Ren-W Questions/Answers

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  • Can a Ren-W be connected directly to the computer?
  • Yes, although because the Ren-W was designed as a plug-in adapter for the Renard SS controller which outputs RS-485 data on pin 5 of its J1 jack, an RS-485 signal is required instead of RS-232. Use an inexpensive RS-232/RS-485 converter and the standard Renard SS wiring scheme (pin 5 is + data, pins 1-2 are ground, pin 4 is unused by Ren-W’s J1) and plug it into the Ren-W’s J1 jack. By the way, the Ren-W at a computer would be in XBee transmit only mode since there is no receiving to be done by the computer and the board would require only a single XBee module. (Note: a direct RS-232 connection generally provides more voltage than the Ren-W can accommodate and usually causes an XBee module to stop functioning very quickly.)


  • Can the Ren-W be used with a USB RS-232 to RS-485 converter?
  • Yes, as long as you use the RS-485 cable wiring specification for Renard SS controllers. (Pin 5 is data, pins 1,2 are ground, pin 4 is unused by Ren-W).


  • Can the Ren-W be powered independently instead of powered by the SS board?
  • Yes. Connect +5vdv to either pin of the JP3 header and ground (-) to either pin of the JP4 header. Do not use a power supply that provides more than +5vdc and never connect JP3 to JP4! (Note: the Ren-W's voltage regulator should not become hot during normal use. Ren-W has been tested with a 12vdc supply and the regulator gets quite warm when powered this way. If you must power the Ren-W with 12vdc, consider attaching a heat sink to the back of the U1 voltage regulator.)


  • What kind of current draw does a Ren-W have?
  • More current is used when an XBee module is transmitting than receiving. The higher-powered XBee Pro module requires upwards of 290ma while the standard XBee module requires only about 50ma. The 3.3vdc voltage regulator on the Ren-W is rated up to 500ma. Because the Ren-W draws its +5v power directly from the Renard SS controller, Ren-W users who experience inconsistent or erratic transmission performance may consider replacing the SS controller’s LF50CV ½-amp voltage regulator (Mouser # 511-LF50CV) with an LF50CP instead ( # 511-LF50CP), which has a full 1A capacity.


  • Does cat5 cable length matter when connecting a Ren-W to an SS controller?
  • Both RS-232 and RS-485 are pretty robust and with RS-485, long cable lengths (up to 1000’) are certainly possible. We’ve tested it with 100’ cable without a problem but as the basic concept of Ren-W was to eliminate cables, keep them as short as possible anyway.


  • Can I mix Global Broadcast mode with PTP mode?
  • Theoretically yes, if you’re very clever with using combinations of the XBee’s PAN ID and addressing configurations and don’t mind experimenting to see what works best for you.


  • Can I mix SS8, SS16 and SS24 boards in the same Ren-W network?
  • Yes. In PTP mode, they will function just as if they were connected via cat5 cable. In global broadcast mode where each Ren-W receives the same commands instead of only those passed on from the previous controller, results may vary. Re-read the “Renard basics and how they relate to Ren-W” section on the first page of the Ren-W Wiki.


  • Can I mix hardwired SS controllers with Ren-W wireless controllers?
  • Yes, Ren-W was designed to be an easy add-on to an existing wired system in either or both global broadcast, PTP or alternate PTP broadcast modes.


  • Can I use a Ren-W with my Ren-C/595 or Ren-C/Grinch controllers?
  • Yes. It works very well when the RS-OUT of the Ren-C is plugged into the Ren-W's input for transmitting the signal out to the network. However, when the Ren-W is to control the Ren-C/595 or Grinch, it is necessary to also use a snap choke core balun on the cat5 cable going into the Ren-C's RS-IN jack (Radio Shack part# 273-0069). The balun eliminates EMI/RFI interference generated in the cat5 cable that's caused by the XBee radio module. Without the balun, the Ren-C will likely encounter framing errors and will not communicate with the Ren-W. Power for the Ren-W can be tapped from the 595/Grinch +5v header pins, from the Ren-C’s vcc header pin immediately to the left of the 2N3904 transistor (Q1) or from the Ren-C’s vcc header pin of the JP6 PGM row (2nd pin from the top). Note that the ZC signal must be supplied to the Ren-C directly and cannot be passed along wirelessly by the Ren-W. The Ren-C’s RS-485 RS-OUT serial signal is approximately 4.52vdc, which is still within the acceptable range that Ren-W can accommodate.


