RS232 to WiFi converter

sjt · Dec 24, 2018

Ken Roach said:
Drivers for virtual or USB-connected COM port devices often cannot keep up with such rapid changes to the framing settings. I recommend configuring the DF1 Full Duplex driver for the normal default settings (19200 baud, 8 data, 1 stop, no parity) rather than attempting to use Auto-Configure.

"Transparent Mode" is where I would focus my efforts.

I did try those settings and I have tried transparent mode with different permutations of other settings. Transparent mode seems logical from what I have read so far but no dice yet.

Thank you

Saffa · Dec 24, 2018

Do you have a second USB to serial converter? When troubleshooting something like this i like to set up RealTerm or PuTTy with known port settings and just try send single characters from one port to the other via the serial to Wifi. A lot easier to see what might be going wrong.

controlconcepts · Dec 25, 2018

One thing I also try with serial comms is to verify the settings through typing mode into a command prompt. This will also show if the com Port is in use. If it is open it will not show the com port. And if nothing has the comport open it will show all of the settings for that port. To me this is the most reliable way to see what the settings are. I've had plenty of situations with various ethernet to serial devices where settings don't get saved through a web browser or the manufacturer software. There have been times I even had to make the final comport settings through device manager. Hope this helps. Merry Christmas.

Firejo · Dec 26, 2018

You do need to the unit to be in Station mode if it is connecting to a WiFi router (which will be the Access Point even though most manufactures don't use that term anymore). In it's basic form, WiFi operates in a AP (Access Point) to SA (Station Adapter) mode with the SA's being end points connecting to AP's which is the access to the Ethernet network. Again, that is the basic setup. The terminology and capiblities have changed a lot however unless otherwise indicated a SA will only talk to an AP. There are AP devices that will talk to other AP devices but (typically) they both need to be configured to operate that way so unless you've configured both units (your RS232 to WiFi device and the WiFi router you are attempting to connect to) to do this or it will not work. So it will need to be in "Station" mode and the first task is to confirm that it is connected, with a communications path (it can be connected wireless but still not have a path for communications to work). Then you can focus on the serial side of things. Having said all of that, why convert to WiFi? The same company that you got the device from sells wireless serial devices for around the same price so unless your PC isn't at the same location that the PLC is then I don't see any reason to add two to three times the overhead to the data packets that WiFi does (you get added packets for Ethernet and more for WiFi). If you PC is not located where the PLC is then you are adding a significant amount of complexity in the connection. To be fair I have no idea how good or bad the serial radios are. My background comes from radios that start at around $1000 but I know for a fact that with them if you are inside 1000' without line of site and 5 miles with line of site you will get a rock solid connection. If this is an industrial application that requires a good connection to the PLC I would consider that option. Data-Linc Group's radios are the ones I'm thinking of but there are others out there just keep in mind that it is very much a "you get what you pay for" industry and sub $100 radios generally only work at a few hundred feet with line of site.
From what I've read so far (and I may have missed something) it sounds like you aren't making the connection to the WiFi router but even after you do there are going to be some challenges.
On one final note (for now), when/if you do get a connection all the way back to the PC, the "auto configure" feature in RSLinx will more than likely not work even though you have a path. Even though the comm port redirect software should be cleaning everything up, adding all of the overhead onto the DF-1 packets adds significant delays and latencies that the auto config feature doesn't like so don't rely on that to determine if you have a link.

