Emerson Exchange 365

Non-Isolated Discrete Input Card/ Isolated Discrete Input Card

Hello,

I have few questions as below.

1. can we replace Non-Isolated Discrete Input Card with Isolated Discrete Input Card ? (As i understood on isolated discrete input card we will need to jumper all "-" terminal with 24V DC- from source and we will need to jumper all "+" terminal with 24V DC+ from source and then it will work same as non isolated discrete input card).

2. can we say 32 Channel High Side Card and 24V DC Dry Contact Card are non isolated card discrete input cards ?

Can you please advise ?

Thanks,

Mitesh Maniar

Mitesh Maniar

• 20 Mar 2018 3:02 PM
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4 Replies

• Andre Dicaire

  

  • 20 Mar 2018 6:43 PM

  You can certainly use an Isolated DI Card in place of the standard DI 24 VDC. The standard DI 24 VDC places the sensing circuit on the 24 VDC side of the field contact. This provides current limiting through the load resistor and prevents a short do ground. In fact, the field contact is a short to ground as the return wire is connected to DC Common. The card is Namur compliant in that it can be used with a Namur discrete device that can differentiate between a wiring fault (Open Circuit or short circuit) and a signal state (Open Contact, closed contact). If used with a standard switch, the fault conditions appear as valid signal states. You can use this with an end of line resistor pack that enhances a simple switch contact to provide the differentiation mentioned above.
  
  In applications where low side sensing is desired, the Isolated Discrete card can be used. By connecting the "-" terminals together to ground (DC Common), you can send 24VDC to the field contact via a marshaling strip, and connect the return signal to the Card's "+" terminal.
  
  The 32 Channel cards are non isolated. They are both high side cards. The DI senses signal on the high side. The return signals are grounded together on a marshaling strip. Similarly, the DO drives the output signal on the + and all return wires and grounded together at the marshaling terminals.
  
  Emerson has Field termination assemblies for these cards, using Mass Termination terminal blocks. The Field termination assemblies provide additional signal conditioning such that you can wire the field signals to the FTA in low side sensing arrangements.

  Andre Dicaire

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• Mitesh Maniar

  

  • 21 Mar 2018 6:18 AM

  In reply to Andre Dicaire:

  Thanks Andre for your reply and detail explanation.
  
  I have got few other question. can you please advise ?
  
  1. do we have any non isolated type discrete input card available in Delta V M-Series and S-Series I/O ? Actually i was comparing it with PLC5 Non Isolated Card and thinking for best solution to replace Non Isolated Discrete Input Card of PLC5 with equivalent Delta V Card and i felt it could be isolated discrete input cards of Delta V but since i am learning Delta V , i am not 100% sure if i can do that so ask question here. thanks for your reply.
  
  Regards,
  Mitesh Maniar

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• Andre Dicaire

  

  • 21 Mar 2018 4:15 PM

  In reply to Mitesh Maniar:

  Yes, we have non-isolated DI cards, but if you are replacing a PLC5, you have to review the wiring circuits and understand if the existing field wiring can be connected to the available cards. The 8 channel, 16 channel (SOE) and 32 channel DI cards in the M-series 2 cards and S-series are high side sensing. The FTA for the 32 channel DI card can be wired to the field as low side. You should review the product data sheets available on line for more details on each card.
  
  Google "M-series Mass Connection Solutions". There are also new Plus DI cards with diagnostic features to work with the Connection solution.
  
  For AC powered signals, DeltaV has an 8 channel system powered DI, and an 8 channel Isolated DI.
  
  I'm not going to recommend what product you should use. That's your responsibility.

  Andre Dicaire

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• Mitesh Maniar

  

  • 22 Mar 2018 4:31 AM

  In reply to Andre Dicaire:

  Thank you Andre again for all your help and time.
  
  Yes i will do some study and i am just learning some stuff so sorry for many questions.
  
  Thanks for all your help.
  
  Regards,
  Mitesh Maniar

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