Answer / mahmoud zaki

DO this is digital Output signal it is be Come from PLC or
DCS to machine Or motor for ex ; DI this is Digital Input
signal it is come from switchs(limit switch - proximity
Switch ) To System (PLC or DCS)

Answer / sanjiv patel

DO means Digital Output
DI means Digital Input

DO or DI signal can have only two state 0 (Low = 0V ) or 1
(High = supply votlage i.e 5V / 12V /24V etc.).

In case of any floating value of signal state,either for
input or output, maloperation is possible depending upon
type of input or output deivice connected to it.

Normally less than 2/3 of supply voltage is not acceptable
for digital signal.

Answer / r.murugan

DO MEANS DIGITAL OUTPUT COMMAND WHETHER CAN BE DCS OR PLC
DI MEANS DIGITAL INPUT AS A FEEDBACK SIGNAL

Answer / biswajit pradhan

DO are digital outputs,that are given by controllers which may b a plc or dcs.it has only two states 1 or 0
ex- command from plc or dcs to open or close a valve is a DO generated.
DI are digital inputs that a controller whether plc or dcs receives from field.it also has 2 states 1 or 0.
ex- if a proxy sensor senses in fIeld,the feedback from proxy is a DI.

Answer / inst

digtal outputs

command which is given from plc,dcs to the respective field
ex:i have to on motor
command which is given to on motar is do
and we have check weather it got on r not that is status
which is getting to plc is digital input

Answer / faiyaz ahmad

DO-Digital out put its used to control the ESD system PSD system means ESD valve and PSD valve which one control through the DCS that is called Digital out put which signal coming from in DCS like proximity switch limit switch and proximity sensor means its on/off it is called Digital in put.and all the transmitter is analog input like pressure transmitter level transmitter flow transmitter and temperature transmitter and all the fire and gas system is analog input and 4 to 20 mA signal is analog out put like control valve

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