4 Channel DCSSR Assembly Instructions

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Revision as of 23:53, 10 November 2007 by Wjohn (talk | contribs) (→‎Design)
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Background

The DC SSR project was commenced at the request of Scott Nething, who wanted to control some DC Devices for Halloween. We worked on this project and had some prototype boards working for the shows, and I have subesquently tested the DC SSRs with LED MR16s, and dimmed them using PWM code from a RENARD.

Design

The board is a simple design, and follows the standard connection for an AC SSR COOP board. The RJ45 Socket provides the connection from the DC SSR to the Controller. The LED on the board indicates 5VDC is being supplied from the Controller to the OPTO.

The OPTO, which is different to the MCO3023Ms used on the AC SSR, is a K84PH, 16 pin DIP IC. I purchased mine from Mouser. 782-K847PH was the Mouser Part # and they cost $1.02 each, and here is the Datasheet The OPTO provides DC isolation from the Controller to the DC load. this is a safety feature, though some would suggest it could be deleted, I felt that will storms and electrical noise, it makes sense to isolate the PC and controller from the Lights.

The load switching is provided by MOSFETs. Mouser stock these parts, RFD14N05L, as part # 512-RFP14N05L and here is the Datasheet

There is a regulated 5V DC supply for the OPTOs, provided by either a 7805 or a 78L05 on the PCB. the PCB has mount holes for the TO-220 or TO-92 case style.

Euro style screw connectors are specificed for the board, and they are grouped in pairs (+/-) to make connections easy.

The DCSSR is design to switch DC loads between 0 and 30 Volts. The MOSFETs are rated to great than 10 Amps each, however as fitted to the PCB, I would limit to individual channel load to 2 to 3 Amps max. A suitable heatsink will be required.

Parts List

 512-RFP14N05L 4
 782-K847PH 1
 660-CF1/4C681J 5 
 660-CF1/4C471J 4 
 660-CF1/4C103J 4
 604-WP7104IT 1
 571-5202514 1
 863-MC78L05ACPRPG 1
 538-39890-0302 5 
 571-3902614 1

571-3902614 is an optional IC socket, the rest of the parts are the Mouser part # and quantity required.

Completed DC SSR