Multivariable transmitter
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Can a multivariable transmitter output three 4-20mA signals for instantaneous flow, pressure, and temperature simultaneously?
I’m not sure if you’re referring to a multi-parameter transmitter; if so, this one is not capable of outputting multiple variables. Instead, parameters such as temperature are input into the transmitter, which then uses compensation to calculate the flow rate
Does a multivariable transmitter refer to the compensation parameters such as temperature and pressure that are read out when using bus communication? Typical instruments are designed for single measurements, namely of pressure signals. The sensor may include a temperature sensing unit that allows for the measurement of the temperature inside the diaphragm, thereby enabling volume compensation for the pressure-transmitting silicone oil. However, it is not recommended to use such parameters for control; they can be used as a reference value for the manufacturing process.
Since the original poster mentioned flow rate, temperature, and pressure, it must be a flow meter. Normally, an AO output point consists of just one pair; if multi-variable output is required, it can probably be achieved through communication protocols such as Hart.
Rosemount has one that can do it. The instrument itself has the capabilities to measure pressure simultaneously, calculate flow rate, and monitor temperature. However, the instrument itself can only have one output channel. If multiple channels are desired, an additional device for signal distribution across multiple channels is needed
A multivariable transmitter integrates temperature, pressure, and flow measurement sensors, and performs compensation calculations to display the flow rate on-site. The current can only output an instantaneous flow rate of 4-20mA; to transmit data such as temperature, pressure, instantaneous values, and cumulative values, RS485 communication is generally used
The Rosemount 3095 gauge will work; however, a demodulator needs to be installed inside the cabinet. The signals are sent back to the demodulator via two cables, and after decoding, the signals are separated into three distinct values: temperature, pressure, and flow rate.