How to send an ASCII break from Com port?

[seimac]

Hi,

I am wondering if it is possible to send an ASCII break from the T100MD888+ PLC?  I have equipment that requires an ASCII break to be issued before communications can start.

[support]

What is the ASCII code for the "ASCII Break" that you mentioned? You can use the OUTCOMM command to send any binary data from 0 to 255. However, it is assumed that the data are transmitted using the NRZ format of 1 start bit, 8 data bit, 1 stop bit and no parity.

[seimac]

An ASCII break is not a character, but rather a level on the transmit line.  The break is a SPACE (logic 0) on the transmit line for a set duration, longer than the time for a character.  In my case, I need to send a break of 100 mS duration to 'wake-up' my piece of equipment so I can send other commands to it over the serial line.  Sending a NULL (0x00) won't work, as this is a valid ASCII character.

[support]

Unfortunately the command set does not support the RS232 break signal that you mentioned. You will probably need to use a relay to switch out the RS232 transmit line and connect it to a +5V or higher when you want to send that 100ms "break" signal.