Scan Bus A 1-wire : Invalid 1-wire code found!

[OZ1AXG]

Hi

I put together 4 temp sensores on 1-wire connected to BUS-A.

When scanning for new devices i get a error message:  Invalid 1-wire code found!

how can i fix this ?

PS: When going back to my "old" setup with one temperature sensor... theres no problem the device gets registered and can measure the temperature.

Im using :

Company   : Microbit
Product   : 1216H WebSwitch
Software  : 2.3
Hardware  : 2
Bootloader: 1.10
Build     : Feb 10 2012 13:27:32
S/N       : 1939
PID       : 4
Uptime    : 87980
=========================
Max available memory = 16301 bytes

[OZ1AXG]

Hi

I updated firmware to newest version and Im stil getting the "Invalid 1-wire code found!" error message when scanning BUS-A

Company   : Microbit
Product   : 1216H WebSwitch
Model     : Standard 1216L-4 or older
Software  : 3.3
Hardware  : 2
Bootloader: 1.10
Build     : Jun 12 2013 12:18:31

[ON4AOI]

I thought there could be only 2 temp sensores connected,
1 on BUS-A and 1 on BUS-B since they don't have a unique code
to separate them from each other.

Guy ON4OI

[OZ1AXG]

Hi

According to the product specs :
http://www.remoterig.com/wp/?page_id=166

Options    :
Inputs for up to 25 temperature sensors (single wire bus DS18B20)
2 x Digital Inputs

I read this as the web switch can handle up to 25 DS18B20 on a single wire.
Perhaps someone from Microbit can veryfy this ?

[Tytn]

Hi

I had the same problem just the other day.
I used only one sensor.
The cause was a mistake on my part were i had attached the sensor cables to the wrong port. The solution was to just switch the cable placement.

I think you have to scan and save a device at a time. You could probably not scan and save multiple (previously never attached and scanned) sensors to the webswitch.
Try attatching them one at a time, scan then submit them. After that you attach the chain of sensors and check if you get any temperature data.

I hope this helps you.
/Tytn

[Jan (Microbit)]

Every 1-wire device has an unique ID. The Webswitch can handle up to a total of 25 1-wire devices(sum of Bus A and B). Adding one at a time is a good suggestion.

[OZ1AXG]

Easyer said than done  They are all soldered directly onto a single cable - so not so easy to take a part again ...

The error message im getting - what does it mean ?

Flam

[Tytn]

Though luck 

I guess the error message is coupled to the way the 1-Wire protocol works. Like Jan said, every 1-wire device has a unique id used as a identifier during communications. When the bus master (webswitch) searches for a new (that has a unknown ID) slave device, is limited to only registering one device at a time by its search algorithm.
But this is all speculation on my part.

How does your network topology (structure) look?
There are some that are not suitable for use with 1-wire, due to signal reflections and signal cancellations, like:
     (S)  (S)
       \   /
(M)---¤---(S)  Or  (M)------(S)------¤--------¤------(S)
       /   \                                       |           |
    (S)   (S)                       [long cable]     [long cable]
                                                    |           |
                                                  (S)        (S)
Optimally the slaves should be linked in a linear fashion, like: (M)---(S)---(S)---(S)---(S).

/Tytn

[Jan (Microbit)]

I only suggested to add one 1-wire device at a time in order to debug what is causing the error you see. Normally it should be possible to scan and find multiple devices simultaneously.

The error message you get is due to that the WS gets an invalid answer/code from some of the devices on the bus.

[OZ1AXG]

im using this config:
(M)---(S)---(S)---(S)---(S)

4 identical type Devices (4x temp sensor).

I guess i can put connectors on it but nice to know that WS is capable of scanning more than one new device connect at the time.

[Tytn]

Okej good to hear that i was wrong 

/Tytn

[OZ1AXG]

Epilog

After some error/fault finding - it turned out that one of the sensors didnt work. Not sure excately why i get the invalid device error with this one ? The soldering and wireing is correct and there are no short circuits detected.

Once the faulty one was removed, there was no problem detecting multiple sensores in one scan.
 

[Jan (Microbit)]

Excellent!