DCS system control points for the reactor mixing motor
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Recently, the company hired a foreign design firm to create process diagrams for the production of active pharmaceutical ingredients. On the agitator motors in these process diagrams, there are several control points within the DCS system: 1. SI (agitator motor speed indication), 2. SIC (agitator motor speed indication controller), 3. XA (agitator motor fault contact), 4. XC (agitator motor start/stop contact), 5. * (agitator motor running indication). I would like to ask experts: what instruments need to be installed on the agitator motors in order to control these control points using the DCS system? Or are other accessories needed to operate it?
This post was last edited by liuei on 2010-3-4 at 11:47: 1 (indication of the mixing motor’s speed), the signal is taken from tachometer 2; (controller for displaying the mixing motor’s speed), a PID loop is configured on the DCS 3; (notification in case of mixing motor failure), the signal can be obtained from the frequency converter 4; (control for starting/stopping the mixing motor), from the DCS to the frequency converter 5; (indication of the mixing motor’s operation status), the signal is taken from the frequency converter. A speed controller needs to be installed (usually a frequency converter), and a tachometer is used as well (usually an encoder). DCS signals: AI for speed indication, AO for speed control, DI for operation/failure indication, DO for start/stop control
If the mixer is controlled via frequency conversion, the motor speed can be obtained directly from the 4–20 mA analog output of the frequency converter, eliminating the need for a tachometer.
The inverter has an analog output of 4–20 mA, which is used to measure the output frequency of the inverter; this can indirectly reflect the motor’s speed. However, due to slip in the motor, the measurement may not be entirely accurate. This method can be used when high precision in speed measurement is not required! If it is connected to a synchronous machine, its speed being synchronized with the frequency, it can accurately reflect the motor speed indirectly!
The inverter has an analog output of 4–20 mA, which is used to measure the output frequency of the inverter; this can indirectly reflect the motor’s speed. However, due to slip in the motor, the measurement may not be entirely accurate. This method can be used when high precision in speed measurement is not required! If it is connected to a synchronous machine, its speed being synchronized with the frequency, it can accurately reflect the motor speed indirectly! liuei posted on 2010-3-5 09:57 [/quotl] In what industries is this situation where separate speed measurement is required, as mentioned by the person above, generally used? Generally, our signals are obtained from the VSD. In addition to those mentioned above, we also require a Local/Remote signal, which is mainly used for interlocking purposes to ensure that our control signals can be sent to the motor
I’ve never seen a motor used for mixing that requires speed control; is this commonly used in the pharmaceutical industry? What are the benefits? Is it related to the material level in the tank? But it seems like it can save some energy, right?……
His design includes a speed control adjustment. By directly using the inverter’s output value for conversion, the result is more stable, and no adjustments are required. The meaning of PID control is lost. It is recommended to install a speed measurement device.