SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492024-03-29T09:20:48-06:00SparkFun ElectronicsLutorm on BOB-09822 - SparkFun USB to RS-485 ConverterLutormurn:uuid:0bf82d89-e09b-753a-1869-0c6942325ccb2019-02-09T20:24:42-07:00<p>Does anyone know what the delay of this converter is, ie what's the time between sending to the usb port and bits getting clocked out over the rs485? My application doesn't need a lot of bandwidth, but it is latency sensitive.</p>
Customer #558854 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #558854urn:uuid:cbf28880-c620-d263-2e9b-bfda2d1d52af2016-01-27T07:06:00-07:00<p>I bought 1 SparkFun FTDI Basic Breakout - 3.3V, 1 SparkFun Transceiver Breakout - RS-485 and 1 SparkFun USB to RS-485 Converter .<p>I connect:</p><p>PC1 -> FTDI Basic Breakout -> Transceiver -> USB to RS-485 -> PC2.</p><p>To communicate PC1 to PC2, I connect TXDEN (FTDI Basic Breakout ) to RE/DE (Transceiver). If I send "Hello PC2" message, in PC2 I receive " Hello PC2<0>".</p><p>To communicate PC2 to PC1, if I send "Hello PC1" message, in PC1 I receive " Hello PC1" but in PC2 I receive many bytes of trash. The same trash come if RS485 modules are not connected.</p><p>I suspect that SparkFun USB to RS-485 Converter is damaged, but its new...</p><p>Anyone else had this issue?</p></p>
Customer #731543 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #731543urn:uuid:e54c5128-3e7e-48cc-bb40-187dd5dc41352015-10-22T07:17:40-06:00<p>I have a set of Modbus RTU RS485 slave controllers. I need to read/write from/to these controllers using an application on a PC. would this converter do the job?</p>
Customer #731543 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #731543urn:uuid:1f1b961e-a30e-7331-4fde-5d8f2f0f668f2015-10-22T07:15:02-06:00<p>I have a set of slave controllers running on MODBUS RTU(RS-485). I need to read/write data from/to these controllers using a GUI on a PC. would this do the job?</p>
jma89 on BOB-09822 - SparkFun USB to RS-485 Converterjma89urn:uuid:928775f9-f902-04b0-44dc-4d581c85939d2015-03-17T13:43:48-06:00<p>You'll need something to talk USB on both sides, so yes, your remote device would need to be a USB host and have the proper drivers for talking with this chip.<p>Is this temperature box pre-purchased or something you built? There are other options for doing USB over vast distances (active extenders, Ethernet (as in IP) adapters, etc), but they each have their pros and cons.</p></p>
Customer #662492 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #662492urn:uuid:093a8c63-b108-79f4-b4a5-66d0785d40782015-03-17T13:38:05-06:00<p>Can this work at both ends - I have a simple USB temperature box that connects to a computer. I need to run this over a long distance so would like to go from USB to rs-485 and back to USB. I'm not sure if this board will work without a computer and kernel driver</p>
Customer #630412 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #630412urn:uuid:2044846f-b3aa-b057-7219-0889569584cf2014-12-23T11:48:17-07:00<p>I just got the newer 09822 board and pretty much works out of the box for QLC+ ( Q Light Controller plus) software. The terminating resistor on the board is 220 ohm. I added a 220 ohm resister in parallel across A and B to get the approximate DMX termination value of 110 ohm. I soldered the resistor between pins 7 and 8 on the RJ45 connector holes. I used the FTDI CDM drivers on Windows XP. QLC+ detected the board and once you map it as output in your DMX universe, the red LED starts flashing. For all intents and purposes, this board should look like an OpenDMX interface. Lights go on and off and dim as expected in QLC+.</p>
Customer #617202 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #617202urn:uuid:44d465f9-a1d6-066a-dd73-d9826241e1292014-11-17T21:50:27-07:00<p>Sorry for comment on an old comment, hopefully you'll see this. Did you have to do any of the reprogramming that these comments mention in order for this to work with DMX? Or did it just work out of the box for you?</p>
Customer #203383 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #203383urn:uuid:4d4f1244-99d2-1069-b178-bf0f34ea946d2014-11-14T09:20:27-07:00<p>Ive build a small housing for this adapter:
http://www.thingiverse.com/thing:540898<p>Greetings Klaus</p></p>
