So, I think I've about got the design for the next iteration of injectors nailed down, with one exception.
I'm not quite sure what to do about overcurrent protection. Let me ask this question up front: How important is it to be able to read the current being drawn by each radio? In the current SyncInjectors, Airfiber injectors, and 5 channel PDU's, I do active overcurrent protection. In short, the microcontroller measures the current through each channel using a hall effect sensor and when it detects an overcurrent it just shuts off the port. The advantage of this is that we get very rough current measurements (like you can usually tell if a radio is on or off, or drawing more power than normal, but NOT anything close to an exact measurement), and I can somewhat adjust the response to the overcurrent to handle inrush and the like. This is also fairly expensive per port (like they add around $5 per injection port to the cost of the product). With the altered design I'm looking at the current measurement accuracy would go up for around the same cost. On the other hand, In the past I've just used self-resetting (aka PTC) fuses, which are simple and very robust, but don't end up with current reading as a side effect since the microcontroller doesn't get involved. I can definitely detect a overcurrent (aka fuse has been tripped) easily and expensively, but can't tell how much current is actually being drawn. My decision is coming down to a perceived value choice. Is it worth $5/port on an injector to be able to read the actual current used? -- *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 forre...@imach.com | http://www.packetflux.com <http://www.linkedin.com/in/fwchristian> <http://facebook.com/packetflux> <http://twitter.com/@packetflux>