  • Do I always need two XBee modules on a repeater board?
  • Yes and no – it depends on whether the Ren-W is serving as a normal repeater or whether you want it to be an E-mode repeater. The normal repeater board uses two XBee modules, one for receiving and the other for transmitting. The E-mode repeater uses only one XBee module which performs both receiving and transmitting functions. Other than the obvious price difference between the two types of repeater boards because of the added XBee module, it’s important to understand that there may also be a performance difference because a single XBee module can’t perform receiving and transmitting simultaneously. It’s important to note that the design of the Ren-W allows switching from E-mode to normal mode by simply disconnecting the jumper shunt on JP5 and of course, adding and configuring the second XBee module. So one can always start with the E-mode repeater and if a performance lag is encountered, you can always switch to normal mode without having to take out the soldering iron.


  • How can I use “global broadcast” mode yet have each Renard controller respond to its own range of Vixen channels?
  • You can’t because the current version of the Renard plugin and firmware does not provide for a way to assign a specific address to a controller. It's certainly possible to revise the Renard firmware in some fashion to make a specific controller sensitive to only a specific range of channels, but there currently is no plan to release such a feature because of the apparent difficulty in explaining, configuring and maintaining it. However, if some form of internal Renard addressing is ever released, it probably would allow the Global Broadcasting mode to be used in a controller-selective fashion. The main Ren-W transmitter would merely send all channel information out to all Ren-W receivers simultaneously and each Renard controller’s customized firmware would perform the task of picking out only the channels that it’s supposed to use and thus eliminate virtually all cat5 wiring between Renard controllers. HOWEVER... if you get a little creative you can simulate this to some degree. For example, if you used three 24-channel controllers and set up each of their Ren-W receivers so that all three received the same "broadcast" signal, you could connect lights to only channels 1-8 of the first controller (leaving channels 9-24 unused), channels 9-16 of the second controller and 17-24 of the third controller to simulate "broadcast addressing."


  • Can the Ren-W work with other Renard controllers such as the Renard 16, Renard 24 or Renard 64?
  • Possibly, but some of those boards have different design versions and the RJ45 serial pin outs as well as the serial signal may vary from the Renard SS board’s design. The Ren-W was originally designed to be a plug-in option for WayneJ's Renard SS controllers but it has been successfully tested with fkostyun's Ren24 version 3.0 and 3.3. If the RJ45 pinouts are the same as the Renard standard, it should work. However, if the pinouts are different from the Renard standard, you would have to make your own custom cat5 connection cables to connect the Ren-W to the Renard board instead of using the standard, straight-through cat5 cabling scheme. It is also possible that the use of the choke core balun (as for the Ren-C adapter) may be required.


  • Will the Ren-W work with DMX?
  • Probably not, because DMX usually requires a higher throughput than the XBee’s maximum. An XBee is limited to 115,200 and was designed to accommodate streaming data only up to 80kbps. DMX’s communication need is normally higher than that. But you could certainly give it a go – the Ren-W simply transfers a serial signal from one place to another. You’ll obviously have to consider the connector pin outs used for DMX and you may end up creating your own connection cables to/from the Ren-W to/from your DMX setup, but a completed pair of Ren-W boards are relatively inexpensive to make so the cost of experimentation isn’t very great.


  • Can a Ren-W be used with other light controllers or other devices to create a wireless connection?
  • Maybe. Remember, Ren-W is essentially a wireless serial connection which means that theoretically, it could connect most any serial devices because it’s essentially transparent to the two devices involved – it merely inputs a serial data packet on the transmitting Ren-W’s J1 connector, translates it into a TTL data stream and transmits it to another Ren-W where the data stream is recombined into the serial data packet and output via the receiving Ren-W’s J2 connector. Because it’s a serial device, remember that the serial communication parameters (8 data bits, no parity, no stop in the case of the Renard controllers) can be changed to match a different packet structure such as 7 data bits, even parity, an 1 stop and that such configuration is done inside the XBee modules using the XCTU software. Obviously the transmitting and receiving units must be configured with the same communication parameters so that the serial data at the receiving Ren-W’s output port J2 is in the same format as it was originally when it went into the transmitting Ren-W. Another consideration is that an XBee’s maximum transmission speed is 115,200 bps but is really rated at only 80kbps in continuous, streaming data situations which may or may not be adequate in every case.


  • Will the super-powered 900mhz XBee radio modules work for even greater range?
  • Maybe. Some radios in the XBee line supposedly provide a line-of-sight range of up to 12 miles, but they may not have the same speed throughput capability that you may need and their electrical power requirements may be greater than are designed into the Ren-W board. The concept still is sound, but they may not be a drop-in replacement for the current Ren-W design.


