08-08-2007 04:12 PM
I am trying to communicate with a Julabo Circulator using the RS232 port. I am able to communicate with the machine with Julabo’s free software and I am able to communicate with HyperTerminal in windows. I just can’t seem to get LabView (7.1) to do the same.
The settings are: 4800 Baud, even, and hardware handshake. With HyperTerminal I set the settings and I can send commands and get responses. With the LabView examples the choices are not as simple as hardware handshake, there is RTS/CTS and DTR/DSR among others. I have tried them all and have not gotten anywhere today. I have been using a port sniffer to find out what is being sent and some of it makes sense, but not all of it.
Currently I am trying to just send a command to check the ststus of the circulator. But I am convinced that I am getting messed up with the hardware handshaking. The manual says a transfer sequence consists of:
Command
Space (hex:20)
Parameter
End of file (hex:0D)
The response (data string) after an in command is always followed by a line feed (Hex:0A).
So I have entered “in_mode_05” with enter at the end, I have also entered 69 6E 5F 6D 6F 64 65 5F 30 35 0D in hex. It looks good in the port sniffer but I never get a response using any of the LabView examples. I have even tried to set the control temp that does not require a response, but it never changes on the unit.
08-08-2007 05:47 PM
08-08-2007 06:59 PM
Hey Albert,
The LV Vs HT_out.jpg shows what my port sniffer is seeing. The 1st command out_sp_00 16.00 was from HyperTerminal and it set the machine to 16c. The 2nd command was from LabView to set it to 15c, which did not work. So I started HT back up and set it to 15c and it worked. The commands look the same to me, but the LV ones did not work.
The LV Vs HT_in_mode.jpg shows the command in_mode_05 which should return a 1, which HT did and LV did not. It also show my VI settings. I attached the vi, but it is just a copy of the example in LabView 7.1.
Bryan
08-09-2007 08:06 AM
08-09-2007 10:15 AM
I tried setting up the comport yesterday in max and removed most of the vi, it did not help. Under flow control (in Max) it has Hardware (RTS/CTS) and Hardware (DTR/DSR) not just a simple hardware handshake option like HyperTerminal. Is it possible that I need to somehow use both hardware settings, RTS/CTS and DTR/DSR? Or is it always one or the other?
08-09-2007 11:28 PM
08-10-2007 02:26 AM
08-10-2007 11:33 AM
Hey Albert,
I received a response from Julabo and they actually included a small vi. It turns out that they use 7 data bits, not 8. I double checked hyperterminal this morning and it was set for 7 data bits. I have no idea how or why it was at 7, I thought it was set at 8.
Thanks for the help,
Bryan
08-11-2007 08:03 AM
05-10-2012 02:03 PM
Here is the sample program I was sent.