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Hello everyone myself Baradwas.
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In this course I will explain about
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foundation field bus protocol.
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This is a digital communication
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Using this we can send the field
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instruments data to the DCS system using
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digital communication.
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I will explain how this digital
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advantages, disadvantages,
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live system configuration,
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realtime images and videos. I will show
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you so that you will understand about FF
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the short form is FF foundation field
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Before going into the foundation field
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bus, let's discuss about the present the
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and these are 4 to 20 milliamp based
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signals which we are using to handle
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We are using 4 to 20 milliamp signals
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field instruments and DCS system.
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If you see here, this is a temperature
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transmitter. This is a pressure
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transmitter and this is a DP
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These instruments measures the
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respective process parameter
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like temperature, pressure, flow, level
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and then generates an equivalent 4 to 20
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milliamp basis signal.
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These instruments sends 4 to 20 milliamp
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based signals to the DCS system.
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The DCS system receives these signals
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and calculates the equivalent process
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So these are the measurement signals
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which we are using in our control
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This is the uh very popular
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and industry standard.
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So let us see how this 4 to 20 millia
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signals works in a brief way. Okay. I
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will take one example.
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Let's say we have a tank and I want to
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measure this tank level. Then I need one
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This level transmitter measures the tank
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level and sends equivalent 4 to 20
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This is the analog input.
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And then the DCS system
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updates this measurement to the
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operators on the computer screen. Right?
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The communication between the DCS system
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generally through Ethernet based
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We have some other protocols also
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available. Let's stick to the Ethernet
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Let's say I have a tank level of
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0%. There is no level in the tank.
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The level transmitter measures this tank
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level and generates equivalent
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As the range starts from 4 to 20
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miampere, the minimum range is 4
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miampere and the maximum range is 20
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Right now the tank level is 0
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percentage. That means it will send the
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minimum current output to the DCS
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system. What is the minimum output? It
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and then DCS updates this tank level to
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Let's say the tank level increased to
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Then again the transmitter calculates
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the tank level and sends equivalent
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current signal which is 8 milliampere.
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Then this system updates the tank level
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which is 25% to the operator graphics.
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Let's say tank level increases to 50%.
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The equivalent current signal is 12
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and then again this updates this tank
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level to the operator.
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Again tank level increases to 75%.
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What is the current output? It is 16
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miampere current signal and again DCS
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updates this reading to the operator.
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Let's say tank level reaches maximum
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What is the maximum current output? It
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Again the DCS receives this 20
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milliampere and then calculates the tank
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level and updates to the operator.
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See this is the popular and industry
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which we found in every industry. Now
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this complete analog signals are handled
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using 4 to 20 millia based current
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We are also using this 4 to 20 milliamp
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based current signals for the control
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to control the motor speed.
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So analog inputs and analog outputs
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these are mostly 4 to 20 millia based
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We have other signals also available
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but this is the most standard signal in
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I will explain digital communication
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alternative for these analog signals. So
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this is the most fundamental basic
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concepts for a engineer working with
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Thank you. I will meet you in the next
