ruby serialport flow control is not working

Asked Jun 19 '13 at 14:23

Active Jun 20 '13 at 08:00

Viewed 430 times

Im using the serialport gem which has done a good job for me so far. But now I realized the flow_control is simply not working. First I thought its a problem of my usb rs232 adapter but it isnt. I tried it with an onboard rs232 interface and it failed too. Im using the newest version of debian and ruby 1.9.3.

Im initializing the serialport like this:

sp=SerialPort.new("/dev/ttyS0")
sp.baud=300
sp.data_bits=7
sp.flow_control=SerialPort::HARD

And its initialized without any errors but when I try to send some data I dont get any answer and there is no handshaking done. Am I doing sth. wrog?

// When I send a command the device answers:

DC4 (CTRL T)  -0> IEC-0INTERPRETER (MIT ECHO)
DC2 (CTRL R)  -0> IEC-0INTERPRETER (OHNE ECHO)
DC1 (CTRL Q)  -0> MONITOR10

So data bits, stop bits and baud rate are okay but the answer seems to "ask" me to change some settings?!

edited Jun 20 '13 at 08:00

asked Jun 19 '13 at 14:23

davidb

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Try turning DTR and RTS on. – dbasnett Jun 19 '13 at 14:33
like this? `sp.dtr=1` and `sp.rts=1`? – davidb Jun 19 '13 at 14:39
I am not a ruby programmer, but from what I can tell from the documentation that looks correct. Try it and see. – dbasnett Jun 19 '13 at 14:42
I tried it but it didnt change anything – davidb Jun 19 '13 at 14:44
What kind of device are you connecting with? – dbasnett Jun 19 '13 at 14:45
A UPM60 measurement amplifier – davidb Jun 19 '13 at 14:46
If I am looking at the right device you need to set stop bits to 2 and parity to even. Get rid of the flow control. – dbasnett Jun 19 '13 at 14:52
I tried it but doesnt change anything. I already sniffed the working conversation between a really old pc using DOS and the measurement amplifier and the conversation Im rebuilding with ruby took about 30 secounds and they used hardware based flow control. – davidb Jun 19 '13 at 14:58
Could you tell the settings from your sniffing? Pins, speed, parity, stop bit? What kind of serial port on the old PC? – dbasnett Jun 19 '13 at 15:01
I added some info to the post,... The device answers but not as excepted. – davidb Jun 20 '13 at 08:01
You are going to need to understand the protocol of the device. Between the manual and the ability to sniff on the old pc you should be able to figure it out. I have neither so it will be hard for me to help. – dbasnett Jun 20 '13 at 12:33

ruby serialport flow control is not working

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