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serial port communication with Lakeshore ST-133 controller using LabVIEW driver for model 330 temperature controller

hello

I am doing a thermoluminescence experiment and I wanted to trigger the ST-133 controller and communicate with it using LabVIEW. I am using a labVIEW driver to control the Model - 330 temperature controller and I would like to attach the serial port communication to it. Initially I want to just send the trigger to the controller after every rise of 5K in temperature from the initial temperature of 25K to room temperature. I do not need an acknowledgement of the system. The rise in temperature will be 9.3K/min. I am using a ramping rate feature.

 

The next part is a bit tricky. I am supposed to rise the temperature 5K from say the start of 25K. When the temperature reaches 30K. It should stabilize and the serial port should send a trigger to the controller to take the spectrum using a CCD camera. Then I should get an acknowledgement saying the process was completed and then the temperature setpoint should automatically go to 35K once the acknowledgement is recieved.

 

I have the parameters for stabilizing the temperature with an overshoot of around 0.3-0.4 K which is ok. So the parameters are known and should be the same. I have attached the library file of the driver I have. Please take a look at it and let me know how to integrate the serial port communication. The main VI is named "RSGR temperature dependence new" VI. You might even need the utility driver that is also attached.

 

thanks for looking into this and it would be great if I could find a solution to this experiment.

- Sai Gopal Reddy.

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RSGR:

This is the correct driver you will need to use Serial to talk to your 330 controller. Make sure you are using this driver and if you have any questions about particular functions, look at the VI Tree.vi under the Public folder. This driver will allow you to communicate with your device through GPIB or Serial.


Tori W.

National Instruments
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I am already using GPIB communication to connect to the model 330 Temperature controller. It is working well. I used the example in the mentioned driver set to create the driver I am using. I want to have serial communication with the ST-133 controller. The manual for it is attached for reference. The ST-133 Controller only takes a TTL signal external trigger. I would like to know how to do that using the serial port. Also it would be great if I could have a two way communication with the ST-133 controller to recieve a signal too which would indicate that the ST-133 controller has finished its job and the device is ready to increase the temperature to the next step.

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RSGR:

You will need to figure out what type of commands this device can accommodate before you can
communicate with it through serial. Do you know what commands your ST-133 uses? I was not able to
find them in this user manual and searching for that controller online returned few results. In this
other article, at the bottom of page 106, I see that there is a Dynamic Link Library associated
with your device. Do you have this library?


Tori W.

National Instruments
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What would be the parameter values (Baud Rate, Stop bit , Parity bit etc.) when using serial port communication to communicate with a Princeton Instruments ST-133 controller which controls a CCD camera to produce an outpue voltage of 5 volts. What should be the serial Write input if I have to acheive this. Would using a square waveform generator work.

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RSGR:

Serial ports are meant for communication, not really for simple signals such as a waveform. If you wanted to
do this, it will be extremely difficult. You would have to line up your frequency perfectly with your serial
parameters so that the stop and start bits are interpreted as a square wave. Even then, this is not ideal and
may cause damage/errors with your device.

I think what your device would work best with is an external device that can output a TTL signal. This can
be a simple button or something like one of our DAQ devices.


Tori W.

National Instruments
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I am sorry for the confusion I created. I will try to explain the situation. I want to use the serial port to communicate with the ST-133 controller (which accepts a TTL signal with a maximum of 5V). I want to use the rising edge of this signal as an external trigger. I have a serial cable with a DB-25 pin on one side which goes to the PC and on the other side there is a BNC connector which can go into the triggering port of the controller. The equipment can be set to work on external trigger. Now how do I write a program so that we get TTL pulse of 5V as an output. I hope I was clear now.

 

I understand that the serial port has to be a DB-9 pin but I have a DB25 pin. Is there a converter I can use to connect it to the PC serial port slot.

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That's not a serial cable at all. Nor does a serial port output a TTL signal.
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Dennis is correct. If you are looking for TTL (maximum of 5 volts) then the serial port is not the thing to use. See this article:

Serial Port Voltage Levels

 

Using a serial port to trigger a TTL input could damage the equipment with the TTL input.

 

It may be possible to build a circuit that would take the information from the TX pin (pin 2 on DB-25 connector) and change it to TTL levels. I don't have a design for this at my fingertips right now, but it will be searchable on the web.

 

     Rob

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Hello

Thanks for looking into my question. I understand that the voltage levels on the serial port are not the same as a TTL signal. I wanted to know if we could have a design in LabVIEW so that we get an output of 5V and use that to trigger the instrument. Is there any other method of obtaining a TTL trigger signal from a computer using LabVIEW to send it to the instrument. I know there are converters we can use to obtain a TTL signal from the serial port but I am a student and buying equipment is not that easy and I want to know if there is any other way around it.

 

There are cables which have been designed to have a serial port connector on one side and a BNC connection on the other to hook it up to the instrument so I thought we could obtain a TTL signal using LabVIEW.

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