Need help programming the KS 3988 CAMAC Controller driver to write/read the threshold on LeCroy 3420 CFD

[Kunal]

I am trying to use a Kinetic Systems 3988 GPIB Crate Controller to write / read the threshold of LeCroy 3420 Constant Fraction Discriminator.
I have downloaded the ks 3988 driver from ni.com, and I need help trying to use it. I've built a simple application which uses 4 modules from the driver. The design is as follows:
[Open.vi]-->[Write General.vi]-->[Read General.vi]-->[Close.vi]
From reading the LeCroy Manual, the CAMAC commands to write the channel Threshold on CAMAC W1 - W8 is F(16).A(0-15) and to read the channel Threshold on Camac R1 - R8 is F(0).A(0-15). So I set the (N,F,A) parameters for the Write General.vi and Read General.vi to (7,16,0) and
(7,0,0), where N = 7, which is the slot in which the CFD module is infixed.
Also, I have a input data parameter for the General Write.vi, but it is set to 0(default value) because I'm not sure as to what data is to be passed.
Other parameters are GPIB Addresse : 16, Points to read 1, data words 8 bits, Transfer Mode : Single, Status byte : Disabled.
After running this VI, I get an error which follows:
Error -1073807339 occurred at VISA Read in KS3988 Read Single.vi->KS3988 Read General.vi->test1.vi. (I call my VI, test1.vi)

Possible reasons:

VISA: (Hex 0xBFFF0015) Timeout expired before operation completed.

Also, I tried using the MAX(Measurement and Automation Explorer) to see if the CAMAC Controller responds to the *IDN? string, and it doesn't respond, but it does detect an instrument at addr. 16. I, also, used ibic interface and wrote the same string using ibwrt, it returned 'count 5' indicating that the *IDN? string had been written, but when I typed
ibrd, it gave me a timeout error.
I would be real thankful if someone can give me a detailed explaination on how to go about solving this problem.
Thanks.

[Ray K]

Hello Kunal,
You are trying to read from the ks3988 when it does not a have a message. This could mean a variety of things:

- You are not sending an valid command
- The command you are sending is not supposed to recieve a response
- You are not sending a termination character, which may be required. Some instruments,especially old ones require a termination character such as a linefeed (\n), carriage return(\r), or both.

Check your instruments' user manual to make sure everything mentioned above is correct. You mentioned that the MAX detects an instrument at address 16. The way the scan for instruments works is that it checks for listeners on the GPIB bus then sends the *IDN? query to all instruments. If MAX shows a description of the instrument then the i
nstrument responded to the *IDN? query. To see the description, click on the instrument and look at what is listed for Identification in the window to the right.

Regards,
Ray K
NI Applications Engineer

[Max Roach]

Hi, I have exactly the same problem.
Could you tell me what you have done to resolve this timeout problem?
Max Roach

[MXI Master]

Max,
Are you having the exact same problem with the same instrument? The troubleshooting Ray suggested is the best course of action. I would try those things, and if you continue to have problems post back with details of what you have tried.

Since this forum is 5 years old, there is not a high chance the original posters will be able to help you, but I will do my best to help you out.

[maulik710]

i have some problem in GPIB extender when i am reading data from LecRoy2249 ADC that time m not getting proper data in Channel Using GPIB Extender 140A (NI). i need help for reading actually ADC 2249 11bits and GPIB-140A is 8 bit TX RX using fiber optics... help me..