Another capture of the same network.
Type: Posts; User: timtanguay
Another capture of the same network.
Was hoping you fine folks might be able to shed some light on this reading.
Battery operated scope, probe attached to one side of network, ground to other side.
I'm thinking this looks like...
Lonworks network with communication issues. When I hook up a certain run of controllers it takes down the whole network and I get a bunch of unacknowledged packets and all of the controllers drop out...
That's not a very nice thing to call someone.
😆
Once again, great reply. Thank you for such a complete reply. It is rare indeed to get such thorough and well thought out information.
What is the best procedure for the reference line? Should you just run 18/3 or 18/4 twisted and connect all of the references together and leave it floating?
Would line resistance drop become...
Amazing. I need to reread this when i get home to properly digest it. You've answered a couple questions I had and also given me more questions.
Thank you for taking the time to type that out
I think the pickiest part of rs-485 is the relatively small trigger of +/- 200mV which can make biasing tricky in some cases because the recommended EoL resistor can in some cases push the a/b...
It's a bit of a weird problem. When I hook this run back up, it takes nearly out nearly everything on the router. The whole floor drops communication.
Could there be a device causing a bunch of...
Is it possible to use wireshark with a lonworks usb adaptor? I've got the issue isolated down to a trunk of about 1 dozen daisy chained devices. My EoL resistor seemed to be borked on that branch,...
Hey,
I'm looking for a scope to help with comms issues on rs-485,rs-232, and tp/ft-10 busses.
What do you all recommend?.
Also, are there any references around to learn what these comm...
Much better accuracy, sensitivity, faster, low pass filter to get accurate measurements off of output of VFD, faster min max, larger resistance range, has a low Z mode for more accurate measurement...
I went with a fluke 902. I like it so far and will be a good companion to my fluke 87v
I think they have a firmware fix for that.
Thanks for the input everyone. I ended up buying a new in box 87V for a song and a 902 for amps. I'm sure I will be well serviced by both. I'm still tempted by the 289, I'll probably end up...
My next question was if you'd personally owned the meter. Thanks for sharing. I'm having a hard time finding the 87V and the 289 locally. I typically like to have a meter in hand before deciding...
I work on drives ALL the time. This is kind of the main reason I was thinking about the 289. How useful do you find the graphing function to be? What are the main reasons you find yourself...
Very good to know. Thank you.
Curious if anyone doing commercial and industrial work uses the Fluke 289 as their goto meter? It's a big honking, heavy meter. Will it stand up to typical field use?
I've narrowed the field...
True! Although I just discovered the fluke 279fc with thermal imaging. I need to do some digging on that. I was hoping to get a visual ir or flir c3 camera soon as well. Decisions to make!
I already have a decent fluke DMM, I was mostly looking to replace my clamp meter which doesn't have test lead ports for generalized maintenance and trouble shooting.
I think the testo is...
Good to know. I was hoping you find a fluke clamp meter with a range into the meg-ohm but I suspect it doesn't exist.
I was looking at the testo 770-3 but I'm hesitant to move away from...
I really like my fluke dmm. Any idea if there is a flukey clamp meter with a better ohm range than the 902?
I currently own and like using my fluke CNX series meter. I've had it 5 or 6 years and it's never failed me.
It annoys me that I need to carry a separate clamp meter (that only reads amps). I...
The necromancer has arrived!
That wouldn't take into consideration the latent load though. There is a LOT of moisture to remove from that air. This has an approximate SHR of around 0.4 (40% sensible, 60% latent)
In this particular instance, dehumidification is going to make up a large portion of the load. I just dropped the points on a psychro chart. There is going to be a LOT of condensation here.
Is there a reason that outside air will not be used? I was under the impression that gyms etc. had pretty substantial outside air requirements in most jurisdictions.
Fastastic tips. Thank you.
Oh man. I can't tell you how many service valves I've come across that people have mangled with crescent wrenches or toothed tools. Then they wonder why they leak by after the packing gets...
I can't believe you lot haven't suggested JB Weld yet. It repairs a multitude of sins.
But seriously OP, why are you putting refrigerant into a system without leak checking? Shaft seals, oil...
This wouldnt be effective if you were pressurizing the system. As pressure of a gas increases, its ability to hold moisture decreases. This is why water condenses in an air compressors receiver,...
My pump took a kicking indeed. I wouldn't be surprised if it will need replacing or repairing in the near future. Thankfully the pumps and recovery units are all company owned. I would not have...
That isn't a bad idea at all actually. I bet a few jumbo tarps would do the trick to be honest.
Haha! Awesome. The cladding alone to cover the unit would be 1000's.
We had to cover a 1500 ton cooling tower in the dead of winter that was being built. That was fun. -25C. Couldnt build it...
I'm not sure how I would enclose a rooftop the size of a shippimg container lolol. Carrier N series are huge buggers.
Perfect. I am leaving my ballast open for future wet systems. By the sounds of it, if you are pulling a vacuum on a heavily contaminated system leaving the ballast open will possibly prevent some...
A picture of the motor name plate and the unit wiring diagram would be helpful
A picture of the motor name plate and the unit wiring diagram would be helpful
I was recently tasked with leak check and repairing an 80 ton roof top unit. Turns out that it had been open for over a year. She was saturated with water. After repair, iI changed out the...
I use a coaxial heat exchanger from a water-source heatpump that was being decomissioned. works like a hot-damn and prevents your recovery cylinder from stacking up.
Pitching and traps are generally for oil return, not for refrigerant. The exception in that diagram would the inverted trap at the top of the riser which prevents liquid refrigerant flowing from the...
Have you ohmed the motor out? Is it a multi tap motor? If so what did you find
Have you verified that you have power coming in to the unit?
Have you verified control voltage, and proper...
742621
As hack-ish as this is, I'm rather impressed with the ingenuity.
So you can dial in motor amps. You can make the sheave larger or smaller which increases and decreases the Sie of the pulley. Increasing speed increases amp draw of the motor, because it is doing...
Oh, that makes sense. I live in a rainforest area, its unusual to find a roof without water on it.
Why do they run the condensate line to the drain? Up here in BC, Canada they just drain it right onto the roof for the most part.
Leave a tip behind the filter lol.
Good tips, thanks. I guess the trick is to do it the same way every time to get consistent repeatable results.
Good call on replacing both to get the close rpms.
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