Millisecond Forums

sending signals through a serial port

https://forums.millisecond.com/Topic7010.aspx

By m.hengstler - 11/17/2011

Hi guys!



Okay, so here's the story...



We have a device that can be connected to a pc via an usb-cable. The connection is established via COM5 (which is visible in the device & settings section of windows). The device can only read the following 'signals': 0, 1, & 2.


We know what the settings are for the device (baudrates = 38400, databits = 8, parity = none, stopbits = 1, & control = hardware), and those are set to what they are supposed to be via windows.


Now, if we want to send a signal (either 0, 1, or 2) via Inquisit, the machine doesn't respond (only when we actually close the serial port monitor, which in itself is quite strange as well...). Also when we program a test-script, the machine doesn't respond to the signal we send.


Might it be due to the fact that the item of a port element is required to have 8 digits? Because our device only reacts to 1 digit items. If so, are there any workarounds for this problem? If not, did we do anything wrong in the first place?



Thanks in advance!


Maikel

By Dave - 11/17/2011

Now, if we want to send a signal (either 0, 1, or 2) via Inquisit, the machine doesn't respond (only when we actually close the serial port monitor, which in itself is quite strange as well...). Also when we program a test-script, the machine doesn't respond to the signal we send.


Not sure what you actually mean to say here, but if you cannot trigger the device via Inquisit's Serial Port Monitor (Tools -> Serial Port Monitor...), you probably won't be able to trigger it via syntax either. While there are conceptual similarities, the USB standard is substantially different from the RS-232 serial communication standard.


Might it be due to the fact that the item of a port element is required to have 8 digits?


<port> elements in Inquisit do *not* send 8 digit *numbers* or other arbitrary strings. They only send 8-bit *binary* values, your device might or might not be able to make sense of. FWIW, of course


------------------------
Decimal   ->    Binary
Base 10   ->    Base 2
------------------------
0         ->    00000000
1         ->    00000001
2         ->    00000010
------------------------


(bit order might have to be reversed). If your device expects ASCII data, though, I think you're out of luck.


Regards,


~Dave