The goal of this blog post is to document my experience with the Omega PCC-SMD connector Looking for 5 People to Experiment with Thermocouple/RTD Connectors . The exercise was to provide feedback on Omega PCC-SMD-20 connector. This commentary is not a RoadTest Review in the formal sense. I labelled it a RoadTest Lite, meaning I applied the same same diligence required for a RoadTest except the application process was informal.
Documentation for the connector is available at the request page. The connector is advertised for “high volume production printed circuit boards.” I wondered how the connector would work in a non-production environment. My pitch was to to install the Omega PCC-SMD connector on a perf boards, those cheap printed circuit boards perforated with solder holes. These boards are used for development and the go-to circuit board for hobbyist.
The Omega PCC-SMD connector is used for connecting thermocouple, RTD, and/or thermistor probes to printed circuit boards. The flat bottoms of these connectors enable them to be solder directly to a PCB. The connector design ensure that the mating connector cannot be plugged in backwards.
I assumed the connector was both the clips and a binding post shown in the vendor picture. The Omega PCC-SMD connector are metal clips that are soldered to a PCB. The binding post (i.e. white mating connector) shown in the picture was not included. The picture is just an example of one type of connector that can be used with these clips. shabaz provided an example picture of another possible binding posts that would mate with this type of connector.
Two different types of perf boards was used for testing. A flimsy thin brown perf board and a more solid stiff green PCM material perf board. Actually only the brown board was used in the review. The material was much easier to cut and drill that the green boards.
The brown perf board [callout A] had edge pads that were wider spaced than the green perf board [callout C]. The edge pad spacing on the brown perf board gave greater flexibility in installing the clips (i.e. Omega PCC-SMD connector). The green board can work if needed. I didn't spend a lot of time looking at design options.
To mount the clips a hole is required [callout A,B] to hold a metal tab of the clips. The manufacture specs have a diagram for spacing. The tab on the clip and it's physical design [callout F,G] are suppose to prevent the clips from being inserted in the board incorrectly resulting in a reverse polarity of the connection. The mounting holes have to be there to enable the clip to lay flat on the PCB. The hole width (small and large) matches the tab width on the clip which is what ensures the clip cannot be installed incorrectly.
The first mounting attempt was to use the brown perf board edge connection. The mounting holes for the clips were created by drilling holes and using an knife to remove the material between the drilling. Two edge pads on the perf board were used for each clip. The second edge pad [callout D, E] used for mounting the clip could double as a point to interface with the board circuitry.
The second mounting attempt was using the brown perf board pre-drilled holes [callout H,I]. No hole drilling was required for this method. Material did need to be removed between the holes to make room for the clip mounting tab. The picture doesn't do it justice but one hole is larger than the other. Removing material was easily accomplished with a sharp knife. Four holes were used for each clip mounting [callout J]. The adjacent solder holes could be the interface point for the board circuit to the clip.
- Hole alignment and drilling for the clip mounting tab required some effort. Using the pre-drilled holes and cleaning out the material for mounting in the perf board made the task much easier and cleaner.
- Tinning the pads and holes before mounting clip made for easy installation. Some solder residue is left on the clips [callout D,E] but doesn't impend operation.
- Connection between the clips and the board circuit is possible with a few options.
- The clips themselves have a wide and a narrow ends to ensure correct polarization when mated with a binding posts. I didn’t have a binding posts to ensure the clip spacing was adequate as shown in the vendor spec sheet. This will require some focus to get it correct so the clip and binding post mate correctly. I got confused a number of times on correction orientation of the clip for mounting. The clip differences for polarization are slight. You have to focus on the details to get this right. You can see a mistake [callout J] on one install. I tinned one set of pads and discovered when I was mounting the connector, I needed different pads.
Overall, I was satisfied that the Omega PCC-SMD-20 connector could be used by a hobbyist in a perf board installation. Using the clip connectors does require some skills to solder and additional work to modify the boards but not beyond the capabilities of the hobbyist. If the Omega PCC-SMD-20 connector specifications are something required in a hobbyist project the connector can be accommodated.