ICP DAS USA I-7521 User Manual page 39

character of the command string. If this character is not sent, COM2 will
continue to receive command characters and consider them as part of the
command string, resulting in an error.
For more information about RS-232 COM ports, refer to the Notes in Sec.
5.3.33.
b: CrLfmode=4
The factory default value for CrLfmode is 4 for all COM ports. In this mode, the
I-752N module determines the end of a command string once no characters
are received for a specified timeout interval.
For example:
Command
PC
Assume the timeout interval is 10 ms.
Command string: ":01T"
If you type the first character ':', then type the second character,'0', after 5 ms,
type the third character ,'1', after 1 second and type the fourth character ,'T',
after 3 ms
Two command string will be received by COM2, which will be ":0" and "1T",
not ":01T". So the command received is not the same as the original
command.
The timeout interval is so small that it is impossible to manually enter
individual command characters. In this situation, the command string must be
sent at one time using software. The interval between transmission of the
characters can be very small if the command string is sent using software.
c: Set the corresponding CrLfmode for all COM ports depending on the
command and response.
For example:
PC
COM2 of I-7522A
Command: ":01ABCD<CR>" sent by PC
Device response: "EFGH<CR>," when the command is "ABCD<CR>"
Situation 1:
I-7522A, COM2 CrLfmode=0, COM1 CrLfmode=4
I-7521/I-7522/I-7522A/I-7523/I-7524/I-7527 User's Manual,Ver2.5 Aug.2015
I-752N
I-7522A
COM1of I-7522A
Device
39