Precautions - Omron NT20S Operation Manual

RS-232C Interface Unit Communications
6-1-2

Precautions

Command Length
Interval Between Transmitted Commands
Controlling PT Status with Operating Commands
Coordinate Specification with the Terminal Commands
Error display
Some important points to consider when using commands are listed below.
If a mistake during command specification results in a command being too long,
the correct length of the command is executed and the remainder is ignored.
A timeout error results if a mistake during command specification results in a com-
mand being too short.
As a small number of bytes is transmitted by the Host, the interval between trans-
missions should not exceed 5 seconds if a command is divided up for transmis-
sion. A timeout error occurs if the interval between transmissions exceeds 5 sec-
onds.
When commands are sent too frequently, a buffer overflow error may occur if the
NT20S cannot keep up with the command processing.
In order to prevent buffer overflow, use flow control.
Control of the NT20S status by the operating commands is restricted by the
NT20S memory switch settings as listed below.
Operating command
Buzzer control command [ESC] T
The entire command is ignored if any point specified at coordinates X, Y with the
Terminal commands lies outside the screen.
If the "automatic reset after communication" memory switch of the NT20S is set to
ON, no message is displayed when a communication error occurs.
However, time-out errors are displayed.
Restriction from memory switch
setting
Effective when "buzzer turned on"
Section 6-1
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