sjt · Dec 26, 2018

Firejo said:
You do need to the unit to be in Station mode if it is connecting to a WiFi router (which will be the Access Point even though most manufactures don't use that term anymore). In it's basic form, WiFi operates in a AP (Access Point) to SA (Station Adapter) mode with the SA's being end points connecting to AP's which is the access to the Ethernet network. Again, that is the basic setup. The terminology and capiblities have changed a lot however unless otherwise indicated a SA will only talk to an AP. There are AP devices that will talk to other AP devices but (typically) they both need to be configured to operate that way so unless you've configured both units (your RS232 to WiFi device and the WiFi router you are attempting to connect to) to do this or it will not work. So it will need to be in "Station" mode and the first task is to confirm that it is connected, with a communications path (it can be connected wireless but still not have a path for communications to work). Then you can focus on the serial side of things. Having said all of that, why convert to WiFi? The same company that you got the device from sells wireless serial devices for around the same price so unless your PC isn't at the same location that the PLC is then I don't see any reason to add two to three times the overhead to the data packets that WiFi does (you get added packets for Ethernet and more for WiFi). If you PC is not located where the PLC is then you are adding a significant amount of complexity in the connection. To be fair I have no idea how good or bad the serial radios are. My background comes from radios that start at around $1000 but I know for a fact that with them if you are inside 1000' without line of site and 5 miles with line of site you will get a rock solid connection. If this is an industrial application that requires a good connection to the PLC I would consider that option. Data-Linc Group's radios are the ones I'm thinking of but there are others out there just keep in mind that it is very much a "you get what you pay for" industry and sub $100 radios generally only work at a few hundred feet with line of site.
From what I've read so far (and I may have missed something) it sounds like you aren't making the connection to the WiFi router but even after you do there are going to be some challenges.
On one final note (for now), when/if you do get a connection all the way back to the PC, the "auto configure" feature in RSLinx will more than likely not work even though you have a path. Even though the comm port redirect software should be cleaning everything up, adding all of the overhead onto the DF-1 packets adds significant delays and latencies that the auto config feature doesn't like so don't rely on that to determine if you have a link.

So you are saying that I HAVE to use a wifi router to make this work? I would be using this in multiple factory floors where I will not have a wifi access point other than this converter device. Do I need one of these instead ?

http://www.usconverters.com/wireless-serial-adapter-ez50?zenid=4e1a51eb7bccba76d5c63c4081cdd2f5

The converter broadcasts its own SSID which I can connect to wirelessly and pull up the settings via GUI webpage

sjt · Dec 26, 2018

controlconcepts said:
One thing I also try with serial comms is to verify the settings through typing mode into a command prompt. This will also show if the com Port is in use. If it is open it will not show the com port. And if nothing has the comport open it will show all of the settings for that port. To me this is the most reliable way to see what the settings are. I've had plenty of situations with various ethernet to serial devices where settings don't get saved through a web browser or the manufacturer software. There have been times I even had to make the final comport settings through device manager. Hope this helps. Merry Christmas.

I will try this, thank you.

Firejo · Dec 26, 2018

I guess some clarification is in order. I assumed you were connecting an existing PC on a network to the SLC5/03 using an existing WiFi network. However, it sounds like you want to create an application where a laptop is making a direct connection to the SLC5/03 using WiFi. In the latter, then the unit will need to be an AP with your laptop being the SA (which laptops are). Then it comes down to the first step is still do determine that you have an RF (WiFi) connection between the laptop and the AP. If you are using a newer laptop the issue you are going to run into is the WiFi protocol used. The device you have only works in 802.11bgn (802.11b, 802,11g and 802.11n). Most current laptops will more than likely work with 802.11n, maybe 802.11g but more than likely not with 802.11b. Then you have the security issue. Your device has WPA2-PSK and I think most modern-day laptops still support that, but you may have to configure it specifically to connect to the WiFi adapter.
The next step will be to get the path working I.E. comm port redirect to actual comm port. UsConverters offers a tool called “Open AccessPort’s”. I would use that to run a loopback test. Once you have that working you will probably be able to make the connection however the auto config in RSLinx will still probably not work and you want to disable all handshaking lines on both ends.
If you are looking at being able to go on site with a laptop and connect to a serial PLC then I do understand the need for this type of device however it is still a complicated process. Having said that, once you get it setup the first-time is should be straight forward from there. One final note, if this is something that you want to install at customer sites, you are going to run into IT departments that probably won’t let you add another WiFi network in their facility.

sjt · Dec 26, 2018

Well wonders never cease. It works!!!! I'm embarrassed to post the solution but for the next guy(or woman) that comes along.....

The converter lists some optional accessories, one of them being a power supply, which I purchased. After looking at the webpage again, it didn't appear to come with a Fem to Fem cable which I didn't have either. So I ordered a cable and power supply with the unit. Well the unit DOES come with a cable but it was shorter than the one I ordered so I just left it in the box. Apparently not all serial cables are created equal or I received a bad cable. The unit works great and gets online just fine with the included cable.

Thank you everyone for your input(pun intended) !!

On a side note......the Auto-Configure works just fine when you have a good cable. I should have suspected that earlier but every day's a skool day.

