Automation Engineer Interview Questions and Answers :
What does HMI stand for?
Human Machine Interface
How many different HMI types are currently available and what are the major differences?
Different types of HMI starting with the ranging in sizes from; 4.3" to 12.1," or even bigger.
HMI comes standard with Windows CE and its own SDK, which allows the user to use any programming language to build an application.
What are the benefits of using both an HMI and PLC, as opposed to just a PLC?
The benefits of using an HMI along with a PLC are substantial. PLCs tend to be complex, with many wires connected to them, making it difficult to find the correct input to manually toggle.
With an HMI, the user can toggle PLC’s through memory, as opposed to having to re-wire.
HMIs also provide a real time view of the system, so if recipe memory in the PLC was to max out, the user could easily wipe its contents without having to disconnect the PLC.
What is a Baud Rate?
Baud, synonymous to symbols per second, or pulses per second, is often times referred to as the unit of the symbol rate.
It is the number of distinct symbol changes made to the transmission medium per second in a digitally modulated signal or a line code.
What communication protocols are applicable to our HMI line?
- RS232
- RS422
- RJ-45
Which PLC unit do I select if my PLC is not listed under compatible PLC’s?
Selecting a PLC depends on what protocol this PLC or controller uses.
If the controller uses Modbus RTU, then the user should select Modbus RTU Slave. If the controller uses ASCII, then the user should select the Universal ASCII slave.
What is Windows CE and what is the Codesy’s packet?
Windows CE in an embedded operating system, which translate to a very stripped and minimalistic copy of windows for smaller devices such as HMIs and cellular phones.
The Codesy’s packet is a proprietary third party software, which will give allow the user to program an HMI and PLC.
What type of touch panel do these HMI’s use?
TFT, which stands for Thin Film Transistor
How many controllers can I hook up to one HMI?
As many COM ports as that specific HMI has.
What programming language comes standard with the HMI?
ANSI C89