What is NODE in DCS?
Answers were Sorted based on User's Feedback
Answer / mahesh
Nodes are I/O communication protocols.
Eg: DCS is the master controller, then Nodes slaves.
Nodes are normally receives data from field instruments and processes in DCS.
Is This Answer Correct ? | 8 Yes | 2 No |
Answer / ranjith
In Mahesh's answer, it says 'Nodes are I/O communication protocols' this part is wrong.
In a typical DCS architecture from top you have got,
0. MES/SAP/
1. Operator station
2. Runtime/Database/Historian/Batch/Gateway & Engineering Servers
3. Controller
4. IO nodes
5. Marshalling Panel
6. ...(I'll stop here)
The IOs are generally not clustered with the Controllers, IOs will be in a different panel communicating with the controller in various communication protocols(exceptions are there).
There will be a slave module communicating to the master(Controller) and also communicating to the IOs connected to its Backplane/Bus of the slave. This slave module and the IOs are collectively called as 'Node'.
There will be multiple nodes due to segregation of IOs(Plant/unit/Process part) or to distribute the slave module's load (different manufacturer has different IO density specified or may be limitation of protocol).
Now imagine wiring the whole bunch of field signal cables to your control room...!
An alternative is to take a communication cable from 'Main control Room/Center' to 'Remote/Sub station' may be kilometers apart and enjoy limited wiring.
Total number of nodes are limited by the communication protocols itself. (Payload, Noise, Cycle Time ...)
Further reading:
Industrial Communication Protocols /Fieldbus
Is This Answer Correct ? | 5 Yes | 0 No |
what is the difference between impact plate n coriolis type solid flow meters n how they works....n which one is better
Pls can anybody tell me how much memory plc's has?in byte or in Kb
how we can measure the interface level?is it possible to measure interface level with dp or pressure transmitter?
define feed forward control loop with example and drawing?
HOW TO CHECK THERMOCOUPLE AND RTD & WHAT IS THE DIFFERENCE BETWEEN THERMOCOUPLE AND RTD
what is axial shift n what is differential expansion in turbine? how many sensor probes r mounted for this n how it works?
Lux meter is the measuring device to measure the lux level of lighting fixture. in industrial sector two types of lighting fixture is being used as street lighting purpose 1. HPSV (Sodium) and 2. HPMV (Mercury). HPMV having white light which is an combination of red, blue and yellow colour, while HPSV haivng Yellow lighting. in HPSV red & blue colour will be absent. during measurement of the lux level of HPSV and HPMV fixture. 1. Lux meter can measure the actual lux level of both fixture? 2. or it will show false reading for HPSV fixture light as it has only yellow light present. please give me answer
why any measurement made interms of pressure is more accurate ? to be more precise most of the flow velocity is made interms of pressure and it is accurate. what is the reason behind pressure measurement being accurate ?
Give me best instrumentation Books name..Ple...
Valve positioner and actuators in detail.
Boiler flame scanner advantage?
0 Answers Fluke, Petrochemicals, Tata Chemicals,
Why some transmitter shows flow in MMWC and some in TPH?