located next to each function key. Each function key LED is
referenced according to the function key it is next to. For example, the LED next to
Function Key #7 is Function Key LED #7.
• Status LEDs — a row of eight LEDs. On the OIT3250 each status LED is labeled with a
number, 1 through 8. The OIT4450 and OIT5400 have a slide-in legend that lets you
customize the label for each status LED.
• System LEDs — four LEDs with predefined labels: MESSAGE, ALARM, RUN, and
PRINT. The labels define the function of each system LED when the OIT is operating with
one of Maple Systems’ PLC (programmable logic controller) protocols included in the
OITware-200 configuration software. Since the STEP1 protocol allows you to use these
LEDs for any purpose, the labels assigned to each system LED do not necessarily indicate
their function.
None of these LEDs are used by the OIT. Therefore, you can define the function of each
LED. The host controller causes the LEDs to turn on, turn off, or blink using the
following control commands:
• Function Key LED control command (
ESC
X functionLED# mode terminator)
• Status LED control command (
ESC
Y statusLED# mode terminator)
• System LED control command (
ESC
Z systemLED# mode terminator).
Refer to Appendix A: Control Commands for more information on the control
commands.
Using a Serial Printer
Some of the OIT models which support the STEP1 protocol have a second serial port that
can be used to attach a serial printer. When a serial printer is attached to the OIT, the host
controller can send the contents of the OIT’s display or a string of ASCII characters, both
printable and control, to the printer using the following control commands:
• Print Screen control command (
ESC
O terminator)
• Print Text control command (
ESC
P text terminator).
Refer to Appendix A: Control Commands for more information.
The attached serial printer will treat certain ASCII control characters as formatting
requests (refer to the printer’s manual). By embedding these ASCII control characters
into the text sent with the Print Text control command, you can format the printed output.
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