Anything that makes it easier to reliably keep the radio’s powered up is worth the effort. I know the new auto reset on power overload firmware is a game changer here. If being able to accurately read voltage makes this feature easier to support in future devices it seems like $5/port would be worth it. Avoiding even one un-necessary outage would easily be worth the added cost.
Steve B. From: Af [mailto:[email protected]] On Behalf Of Forrest Christian (List Account) Sent: Wednesday, September 23, 2015 8:11 PM To: af Subject: [AFMUG] Injector Current Monitoring and Overcurrent Protection. 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 <mailto:[email protected]> [email protected] | <http://www.packetflux.com/> http://www.packetflux.com <http://www.linkedin.com/in/fwchristian> <http://facebook.com/packetflux> <http://twitter.com/@packetflux> <http://ws-stats.appspot.com/t/pixel.png?e=setup_page_outlook_compose> <http://ws-stats.appspot.com/t/pixel.png?e=setup_page_outlook_active&uid=e965778f9a351fad7a8a860dffc144ce> <http://ws-stats.appspot.com/t/pixel.png?e=setup_page_outlook_active&uid=e965778f9a351fad7a8a860dffc144ce>
