What is an Operator Training Simulator (OTS)

OTS is an acronym of Operator training simulator.

But what does it all about ? And What it is meant for ? What stages does it have? Lets discuss in below.

It may be difficult for me to tell actual importance of OTS based on my experience.

If i can say in simple steps:

• It is a verification of design cases which EPC developoed in Steady state.
• The performance of an operator can be measured using OTS models.
• High fidelity OTS dynamic models are used as studies for potential improvements in industries.
• Training operators with a low cost and in quicker fashion can be done using OTS models.the result will be industries can save start up times by few days. can test servo problem,regulatory problem etc
• Operator's will get a feel of DCS and ESD systems. 
• etc..

What are all involved in OTS: 

• OTS will have a dynamic model which is a replica of plant means it will have process control(PID controllers) where OTS engineer has to take care of various controller arrangement some are simple like normal pressure, temperature controller and level controllers. Other types are cascade and split range etc.Controller narratives has to be thoroughly studied for complex controller arrangements.
• Thermo preparation for matching the HMB(Heat and Mass Balance). Here OTS engineer should have a sound knowledge on Flash and importance of various Phase diagrams and flashes like TP,PH,RU,PU,PVF Most important thing is OTS engineer should understand the options available for Enthalpy,Density,Entropy,Vapor pressure,Viscosity etc. Here test loops has to be prepared for verifying Vapor fractions for mixed phase streams, Duties of ex-changers, Separators to check the separation. 
• Models will be integrated with ESD which is emergency shutdown system where OTS engineers are responsible for ESD flow sheeting  to do so OTS engineer require a knowledge on cause and effect diagrams.
• eg: Level in tank: ESD wont allow the Shut down valve(downstream of tank) to open unless it reaches minimum level.not necessary for all separators. 2) Until the column get pressurized the shut down valves wont allow to inject solvent.
• Models will be integrated with DCS by mar shelling tags which is again OTS engineer will do. here this might be called as OLE (object linking and embedding) means giving one object value to other object value. marshaling tags means connecting tags of DCS and tags of dynamic model.
• Graphics has to build, which is required for FOD (Field operating device - contains all field valves) PC and DCS graphics for DCS. Some times OTS engineer or integration engineer will take care of it. And this graphics has to be integrated with dynamic model. 
• Malfunction addition. This is very helpful because most of the real things that are abnormal which are happening are observed in terms of Delta P in OTS models so malfunction is nothing but,  if one event happens what are all operator variables has to be taken care kind of studies will be done. This is something which doesn't planned anywhere and here OTS engineer forcefully fails the instrument or equipment. Cause and effect diagrams will be referred during this testing. Eg. For a furnace, failing the air flow leads to trip in furnace. 

So in-precise OTS will involve Dynamic model,Thermo preparation, ESD flow sheeting, DCS tags embedding,Graphics preparation for FOD,Malfunctions and integration of all these things.


What stages does it have:

• Scope analysis : Where scope will be decided what to model and what not to model. review of so many documents which contains modeling guidelines,Datasheets review etc.
• MAT: Model acceptance test. Thermo selection and HMB cross verification plus Modelling will start for which are agreed.
• FAT: Factory acceptance test, in this stage model will be integrated with fod graphics, DCS graphics with Marshaling and ESD integration. Minimum 2 to 3 operators will test the model. One may sit on fod other may take care of dcs etc. Multiple machines with all the necessary integration will be tested here. Eg.  Furnace start up sequence with all the necessary steps will be tested. It is not just like on and off everything has to be done in a stipulated time if not sequence will go back to initial position. 
• SAT:Sight acceptance test which will be conducted at industry the ultimate end user.Final delivery for an OTS project. 

Software's available for developing OTS models:

These OTS dynamic models are developed in many software's some of them are listed below.The only difference capabilities of software's differ from software to software. Capabilities in the sense Thermo options availability, usability, customization etc.

DYNISIM - FROM SIMSCI 
VISUAL MODELER - FROM OMEGA LAND or YOKOGAWA.
UNISIM -FROM HONEYWELL.

The objective is same for any software to develop a dynamic model.