vikkipro

Can anyone tell me that what is the difference between Normal DI modules and Namur DI Modules?

Not only DI Modules, Why we are going for Namur type of modules? even in Fail safe modules also, We are using Namur Modules. I want to know about Namur Signal Modules.

dear vikki 

According to your question there is a concept of DI line monitoring or fault detection which is essential in ESD systems also F&G systems where 0 and 1 is not enough you want also to detect if channel is faulty 

for this concept you need to install 2 resistances one parralel to your contact and the other one is series so that

Rs= series resistant, Rp= parallel resistance , V = voltage, I= Current.

if I=0 then open circuit which is fault

if I=V/(Rp+Rs) then it's digital 0, off

if I=V/Rs then it's digital 1, on

if I=V/0 then it's a short circuit

this concept means the module is able to detect levels of current 

Namur instruments is used in areas normal contact is not allowed and normally it works in 8-9 volt not 24 VDC as usual in normal PLC modules

all NAMUR modules equipped with fault detection concept while not all fault detection modules are Namur

in short if you need fault detection in the DI you can use Namur modules or search for a fault detection ( wire break, short circuit ) modules