Hi, I'm designing ESD protections to 4-20 loop interface on Beagle Bone analogic input. which is the clamp voltage of any TVS zener that i could use? Thxs
El martes, 10 de abril de 2018 a las 16:04:08 UTC+2, robson...@gmail.com escribió: > Hi > > As I am also working on beaglebone <https://beagleboard.org/black> to > measure 4-20mA sensor output with Receiver module > <https://store.ncd.io/product/4-channel-4-20-ma-current-loop-receiver-16-bit-ads1115-i2c-mini-module/> > > using less power > > can anyone help me out with code to interface the 4-20mA current loop > Receiver with beaglebone please ?? > > > > > On Thursday, August 18, 2016 at 10:36:14 PM UTC+5:30, drhun...@gmail.com > wrote: >> >> There is a TI reference design for 4-20mA loop interfaces >> http://www.ti.com/tool/tida-00550. It is designed as a cape. >> Iain >> >> On Thursday, August 18, 2016 at 4:24:45 PM UTC+1, Graham wrote: >>> >>> If you would think to Google "4-20 mA receiver" you could learn a lot. >>> >>> Peripheral IC's from TI and Maxim that have most everything you need all >>> ready designed in. >>> >>> Modules you could interface to the BBB, etc. >>> >>> Application notes on how to design receivers, and things to worry about, >>> common system problems that people have had with this circuit for the last >>> 50 years. >>> >>> Good luck. >>> >>> == >>> >>> >>> >>> >>> >>> On Thursday, August 18, 2016 at 10:03:12 AM UTC-5, Przemek Klosowski >>> wrote: >>>> >>>> On 8/17/2016 5:26 PM, bali...@gmail.com wrote: >>>> >>>>> I am wondering if a beaglebone black can be used to measure industrial >>>>> 4-20 ma loops? I see there is an ADC feature, but the voltage range is >>>>> only to 1.8V. Is it possible to set it up to work with the standard >>>>> 24VDC >>>>> circuitry involved with most 4-20ma loops? >>>>> >>>>> A 90 ohm resistor carrying 20mA will develop a voltage of 1.8V. This >>>> is cutting it a little close, so I recommend 68 ohm, which is a more >>>> standard/easier to find value anyway. So, just terminate your 4-20mA line >>>> with this resistor, and connect it to the Beaglebone analog input. Of >>>> course if you're in an industrial environment you need to watch out for >>>> transients, noise and interference, especially since the Beaglebone inputs >>>> are famously fragile, so include some serious input protection (e.g. four >>>> diodes connected as two anti-parallel 2-diode chains, with a filter cap >>>> across it and maybe some series resistance). Then again, you could follow >>>> evilwulfie's advice to use a dedicated buffer op-amp. >>>> >>>> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/3b161515-7f62-420d-9732-afa02d710f33n%40googlegroups.com.