Customer #359298 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #359298urn:uuid:b387ee6a-9d9d-4624-1ba4-7a2f9a9051df2014-08-09T20:23:53-06:00<p>The description above is a bit misleading. It seems to imply you can use this device up to 10 MHz baud rate (i needed 6 MHz). After a bit of digging I discovered the FTDI chip only goes to 3 MHz baud rate. I guess the comment is about the RS484 converter part only.<p>Sparkfun, you really should fix the wording in the description since we now have a half a dozen of these laying around with no home.</p></p>
Oronymo on BOB-09822 - SparkFun USB to RS-485 ConverterOronymourn:uuid:6314373b-158b-7ba1-bd05-f562f48943862014-05-23T10:17:27-06:00<p>I'm considering using this to control the MondoMatrix which is basically a multi-motor version of an Arduino board that communicates via RS-485. I'm wondering what an appropriate programming environment / application on Windows might be for controlling via this device?</p>
Customer #523560 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #523560urn:uuid:b351bcc0-7693-af7d-443b-48bbb6c9f7022014-02-22T05:37:50-07:00<p>can someone tell me where can I find this in the Sparkfun Eagle libraries ????</p>
Matthew Currie on BOB-09822 - SparkFun USB to RS-485 ConverterMatthew Currieurn:uuid:4ba4f8a0-e1f1-f635-a39a-9a46c983c6822013-12-31T13:20:21-07:00<p>Read for quick and easy fixes! My adapter did not work correctly out of the box. The <em>TX and RX LEDs are reversed</em> as I would expect to see TX LED pulse when sending data to the 485 bus. The <em>CTS# line is unconnected</em> and therefore internally pulled high. The CTS line being high prevents the UART from sending data as the CTS line is the counterpart for RTS/CTS flow control. You could solder pin 11 to ground or better yet, I recommend users perform the following EEPROM change to the FT232RL using the FTDI FT_Prog utility (http://www.ftdichip.com/Support/Utilities.htm).<ul>
<li>Plug USB to 485 adapter in</li>
<li>Devices -> Scan and Parse (Ensure you have the correct device if you have a number connected. If in doubt, disconnect others)</li>
<li>FT EEPROM -> Hardware Specific -> Invert RS232 Signals -> (check) Invert CTS#</li>
<li>FT EEPROM -> Hardware Specific -> IO Controls -> C0 (select) RXLED#</li>
<li>FT EEPROM -> Hardware Specific -> IO Controls -> C1 (select) TXLED#</li>
<li>Devices -> Program</li>
<li>Cycle the USB device (unplug and re-plug)</li>
</ul><p>Select Hardware Flow Control (RTS/CTS) in your favorite program or library and away you go!</p></p>
pratikshinde on BOB-09822 - SparkFun USB to RS-485 Converterpratikshindeurn:uuid:a163fe21-1e8e-e78c-5071-88c4a2e930902013-10-08T06:43:43-06:00<blockquote>
<p>The RTS pin of the FT232RL is connected to the transmit and receive enable inputs of the SP3485</p>
<p>However schematic shows, TXDEN is connected to RE and DE. Which is correct?</p></blockquote>
tantivy on BOB-09822 - SparkFun USB to RS-485 Convertertantivyurn:uuid:a1658fda-51d6-07b9-0cd0-af47fdddc1c32013-09-16T08:30:11-06:00<p>One suggestion I have is to bring pins 4/5 on the "RJ45" (don't get me started about incorrect use of RJ nomenclature) out to JP12, and put ground pads adjacent to them. That way you can easily use the third pair for other things if you don't need the ground, or jumper across if you do. Maybe add pads for the shield of a shielded "RJ45" while you are at it. The same comment would apply to BOB-10124.</p>
adamj537 on BOB-09822 - SparkFun USB to RS-485 Converteradamj537urn:uuid:238180ee-d1a7-e5b0-72bc-0fbc69f2cdee2013-09-09T14:12:22-06:00<p>Kudos to you for replying to a two-year old comment! I meant my remarks as sort of a clarification to others who read comments (and didn't realize there was a customer involved who would dictate communication methods). Perhaps you're right about the jumper.</p>
