Timeline for Best practice in transmitting sensor analog signal over longer distances (approx. 100') -- in cost sensitive products for microcontrollers
Current License: CC BY-SA 4.0
13 events
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| Jan 17, 2020 at 13:59 | comment | added | J... | @cstanto That's certainly true for some sensors, but it is absolutely not true for all sensors. In any case, it stands to reason that the people who trouble your tech support are people who don't know what they're doing. It's not going to be a representative cross-section of your customers. In any case, analog I/O is ubiquitous, current, and very much alive. Like anything, it is obviously not the right solution for everything, but, like anything, it still very much has places where it remains a top choice. | |
| Jan 17, 2020 at 9:44 | comment | added | cstanto | @J Things can happen in a sensor that require attention, without it being broken. Being able to see to it without taking your whole system apart to get to it is priceless. You also dont necessarily have to remove sensors to calibrate them, if the system is designed properly. | |
| Jan 17, 2020 at 9:42 | comment | added | cstanto | @J Nope, definitely talking about people working for big firms. We didnt deal with tinkerers and hobbyists. Youd be amazed how many people building multimillion dollar machines dont have a clue what theyre doing. Ive seen mechanical engineers, managers etc with no background in electronics lumped with sourcing sensors and daq systems. | |
| Jan 17, 2020 at 2:07 | comment | added | J... | @cstanto Sounds like you're talking about neophytes and small tinkerers who don't really know what they're doing. People building serious multimillion dollar machines do not require such handholding when designing and implementing a system. If a sensor breaks or needs calibration you need to remove it - I don't see how digital comms changes that, to be honest. I use both digital and analogue devices - lots of them, all flavours, protocols, and types - and they each have their benefits and drawbacks. I still think they both have relevant places in modern automation. | |
| Jan 16, 2020 at 9:51 | comment | added | cstanto | @J Digital comms allow a lot of diagnostics, calibration and maintainance to be done without removing the sensor/instrument from the application and opening it up, which can be hugely beneficial to end users. Often though, we found that that wasnt always considered until we explained it to them. | |
| Jan 16, 2020 at 9:51 | comment | added | cstanto | @J Ive no doubt theres an element of sell them the newest thing for the sake of it, and some simpler applications really dont require much more than an analogue output. But in our experience, getting people set up with outputs like modbus over RS485 rather than analog led to much less time spent providing technical support to customers because they didnt understand how to properly convert their 4-20mA into something human readable, or how to calibrate their sensor with potentiometers etc. | |
| Jan 15, 2020 at 22:48 | comment | added | J... | @cstanto Fair, and I don't deny the utility of digital comms for lots of devices, but there are also plenty of simple components in machines that really don't need more than a plain analog loop, and the benefits of not overcomplicating the system can't be overlooked either. It's still one more thing that can fail, and I'm certainly seeing (and designing) brand new equipment with a healthy amount of analog I/O in the I/O mix. In my experience manufacturers are eager to recommend the newest thing just to keep you up to date with what's out there - it doesn't mean that it's always the best fit. | |
| Jan 15, 2020 at 14:15 | comment | added | cstanto | ...With "industry 4.0" and the increasing push towards smart sensors 4-20mA loops are only going to get pushed out of the market over time for all but niche applications. | |
| Jan 15, 2020 at 14:15 | comment | added | cstanto | @J Yes, I understand that new devices are still being designed and sold with 4-20mA loops, I spent 5 years working for a firm that did just that, but a large chunk of that popularity is because theyre being fitted into systems that dont have more modern digital comms capabilities. We would always recommend CAN/RS232/RS485 variants of our instruments and sensors over 4-20mA variants unless the customer was dead set against them and knew how to acquire data from a 4-20, as it allowed more sophisticated control and diagnostic capabilities. cont... | |
| Jan 14, 2020 at 22:36 | comment | added | J... | @NateS. And you'd be wrong. It is very much a top choice, even today. | |
| Jan 14, 2020 at 22:34 | comment | added | Nate S. | @J..., cstanto said legacy system, not legacy devices. Of course there are modern devices designed to interface with legacy systems, and vice versa. But if one were to design a system from the ground up today, I doubt that communication protocol would be a top choice. | |
| Jan 14, 2020 at 16:00 | comment | added | J... | 4-20mA devices are not legacy devices - they are bread and butter in the industrial world and the shelves are packed full of brand new devices of all sorts that use 4-20mA analog output. | |
| Jan 13, 2020 at 15:55 | history | answered | cstanto | CC BY-SA 4.0 |