Firejo · Dec 27, 2018

Good to hear and I am surprised the auto configure works. That does tell me that the product is doing a good job at bridging Ethernet to Serial and doing it without any significant "gaps" in the data stream.
Also, I wouldn't be embarrassed because you are correct, not all serial cables are created equal and you'd be surprised what some manufactures will do with the RS232 "standard". Having said that, when I look at their website, I noticed (now that you mentioned that the cable fixed the issue) that the device has a male DB9 connection as does a SLC. 9 times out of 10 that is going to mean you need a null cable which a serial cable that has the same gender on both ends usually is. However, the female to female cable they have on their website is a straight through cable so if that’s the one you ordered then that’s why it didn’t work (a few assumptions here). The cable that came with the device (clearly) is a Null cable (again, a few assumptions) which is what I would expect.
For those who don’t know a lot about serial ports, there are two types of RS232 ports (outside of different handshaking line configurations), DTE (Data Terminal Equipment) and DCE (Data Communications Equipment). DTE (if you use the standard and a db9 connector) uses a male connector and pin 2 is transmit and pin 3 is receive. DCE uses a female connector and pin 2 is receive and pin 3 is transmit (pin 5 is signal ground). That way a straight through cable, which should have a male connector on one and a female on the other, will connect pins 2 to 2 (DTE transmit to DCE receive) and 3 to 3 (you get the idea). So, if you have two DTE devices (or two DCE devices) then you need a cable or Null adaptor that crosses pins 2 and 3 and has either two male or female connectors. Having said all of that, the RS232 standard gets corrupted frequently so just because you have a device that is a communications device, or a terminal device does not always mean it will have the correct type of port on it. The same thing can be said about the gender of the port so sometimes you just have to “test” it or get a breakout box (or inline device) that uses LED’s to indicate what state the pins are at (high, off or low).
Anyway, sorry to highjack your thread but I figured it was a good opportunity to pass along some information that is not the norm anymore. Again, good to hear its working.

sjt · Dec 28, 2018

Firejo said:
Good to hear and I am surprised the auto configure works. That does tell me that the product is doing a good job at bridging Ethernet to Serial and doing it without any significant "gaps" in the data stream.
Also, I wouldn't be embarrassed because you are correct, not all serial cables are created equal and you'd be surprised what some manufactures will do with the RS232 "standard". Having said that, when I look at their website, I noticed (now that you mentioned that the cable fixed the issue) that the device has a male DB9 connection as does a SLC. 9 times out of 10 that is going to mean you need a null cable which a serial cable that has the same gender on both ends usually is. However, the female to female cable they have on their website is a straight through cable so if that’s the one you ordered then that’s why it didn’t work (a few assumptions here). The cable that came with the device (clearly) is a Null cable (again, a few assumptions) which is what I would expect.
For those who don’t know a lot about serial ports, there are two types of RS232 ports (outside of different handshaking line configurations), DTE (Data Terminal Equipment) and DCE (Data Communications Equipment). DTE (if you use the standard and a db9 connector) uses a male connector and pin 2 is transmit and pin 3 is receive. DCE uses a female connector and pin 2 is receive and pin 3 is transmit (pin 5 is signal ground). That way a straight through cable, which should have a male connector on one and a female on the other, will connect pins 2 to 2 (DTE transmit to DCE receive) and 3 to 3 (you get the idea). So, if you have two DTE devices (or two DCE devices) then you need a cable or Null adaptor that crosses pins 2 and 3 and has either two male or female connectors. Having said all of that, the RS232 standard gets corrupted frequently so just because you have a device that is a communications device, or a terminal device does not always mean it will have the correct type of port on it. The same thing can be said about the gender of the port so sometimes you just have to “test” it or get a breakout box (or inline device) that uses LED’s to indicate what state the pins are at (high, off or low).
Anyway, sorry to highjack your thread but I figured it was a good opportunity to pass along some information that is not the norm anymore. Again, good to hear its working.

Thanks for the info, I thought a serial cable was a serial cable was a serial cable. I'll never forget it now. Anyways, job complete, the device worked flawlessly and maintained a good connection from 75 ft away with lots of factory apparatus in the way. VERY helpful when troubleshooting I/O.

Thanks Everybody !

RS232 to WiFi converter

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