Application ranges of temperature transmitters and thermal resistors
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In factories these days, when measuring temperature, thermistors are used in some places while temperature transmitters are used in others. But it’s not clear what is used in those places? I have a question: in which cases is temperature variation necessary, and in which cases is it not? Are there any clear requirements regarding this in the standards? Thank you!
The type of transmission signal is a formula agreed upon jointly by the design institute and the owner. In other words, if the manufacturer prefers standard signal types, then standard models should be used. After all, everyone has their own preferences; there’s no need to get too stuck on it – it’s sufficient for both parties to reach an agreement. :)
A temperature transmitter is used to convert thermoresistive signals or thermocouple signals into standard current signals. Typical temperature transmitters have a configuration interface, which allows for configuring parameters such as the signals connected to the temperature sensor, its measurement range, and the status of any disconnections. So the card modules they use are different. There are no rules specifying under what circumstances temperature variation must be used. However, generally, intrinsically safe types require a temperature sensor to be used.
The output signals of the two products are different, depending on the temperature sensing module used by the manufacturer.
Temperature sensors output standard current signals and are primarily used in systems that require integration with DCS and PLC systems, whereas thermal resistors are mainly used in instruments for single temperature display and control.
There is no unified standard; it depends on the communication between the owner and the design firm
Is temperature variation measured more accurately during long-distance transmission?
Temperature transmitters output standard current signals and are primarily used in systems that require integration with DCS and PLC systems, whereas thermal resistors are mainly used in single temperature display and control instruments. It’s the type that is installed on-site.
This post was last edited by HEJIYUER on 2015-12-8 at 23:50. The thermal resistance is directly fed into the card, and it seems there is no redundant temperature card, which is a flaw for circuit control & SIS. There are always disadvantages to using temperature transmitters in the field (due to environmental temperatures and such), but they are still widely used; it depends on the practices of the factory. It is best to place the heat resistors/thermocouples at multiple points in the reactor inside the cabinet, and then use guide rails to convert temperature changes. In one of the boxes on site, there are 7/8 temperature sensors – quite a lot. It’s possible that they are separate units; there’s also an additional wiring box, which means one more point where failures can occur. @jiaguoyun
It depends on the scale of your factory. If there are many thermoresistors, it is recommended to use a thermoresistor input card in the control system; otherwise, a combination of thermoresistors and temperature sensors is advised, as this helps reduce the investment cost of your system.
Temperature transmitters are generally temperature instruments that allow for both local reading and remote transmission. However, its usage is limited; integrated temperature transmitters are not suitable for use in situations where the ambient temperature at the measurement point is above 60 degrees. Furthermore, when selecting temperature instruments for skid-mounted equipment, remote-transmission temperature instruments are generally used, which are temperature transmitters. This is because the skid manufacturers cannot get in touch with the DCS manufacturers, so it is necessary to convert the signals into standard electrical signals on-site to facilitate the design of the mounting components.