Emerson Exchange 365

CHARM Non IS DO 24VDC Isolated

Dear Sir or Madam,

I have  following query as regard to CHARM Non IS DO 24VDC Isolated.

 

 

The  customer specification has  two statements regarding the DO, first one,

If the digital output channel rating is less than 0.5 Amp then hermetically sealed relays have

to be used. Digital output modules shall support wet outputs.

second one is,

All DO channels shall drive solenoid valves, LED’s & other miscellaneous devices. Each

channel of the module should support maximum load of 500 mA.

 Interposing relays to be utilized if a power load exceeds 500mA unless Supplier has a suitable higher powered / lower density output module that can safely be used.

In our case, say if less than 0.5Amp, which the charms, do we need the hermetically sealed relays?

 

Regards,

 

 

cbpun

• 9 Oct 2013 1:45 PM
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3 Replies

• Otto Von Steele

  

  • 9 Oct 2013 5:33 PM

  You're talking about several things here.  The limitation for the DO 24VDC high-side CHARM is 100mA.  The limitation for the 24VDC isolated CHARM is 1 A.  It all depends on the potential load of the output.

  Per the details above, you'd probably want to go with DO 24VDC high-side CHARMs with the interposing relays since typically the load of the relay is <100mA.  You could go with 24VDC isolated CHARMS as long as you know the load is going to be below 1A.  If this is unknown, high-side CHARMS with relays is the best option.

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• Otto Von Steele

  

  • 9 Oct 2013 8:27 PM

  Sorry, another option is also the DO 24VDC high-side CHARM with a relay output term block (supports up to like 4 A switching current) if they are ok with the relay being the CHARM term block.

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• cbpun

  

  • 10 Oct 2013 8:15 AM

  Thank you for your advice. Much appreciated.

   

  From: Otto Von Steele [mailto:bounce-WJelli@community.emerson.com]
  Sent: Thursday, October 10, 2013 4:28 AM
  To: DeltaV@community.emerson.com
  Subject: RE: [EE365 DeltaV Track] CHARM Non IS DO 24VDC Isolated

   

  Sorry, another option is also the DO 24VDC high-side CHARM with a relay output term block (supports up to like 4 A switching current) if they are ok with the relay being the CHARM term block.

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