1. What are the differences between HMI and SCADA? In large industrial structures, it is impractical or even impossible to control the individual parts of the system because, in most installations, the parts are often located very far from each other. Thus the need arises to monitor and control them with SCADA and HMI. The main difference between SCADA and HMI is their scope. HMI is actually just a part of the larger SCADA system. Without SCADA, the HMI would be pretty much useless. SCADA” stands for “Supervisory Control and Data Acquisition,” which is an integrated system that is used to control and monitor the workings of the individual parts of the plant. The SCADA often controls pumps, fans, and other machinery along with their other characteristics. The controlling mechanisms are electronic circuits known as programmable logic circuits or PLCs. The PLC controls the machine as well as polls the sensors for data. The data is then sent to the control room. In the control room, the operator needs to make sense of the data as well as issue commands like turning the machines on or off.
This is where the HMI, or Human Machine Interface, comes in. The HMI is usually a graphical layout of the entire system with gauges, lights, and controls situated in the corresponding locations of the machines. The gauges show the normal range of operation as well as the abnormal range so that the operator knows if the equipment is within the accepted operating range. The lights may indicate if the machine is working or not, as well as the occurrence of faults. The controls send the instructions to the PLC, which in turn control the machine.
SCADA is a complete control system while the HMI is what the human operator works with it. 2. Give at least 3 advantages of HMI. Alarms (Real Time / Historical) Viewing alarms will help the operator to locate and react faster to any malfunction of any anomalies. Some of the alarms could be of preventive type, for example to create a warning alarm on a hydraulic tank oil level before the oil level really reaches a critical point. Recipe Manager Simple and complex recipe could be controlled with HMI. This is very useful and very effective way to execute recipes. Messaging This is a very interesting functionality.
You can message, page or fax someone when a certain event happens. For example let say the oil level in the hydraulic tank has reaching a low level. Then low oil level will be triggered and it will page the person in charge to fill up the tank. 3. Give at least 2 disadvantages of HMI. HMI – it is more specific for a particular machine, and difficult or impossible to adapt to more general applications. (Compared to SCADA) -And it also more expensive. 4. In my work experience from the DOLE South Cotabato as a trainee (OJT) there is an operation that had used the advance technology of HMI.
In area of Juice Line where this area its fill a syrup from the juice can and seam the can. The arrow guide as a can route, actually it is involved a conveyor. PVS is stands for Pre- Vacuumizer Syruper where this machine operate for vacuum the juice can and fill syrup it has a valve where the used of valve is loaded a syrup to fill. SEAMER machine operate for seaming the juice can. Both machines have motor so it rotates counter clockwise. The output there is the conveyor, valves, and machine motor and it is operated start-stop when there is an error and the operator facing the HMI to control the machine.