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First connection to a USC-B3-R20


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Hello all,

I've been trying for some time to connect to this new controller of mine, a Unistream model USC-B3-R20.

As I've seen in the help section, the default IP address is:


I've changed my adapter's ipv4 settings to the same ones, just the IP to


Still getting a red X when trying to communicate with the controller.

Would be glad for some help in the matter.


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  • MVP 2023

@Flex727 - that's a basic PLC product.  The -B3's are limited - no screen to see UniApps until first contact has been made.  No USB Mini port to plug into, either, like on the -B5 or the -B10.


@Yanivle - If Flex's suggestions don't work, try these other "default" IPs - or

If that doesn't work I'd get the application with the IP addresses I wanted to the PLC via the USB host port using an Action file.  Search the Help on "USB Action Files" to see how to set these up.


Joe T.




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  • MVP 2023

Yanivie, you don't have a DNS server named in the windows IP4 properties.  Depending on how you're connecting, this might be the issue......nothing knows where it is.  And does the gateway know this info, too?  As in....what is the gateway's normal address you have it set to, and does it also need to change.

cheers, Aus

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Hello all

@Flex727 I do manage to ping both addresses (CPU and Panel), I'm just connected right through my laptop's ethernet port using a standard CAT5e cable. Should I use a specific cable for this propose?

@Joe Tauser I did manage to use the Action file creator. I have confirmed the IP address of both PLC and HMI ( &, but still can't connect.

@Ausman I am connected from my laptop directly to the PLC ethernet port. Does this makes any sense?



Edited by Yanivle
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  • MVP 2023

For the settings you first showed, and now knowing how you are connecting, here's some tips.

1.  What you are doing is essentially a direct connection.  To do this, depending on your laptop, you may need a crossover cable.  Alternatively you can connect both the PLC and the laptop via a switch. 

2.  Your laptop is on the network as

3.  The laptop will become the DNS server, so put it's address into Preferred DNS server, and don't have anything in any of the Gateway areas.  You don't have a need for a gateway.

I would initially try things with the cable you are using and changing the addresses around as I suggest.  If your laptop is able to recognise the need for a crossover and does it itself, things will work ok.   If nothing still works, you will likely need the crossover cable, or do the connection with a switch in between.

I'm very tired this morning, so hope I've got this right!  If not someone else can hit me with a foam bat. 

I also suggest you google up networking a little more to learn some things that you perhaps don't know, due to not encountering issues that us oldies are well used to, but modern stuff gets around without any input from the user.

cheer, Aus

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