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User selectable Thermocouple type??

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I have many applications where the Control that is programmed has been made for a particular industry tast, but I will not know what specific sensors will be used to make the final application. The most common example of this is a simple thermocouple. In most instance the thermocouple used will be either a T, J, or K type, but I do not know what it will be till just before sale (or told once the unit is allready in the field and the customer picked some other type than what I set up in the hardware configuration. Wile I know that this should not happen it does and I would like to not have to send files out to be downloaded by the custoemr to make field alterations for this kind of change. In the specific projects I have in mind, they are all Vision series controllers and are most commonly either a V570, V350, V530, and V1040. I am not looking for a user to be able to select between thermcouple, 4-20ma, and 0-10Vdc (since these changes would required physical jumper changes). I am only looking to give options for different thermocouples types.

Is there a way to make the thermocouple type selectable on the touch screen screen? Or, do I need to pick up the raw thermocouple data and scale this via ladder programming and use the converted engineering value calculations for all further operations and display images?



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  • 1 month later...


There is no option to change the hardware configuration via touch screen or ladder.

Please send mail with the request to support@unitronics.com for evaluating your request.

This is something that definitely should be selectable at runtime. I run into the same problem. Some customers like K t/cs and others like J's. It is silly to have to maintain multiple program versions that would be otherwise identical just to select the Type of TC being used.

My guess is the reason it was not done this way is because the program only compiles with the curve tables that are selected at design time, as opposed to downloading all the curve tables even if you don't need them. Instead, maybe we should be able to select which curve tables we want to make available.

Even making 4-20mA and 0-10v should not be an issue. Yes, it requires setting jumpers. But so what. Any half way decent electrician could handle setting jumpers on a new unit.

Also keep in mind, I can buy a dedicated heat controller for next to nothing, and It has been over a decade since I have seen one that does not allow you to configure the T/C type used. It's not cutting technology. The price and capability of the unitronics PLC's makes them well suited to creating Universal Multi-Zone Temp/Process controllers, but many of the decisions that were made in software (ie. inability to select type of T/C at runtime, inability to select parameters like the # of stages in Auto Tune, Inability to select output type mA/V) all detract from it.

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As an idea, when we are selecting the feedback type in the declaration window, maybe we could select RAW, and then R&D could develop a function block. This FB would allow you to select any of the feedback options available. It would also allow you to select during runtime between using F or C. This solves a couple conundrums. 1) It keeps everything backwards compatible, 2) It gives users like those of us in this thread the increased flexibility that we need, and 3) it also overcomes the problem of not wantiing all those curve tables downloaded all the time since it would only do so if you used that function block.

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