20mA current loop
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I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included. When was the last time you saw any device use that or at least have that option? The problem is more relevant today than ever before, but I think that current loops are now a thing that you can find in a museum, or am I wrong there?
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
CodeWraith wrote:
I think that current loops are now a thing that you can find in a museum, or am I wrong there?
Lots of hardware in the maritime industry still using current loops today. Kongsberg, Baker Hughes, Hatteland, Rolls-Royce... many others, too many to name.
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Before about 35 years I was in contact with 20mA current loop. We used it because it was easy making galvanic isolation.
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CodeWraith wrote:
I think that current loops are now a thing that you can find in a museum, or am I wrong there?
Lots of hardware in the maritime industry still using current loops today. Kongsberg, Baker Hughes, Hatteland, Rolls-Royce... many others, too many to name.
Ah, ok. Reliability instead of shiny and new. Makes sense.
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included. When was the last time you saw any device use that or at least have that option? The problem is more relevant today than ever before, but I think that current loops are now a thing that you can find in a museum, or am I wrong there?
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
CodeWraith wrote:
I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included.
I actually run into things that use serial in the IoT realm and while i'm usually using a USB to serial bridge like a CP2102 or a CH340, some little devices break out to RS232. The thing is, I have no idea what a 20mA current loop is or why it could replace the functionality of a serial interface? And it's something I feel like maybe I should understand. What sorcery is this?
To err is human. Fortune favors the monsters.
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I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included. When was the last time you saw any device use that or at least have that option? The problem is more relevant today than ever before, but I think that current loops are now a thing that you can find in a museum, or am I wrong there?
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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Ah, ok. Reliability instead of shiny and new. Makes sense.
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included. When was the last time you saw any device use that or at least have that option? The problem is more relevant today than ever before, but I think that current loops are now a thing that you can find in a museum, or am I wrong there?
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
Last I heard of it was the Lenz RS-Bus used in model trains - no idea if it is still used, I just read about it back 5-10 years ago. I have been tempted to hook up a remote sensor with current source to run two wires only (as an alternative to 1-wire but less prone to noise or capacitive problems on longer runs). Never got off the ground though, and I do not remember what it was I wanted to sense, so it was probably not important. :)
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CodeWraith wrote:
I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included.
I actually run into things that use serial in the IoT realm and while i'm usually using a USB to serial bridge like a CP2102 or a CH340, some little devices break out to RS232. The thing is, I have no idea what a 20mA current loop is or why it could replace the functionality of a serial interface? And it's something I feel like maybe I should understand. What sorcery is this?
To err is human. Fortune favors the monsters.
Old and ancient magic, used for teletypes and later for computer terminals. As an old standard, it was slower than RS232, but is also known for its high noise immunity.
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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Old and ancient magic, used for teletypes and later for computer terminals. As an old standard, it was slower than RS232, but is also known for its high noise immunity.
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
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CodeWraith wrote:
also known for its high noise immunity
Cable length[^] is a limiting factor for RS232. Also the reason why some industries are still using current loops. :)
… or RS485 I’d say current loop is confined these days mostly to analog 4-20 mA sensors
Mircea
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… or RS485 I’d say current loop is confined these days mostly to analog 4-20 mA sensors
Mircea
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I just stumbled over an old construction article where an option to use a 20mA current loop instead of RS232 is included. When was the last time you saw any device use that or at least have that option? The problem is more relevant today than ever before, but I think that current loops are now a thing that you can find in a museum, or am I wrong there?
I have lived with several Zen masters - all of them were cats. His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
Hardly qualifies as a loop but I have a current sensing switch that turns on a device when a pump starts up. Monitors the current on the AC line to the pump.
>64 Some days the dragon wins. Suck it up.
