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Julabo Circulator RS232 Communication

Hello all,
 
 

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.

 

Bryan  

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Message 1 of 17
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Hi Brian

please post your test vi, maybe something simple is the problem

greetings from the Netherlands
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Message 2 of 17
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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

 

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Message 3 of 17
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This looks quite similar, so something is sent by LabVIEW maybe a break at port Open.

I don't have much time now but I suggest to take an even simpler example.
Or to remove all unnecessary calls like xon/xoff char to be removed.
Also the buffersize is normally OK.
The only thing you really need is the hardware handshake and that can also be defaulted in MAX (also baudrate and other settings)
please try to keep it as simple as possible ,just like HT does
greetings from the Netherlands
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Message 4 of 17
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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?

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Message 5 of 17
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Hi
DTR/DTS the hardware signals that mean my Data Terminal is Ready (powered on) and Data Terminal is Set.
While RTS (Request To Send) and CTS (Clear To Send) should be used to interrupt an already working system.

I would switch to RTS/DTS and make sure that the voltages on DTS and DTR are OK.
For these signals you have property nodes that can activate them.

Check with a volt meter the DTR/DTS lines in hyperterminal and set them with the property node.

greetings from the Netherlands
Message 6 of 17
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Hello,

Do you mean DTR/DTS or DTR/DSR? Is my computer sending out both signals? Or do I need to check on the computer side and the Julabo side? And I should be able to measure that between Pin 4(DTR) and pin 5(ground) and then Pin 6(DSR) and pin 5(ground). Then I can use the Serial Instr property node (modem line settings) to set the states of DTR/DSR....

I can't wait to get to work tomorrow to try this.
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Message 7 of 17
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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

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Message 8 of 17
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Hi Brian

Sometimes the simplest problem is overlooked, even by the  experienced  engineer.
 
greetings from the Netherlands
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Message 9 of 17
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Here is the sample program I was sent.

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