Skye on BOB-09822 - SparkFun USB to RS-485 ConverterSkyeurn:uuid:6ca8883c-fa45-d19a-e330-221b734e88b22013-09-06T13:47:49-06:00<p>I suppose this is a matter of taste, but most systems that use RS-485 in the military world use it because it allows for a multidrop system with limited number of wires. In such systems it is important/critical to know if you have had a bus collision. For this reason, the receiver is always left on. When you transmit, you read back what you wrote. If they are the same, great; if not, you had a collision and must rebroadcast. Very similar to Ethernet.<p>If in the commercial world RS-485 is only used for single duplex single master to slave setups then their implementation is fine. Otherwise I contend they have their heads in a dark place.</p><p>Not that Sparkfun reads these comments (its been two YEARS since I posted), but if they do, I would suggest the next revision of the board include a solder jumper to allow for a "receiver always on" mode. By default it would connect the /RE and DE as right now. Add or remove the solder jumper and the recieve enable would be enabled and the transmit enable would go back to the micro. Should only add the cost of one resistor and a bit more copper.</p><p>As for considereing other options, I would love to, but I am dictated by my customer. Its been a while, but I think I was able to lift the receiver enable pin and tie it appropriately.</p></p>
adamj537 on BOB-09822 - SparkFun USB to RS-485 Converteradamj537urn:uuid:f55565f6-5e4a-81ea-2ff8-b739e5761f832013-09-06T13:11:10-06:00<p>Most commercial USB-to-RS-485 adapters are built with the /RE and DE connected, since RS-485 is half-duplex (you can either send or receive, but never both at the same time). This allows a single pin of a microcontroller (or the TXDEN pin of an FTDI chip) to control both receive and transmit enables at the same time. Wiring the adapter so both the transmitter and receiver are enabled at the same time will cause any characters transmitted to be "echoed" back, which is only desirable for custom applications where software can distinguish between an echo and a response from another device.<p>If bus contention is an issue, try using a protocol where each device has a unique address, a "master" device transmits to the other "slave" devices, and then each slave transmits after a fixed time interval multiplied by their address...so no one talks at the same time. If you truly need full duplex communication, consider using two RS-485 transceivers (and four wires).</p></p>
Alexander Donohue on BOB-09822 - SparkFun USB to RS-485 ConverterAlexander Donohueurn:uuid:432527c8-ae1e-46f2-64c7-787d8017493a2012-12-10T22:43:49-07:00<p>Really late reply, I hope you got your issue fixed. I figured that this may be of some use to others. I am using this for my lighting system.
I am using Q Light Controller (http://qlc.sourceforge.net/)
This board is functionally the same as the ENTTEC Open DMX USB Interface. In fact I use the same drivers with the board. They are available on the ENTTEC website under Downloads->'Drivers Setup' (http://www.enttec.com/index.php?main_menu=Products&pn=70303&show=downloads)</p>
mitchmao on BOB-09822 - SparkFun USB to RS-485 Convertermitchmaourn:uuid:adac666d-e7af-f447-8c81-748a0b19e57b2012-04-19T10:34:03-06:00<p>I was planning to use this for OpenDMX application as the new Arduino UNO ditched the FT232 chip. Where you able to get the thing to work? Contact appreciated =)</p>
Skye on BOB-09822 - SparkFun USB to RS-485 ConverterSkyeurn:uuid:31fc5eb3-15a2-431e-ce1a-0f08507f50762011-08-29T08:23:38-06:00<p>/RE and DE should not be connected. If they are it is NOT possible to perform bus contention testing on a multidrop system. If two transmitters were to send at the same time, the only way they know if there was a collision is to read back what they sent to make sure they are the same. The way you have it implemented, enabling the transmitter disables the receiver! I hope I can modify the board to always enable the receiver, if not, it will have to be returned.</p>
Big Daddy Mike on BOB-09822 - SparkFun USB to RS-485 ConverterBig Daddy Mikeurn:uuid:63e2768e-e066-068d-ed39-b40a1f1e29502011-08-17T23:16:43-06:00<p>I got mine today and they worked fine once I swapped A & B on the RS 485 end. The Rx and Tx lights are also backwards for my application.</p>
Customer #233818 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #233818urn:uuid:45088f10-908b-ed65-d11a-22a304d1c1ac2011-06-22T01:10:50-06:00<p>I need more throughput than this chip will provide. That is, Larger TX and RX buffers on the chip. Anyone know where I can get a USB to RS485 converter with a larger buffer?</p>
