Issues with the shaft vibration signals of the compressor?
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The last edit to this post was made by lflsedin on 2015-12-14 at 13:56. I want to know what kind of signal represents shaft vibration in a compressor, and how it communicates with the DCS – through hard wiring or soft points?
Shaft line instruments can be integrated with Bentley’s 3500 system. Use hardwiring
Many are converted to current or voltage via on-site controllers and then transmitted to the DCS through cables
Should it be connected to the DCS through Bentley’s testing system?
First, the shaft signals such as phase, displacement, and vibration from the field are introduced into the Bentley system via hard wiring; after being processed by the Bentley system, they are then transmitted to the control system through communication
First, it passes through probe detection to obtain the corresponding inductive reactance; after that, through processes such as detection, transmission, and conversion by preamplifiers and amplifiers, it is transformed into a standard signal of 4–20 mA or 1–5 V, which is then sent to a DCS or PLC.
Generally, it involves using a framework like BENTL 3500; the modules are capable of converting vibration signals into 4-20mA signals. Of course, this framework also supports communication with DCS systems via the Modbus protocol. Also, to save money, some units have vibration displacement transmitters installed on-site to convert 4-20Ma signals to DCS signals
It’s actually very simple. You can search for the functions of a four-in-one vibration probe to find out. The four-in-one version measures the vibrations on the X/Y/Z axes as well as axis-related issues; it can detect these using a single probe, and the data is converted into standard signals that can be directly accepted by DCS.
Equipped with vibration sensors, hardwired connection, AI, 4~20mA
On-site, in addition to vibration detectors, there is also a wired connection to a signal converter, which transmits the signal via 4-20mA to the DCS. The same principle is applied to detect shaft displacement in the hydrogen feed pump and shaft settlement in compressors; however, it is difficult to adjust the displacement detection settings
The shaft vibration is a voltage signal of around -10V coming from the sensor; after passing through secondary instruments such as 3500, it is converted into a 4-20mA signal that is sent to the DCS system