LabVIEW temperature controlled applications can be done in one of two ways:
(A) The LabVIEW executable has a PID control loop that monitors a thermocouple or varistor or RTD and controls the heat source
(B) LabVIEW acts as a “Front End” or host as a sub component does the temperature control such as one of these components:
- Off the shelf controller made by a company such as Watlow, Omron, Omega, Chromalox. These controller typically communicate with LabVIEW using RS232, RS485, RS422, 4-20mA output / input, 0-10V output /input
- Industrial grade PLC such as Siemens, fujitsu, Allen Bradley
- LabVIEW PXI – Real Time system. (Using Shared variables, network communication).
When making a decision on which approach to use, there are many considerations to take into account. These are:
- How tight is your control loop? (What frequency does it need to run at?)
- What damage can happen to the equipment being controlled or product being processed?
- What could happen as a result of a computer hang or crash?
- How much data do you need to save per day? Per test run or production run?
- Do you need SPC charts for quality control
- Do you need historical data reporting based on lot ID or batch run?