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Configure GPIB-232CV-A to Communicate with Serial Instrument

Hardware: GPIB>>External Controllers/Convertors>>GPIB-232CV-A

Problem:
When I setup my GPIB-232CV-A to communicate with my serial instrument I get timeout errors (such as EABO(6)). How do I configure it properly?

Solution:
There are three steps in configuring your GPIB-232CV-A:
  1. Make sure that you have a null modem/crossover cable. A null modem cable is a cable that crosses the transmit and receive lines. For more information on the different types of cables, see the link for the KnowledgeBase below titled "What is the Difference Between Null Modem and Straight Through Serial Cables?"

  2. Disconnect your serial instrument from the null modem cable (if it's connected) and perform a loopback test. A loopback test ensures that communication with the serial port of the GPIB-232CV-A is working (see step iv below).
    1. Set the dip switches on the GPIB side of the GPIB-232CV-A to the primary address that you want to use (GPIB Address). For proper functionality, the primary address of the GPIB-232CV-A cannot be the same as the interface number of the GPIB controller. The different configurations can be found starting on page 2-2 of the GPIB-232CV-A User Manual, linked below (Note that Figures 2-1 and 2-2 are incorrect. The DIP switches should be opposite to how they are depicted in Figure 2-1 for the GPIB side. Figure 2-2, depicting the serial side, is correct but the On 'arrow' is pointing in the wrong direction).
    2. Set the Config switches to off.
    3. Set the Mode switch to D Mode, which is off. D Mode indicates that you are using GPIB to communicate with a serial instrument. Configure the DIP switches on the serial side of the GPIB-232CV-A according to Figure 2-2 of the manual.
    4. Take a wire and connect pins 2 and 3 on your serial cable, which are the pins for TXD and RXD (we will then read precisely what we write in the same port.
    5. Open Measurement and Automation Explorer.
    6. Expand My System and Devices and Interfaces.
    7. Right click on your GPIB device and select Scan for Instruments.
    8. Right click on the instrument and select Communicate with Instrument.
    9. Click on Configure EOS (for End Of String character).
    10. Check Terminate Read on EOS and select the decimal equivalent for the EOS byte that your serial device requires (for the loopback test this is decimal value 13 for \r). An ASCII table is shown below for reference.
    11. Type *IDN?\r in Send String. If your instrument requires a different EOS than the carriage return then replace \r with the required string. Since you are doing a loopback test you should read *IDN? back.

  3. Attach your instrument to the serial cable.
    1. Turn the GPIB-232CV-A off and back on.
    2. Check to see that Busy light is not on.
    3. Set the baud rate to be the same for your instrument and the GPIB 232CV-A.
    4. Redo v-xi in Step 2. Instead of getting *IDN?, you should get the ID of your instrument.



Related Links:
KnowledgeBase 3GLDMSIT: What is the Difference Between Null Modem and Straight Through Serial Cables?
Product Manuals: GPIB-232CV-A User Manual (November 1999)
KnowledgeBase 2LL9REAL: ON/OFF Direction for DIP Switches on the GPIB-232CV-A

Attachments:


ASCII Table.JPG

Report Date: 01/07/2005
Last Updated: 05/09/2008
Document ID: 3H69A7BP

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