• Not Answered

CHARMS IS DO 45ma

I have a vendor that is looking to use a Ross IS solenoid with the following parameters with CHARMS IS DO 45ma.

Voltage 24VDC, 1.6W, I (Inrush & Holding 0.50 Amps), Resistance 275 Ω.  

Is this compatible with the CHARMS IS DO 45ma that CHARMS Power Req. 78ma at 24VDC

RK914

rk914

• 3 Jun 2025 1:36 PM
• Cancel

2 Replies

• Andre Dicaire

  

  • 3 Jun 2025 5:36 PM

  The Product Data Sheet for the IS DO indicates a max of 45mA at 11 V. That would be 0.495 W. That does not cover your 1.6W. I'm assuming the current is 0.050 Amps. 0.5 Amps would not be within intrinsic safety energy levels.
  
  The 78mA at 24 VDC is the total power you would need from the Bulk Power supplies to operate the CHARM and drive the field signal. This information is provided for the Power calculations, not the Power to the field. To maintain the energy level to prevent an ignition source in the field, the channel is limited to operate at 11 V with max 45 mA. That is what you have to work with for selecting your field device.
  
  
  Looks to me like the Ross IS Solenoid and the IS DO 45mA CHARM are not a match.

  Andre Dicaire

  • Cancel
• rk914

  

  • 5 Jun 2025 5:42 PM

  In reply to Andre Dicaire:

  Andre, thank you for the reply and confirmation. The spec does show +/- 10% for the 78ma@24VDC, does that 10% apply to the output of 45ma@11V?

  RK914

  • Cancel