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| 3/19/2015 3:52 AM | |
Joined: 3/28/2010 Last visit: 12/7/2023 Posts: 987 Rating:
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1) Yes, RTD flying lead wires connect to TH100 transmitter input. 2) I suspect that LC cable length is the distance between temp sensor and transmitter, but I don't have a spec sheet handy. No, the 100m distance limit is typically the limit of the distance between an RTD and temperature transmitter, although I prefer much shorter distances. The maximum cable length for 2 copper wires from the TH100 to the analog input signal (and a DC power supply) module is about 2Km (2,000m) for a 24Vdc power supply. That's why people use 4-20mA, it goes 'forever' and is very noise resistant (whereas RTD signals are weak and prone to noise pickup). 3) No, you don't want a 2 wire RTD. Never use 2 wire RTDs. 2 wire RTDs will ALWAYS have a positive offset error due to the resistance of the copper wire connecting the RTD to the temp transmitter. A 3 wire RTD eliminates the error for all practical purposes. Buy a 3 wire RTD and use all three wires. All three wires must be the same length and gauge (thickness). An RTD signal cannot be paralleled to two different receivers, like a PLC analog input and a digital indicator. An RTD can only go to one receiver. If you need the same temperature reading in two different receivers you need a 'dual element' RTD, which is a 2xPt100, two RTD elements in the same sheath. One RTD element wires to one receiver (transmitter), the other RTD element wires to the other receiver (recorder) 4) The transition is the section between the solid metal sheath and the extension wire. Sometimes there's only heat shrink tubing, sometimes a strain-relief spring http://www.omega.com/temperature/pdf/pr-11.pdf Most times there is 'potting' resin seal around the wires and to keep the MgO inside the sheath and water outside of the sheath. You don't want water to get inside the sheath. Water will short circuit the excitation current and produce bad temperature readings. You need to find a local RTD vendor and have them show you the various styles of RTDs. 5) element. An element is a RTD sensor. Two RTD elements in one sheath is two RTD sensors in one sheath. |
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