Cyphus on BOB-09822 - SparkFun USB to RS-485 ConverterCyphusurn:uuid:f30c4652-4fc5-78fc-c279-a33770e1d6842011-05-14T13:16:18-06:00<p>Has anyone else managed to get this to work for DMX-512? I have it set up with openDMX controller software, but the very second I hook it into the DMX system it causes a blackout.<br>
This board seems to have the same circuits as many others online (except for some protection circuits missing) and I see no reason why it shouldn't work.</p>
Customer #62690 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #62690urn:uuid:6eaa6efb-252b-6abf-c7a3-90054f68df822011-02-11T23:49:43-07:00<p>Yeah I agree TX & RX are swapped.</p>
c.fowler on BOB-09822 - SparkFun USB to RS-485 Converterc.fowlerurn:uuid:51f4cbcf-5276-8fa2-f1a0-3d781367901b2011-02-06T15:46:01-07:00<p>1a: Fixed termination resistor is a bad idea.<br>
1b: The termination resistor is the wrong (common) value.<br>
2: DE should be tied to TXDEN!<br>
3: Don't tie /RE to DE on the SP3485. (Some of us like to hear what we say...)<br>
I can't believe all the RS485 break-outs (at the time of writing this) suffer from 1 and 3...</p>
Customer #27638 on BOB-09822 - SparkFun USB to RS-485 ConverterCustomer #27638urn:uuid:bb094ecf-9eea-4ed1-0fa8-c8dd261e5e4d2011-01-25T17:52:03-07:00<p>Correct me if I'm wrong, but the TX and RX markings seem to be mixed up on the Silk screen on the newest version (BOB-09822)?<br>
Other than that its a nice little board. Just started using it with PySerial :)<br>
Cheers!</p>
bikeNomad on BOB-09822 - SparkFun USB to RS-485 ConverterbikeNomadurn:uuid:f3e406d7-193b-4522-2f68-e36bffc138572010-12-20T21:14:57-07:00<p>The description above<blockquote>
<p>Driver/Receiver Enable connected to RTS line of FT232RL<br>
is incorrect; the enables are in fact connected to one of the GPIO lines of the FT232RL (pin 13, CBUS2/TXDEN).<br>
This is what most people want; it means that you don't need special application-layer support for turning on RTS to transmit.<br>
If you have an application that insists on turning on RTS it should also work fine.</p>
</blockquote></p>
dlbsmith on BOB-09822 - SparkFun USB to RS-485 Converterdlbsmithurn:uuid:2ac1fb00-42cc-92c9-a2dd-4045fcbb502c2010-09-26T15:36:59-06:00<p>Has anyone tried to connect one of these to the RS-485 Breakout sku: BOB-09823?<br>
I have an RS-485 Breakout connected to a Fez Domino and I am trying to communicate through RS-485 to a PC.<br>
We have scoped out the RS-485 line and transmitted data in both directions looks fine.<br>
If we connect a different RS-485 device from a different manufacturer then we can communicate to it in both directions.<br>
So the issue seems to be communicating between two SP3485 based devices.<br>
We have tried adding additional bias resisters similar to those on the other device. But it does not help.<br>
Our best guess is that the issue is related to the 3.3V operation and the fact that each one has a terminating resister. Since an RS-485 network should really not have multiple termination resisters we wonder if this is the problem. Before I start modifying a board I wanted to see if anyone else had sucess with this setup.<br>
As a product suggestion: a switch or jumper to disconnect the termination resister.</p>
Cory78 on BOB-09822 - SparkFun USB to RS-485 ConverterCory78urn:uuid:0392a86b-a596-506b-a97c-dbdee361ed8a2010-09-02T18:44:38-06:00<p>But you didn't fix the description describing your change... just cost me many hours of time :(<br>
"Driver/Receiver Enable connected to RTS line of FT232RL"</p>
AaronCarlton on BOB-09822 - SparkFun USB to RS-485 ConverterAaronCarltonurn:uuid:61619738-09b0-0737-da00-ba59aa2cd7be2010-06-29T09:56:50-06:00<p>Fixed!</p>
AaronCarlton on BOB-09822 - SparkFun USB to RS-485 ConverterAaronCarltonurn:uuid:0f081a00-f0ae-413e-387f-56d71a7527682010-06-24T12:36:06-06:00<p>Schematic PDF and Eagle files are for RS485 driver board, not the USB to rs485 converter board. (FTDI Chip is not in the schematic, but is on the board in the picture)</p>
RobertC. on BOB-09822 - SparkFun USB to RS-485 ConverterRobertC.urn:uuid:e73fc5b5-0258-b16c-ab4e-c971b9c7e2832010-06-16T13:29:52-06:00<p>Sorry about that! Fixed.</p>
electrokean on BOB-09822 - SparkFun USB to RS-485 Converterelectrokeanurn:uuid:f2dec276-5b08-cc18-a84c-f0983d81ca9b2010-06-10T17:46:04-06:00<p>So does this version use RTS or the FTDI TXDEN signal to enable the SP3485 driver ?<br>
The schematic seems to still be for the original version of the board.</p>