Instrument Control (GPIB, Serial, VISA, IVI)

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ECG OEM board communication with Labview using Instrument IO Assistant

  I'm using the Instrument IO Assistant to establish communication with my Smiths Medical ECG OEM board(RS232).  I have entered all the appropriate port settings, but when I enter a command to query and parse it times out.  For example I enter :AA 02 10 44 in the command line as the appropriate query command according to device specs, but it times out before the operation completes.  I don't have a device driver so I am just experimenting at first to make sure the devices can communicate.  Anyone have any suggestions?
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Message 1 of 11
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add cr/lf to your command to make sure it is recognized
and are you sure you need to type hex characters (is the type of string display hex or normal or /code display?
greetings from the Netherlands
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Message 2 of 11
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I tried adding cr/lf to the command, but the same error occurs .  The manufacturers specs say to use hex characters to communicate.  Is there another type of code you think I should be using?  In your experience with RS232, what do you use for communication, ie what would be a command you would use to test communication with the device?

Thanks
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Message 3 of 11
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slarkin 712,

One way to test to make sure your device is sending the correct commands is to perform a serial loopback test.  The commands are device specific thus you need to reference the device manual, which it seems you have.

A_Ryan
AES
National Instruments
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Message 4 of 11
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Thanks A_Ryan.  I performed the serial loopback test as described in the tutorial using hyperlink and it worked perfectly.  I then hooked that serial cable up to my Pulse-ox/ECG OEM board and enter the correct specs (38.4K Baud, 8 data bits, 2 stop bits, no parity, no flow control)  and tired to communicate using hypertreminal.  When I type in the terminal window nothing appears.  My serial port is working fine, I just can't communicate with my device for some reason. ???
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Message 5 of 11
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Double check the com settings and then verify you are using the correct type of serial cable. There two general types. A straight through and null modem cables. Hopefully your manual will tell you which to use but if it doesn't, try the opposite of what you have now. A straight through cable is just that. Pin 1 at one end connects to pin 1 at the other, pin 2 to pin 2, etc. A null modem cable swaps the tx and rx lins so that pin 1 would connect to pin 2 and pin 2 to pin 1.
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Dennis:

Did you mean to say pins 2 and 3, not 1 and 2?

-AK2DM

 

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"It’s the questions that drive us.”
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Message 7 of 11
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Duh. You're right, of course.
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Message 8 of 11
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The manufacturers specs are such:
Pin 2 - TX Data Out
Pin 3 - RX Data In
Pin 5 - Signal Ground
Pins 1, 4, 9 - Open Connections
Pins 6, 7, 8 - Reserved (no connections allowed)

This looks to be a straight through configuration. The board uses BCI network protocol with a 64180 processor.  I'm not sure if this is useful information, but I'm trying to figure out why this device doesn't use standard RS-232 communication with Labview.  Any ideas?
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Message 9 of 11
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Also, when using the Measurment and Automation Explorer and the VISA test panel I used the viRead option and execute and the return status gives me xBFFF0015.  Anyone know what this means?
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