What does it mean to be connected like this, with TI and TT?
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This is the P&ID of the pyrolyzer. Why aren’t the elements marked in red connected directly? What does it mean that they meet together on the pipeline before separating again?
TI refers to the on-site thermometer, while TT stands for temperature transmitter. TI is used to measure temperature, whereas TT converts temperature signals into other formats, such as 4-20mA signals. I wonder if there are other places where 4-20mA signals derived from temperature are needed
The signal lines leading to the control room are shown in dashed lines
TG is the field thermometer, TI is the on-site display, and TT is the transmitter
TI simply stands for temperature indication; whether it’s at the site or in the control room depends on that horizontal line
This post was last edited by qugd on 2021-12-30 at 12:50. It refers to field instruments with transmission functions or transmitters with display functions, similar to TIT. Due to the high temperatures in the pyrolysis furnace, the transmitter may not be able to withstand such high temperatures; therefore, it is installed at a distance from the furnace. The transmitter can have a display unit, but the temperature sensor is installed in the high-temperature area of the pyrolysis furnace. This temperature element should be a high-temperature thermocouple.
The vertical pipelines are process pipelines, and the intersection points are the temperature installation locations. TT indicates the field temperature; it is a primary instrument equipped with a temperature transmitter. Those marked with squares represent the function of the system node TI as displayed in the SIS. The lines with small circles represent the signals sent to the SIS, which are then compared with THA1121; when the value is greater, the logical judgment results in a value of 1, which is sent to the TY logic processing block
Take a look at what he writes in note 4.8