  • Is a Programmer Board a necessity or can I get by without one?
  • It's not terribly difficult to program an XBee using the Ren-W board and information about doing that is included in the configuration section of the Ren-W wiki pages. However, the programmer board is well worth the purchase and provides for duplex communication with the XBee radio, as well as a way to test modules, test communication, test settings, etc. before putting the units in the field. It can also be used as the originator transmitting module and Vixen can easily be configured to use it. So yes, you can 'get by' but like having a Pic programmer if you use Renard, having an XBee programmer can be just as beneficial.


  • Will a version of Ren-W be available for parallel port controllers?
  • No, there are no plans to create a parallel port version. Parallel port-based technology has rapidly lost popularity over the past few years and many computer manufacturers no longer even include parallel ports on their products. However, you could certainly try using a parallel-to-serial converter at the computer end, feed the resulting serial signal into J1 of the transmitting Ren-W and at the receiving Ren-W’s J2 jack, use a serial-to-parallel converter to convert it back into the parallel signal you need. Whether this will actually work is unknown; in theory it sounds like it might work but in actual practice, it may not. And remember, Ren-W uses RS-485 input into its J1 jack, not RS-232!


  • What kind of wireless range can I expect to get?
  • Even though the XBee radio’s specifications indicate much longer distances, in actual practice, a regular XBee module should provide roughly 50-75’ range while the XBee Pro module can generally work up to 175’. Greater distances are possible, but signal reliability is a major issue when the radios are operating at 57,600 baud, the basic speed that is recommended for Renard SS controllers. Note that you should also expect to experience occasional light flickering or even miscued lights that are caused by data dropouts, a common occurrence with high speed wireless serial connections that use streaming data without a hardware or software flow control mechanism. If the SMA version of the XBee Pro module is used with an efficient external antenna, one might experience incredible range, potentially upwards of several miles line-of-sight. However, extreme distances such as this have not been tested as they seem outside the scope of intended use.


  • I’m concerned about dropped data. How might it affect my light show?
  • In testing, the range of dropped bytes was in the neighborhood of .014 to .044%, equivalent to between 14 - 44 bytes out of every hundred thousand bytes transmitted. A typical song of 2½ minutes’ duration with moderate lighting commands for an SS24 controller might result in about 60K of Renard control data using 50ms timing in Vixen sequencing software. Applying the percentage formula, that could result in 8 to 26 dropped bytes; at one byte per cell, that’s equivalent to 8 to 26 cells over the course of the entire song. It could appear as a light that’s one cell (50ms) late in turning on or off, or if the byte represents a cell that’s in the middle of a long ramp up or down (4 or 5 seconds), one or two very slight flickers. In most cases, viewers probably wouldn’t even notice them.


  • Can you make it so no bytes are dropped at all?
  • No, as this would require the use of flow control which, in a fast-paced streaming protocol that is often synchronized to a music track, tends to slow things down and data may eventually become out of sync with the music. The current Renard protocol assumes a direct wired connection, but it includes a space bit which is intended to help solve possible data flow issues and timing. There is no functionality built into the Renard’s PIC code for either software or hardware flow. Something you can try is to change Vixen’s Renard plug-in setting to use 2 stop bits instead of the normal one stop bit and see if that makes a difference for you. Of course, the stronger the radio signal is, the more likely fewer dropped bytes. Consider upgrading to the XBee Pro module if using the standard one, or possibly an SMA version and an external antenna.


  • Why won’t RS-232 input work?
  • Because Ren-W was designed for the Renard SS controllers and the SS’s J1 jack provides the lower voltage RS-485 signal, the Ren-W does not include circuitry that will properly and consistently work with RS-232 input. RS-232 input circuitry may be added at a later date.


  • Can I mount the Ren-W inside one of my waterproof broadband-type controller boxes?
  • Yes, but keep the XBee’s antenna away from the Renard SS’s transformer for best performance. Also understand that the more impediments you place between the transmitting and receiving antennas the less workable distance you’ll get. Lastly, if you decide to mount the Ren-W on the inside top cover of your broadband case, consider using the side-entry RJ-45 jacks and a little longer cat5 cable instead of the top-entry version and a shorter cable. This will reduce stress on the cat5 connectors on both the Ren-W and the controller.


  • Can I modify the design on my own and improve it?
  • Absolutely -- that’s in the truest spirit of DIYC! Remember also that you must then provide your design to other DIYC members without charge so that they may benefit from it, too. As a practical design suggestion, you’ll notice that the solder pads for XBee headers H1-H4 are elongated. The larger pads provide for a better home-etched board because otherwise, the tiny 2mm solder pads may be too small for enough solder to hold the headers to the board.


  • Where can I get more information about XBee radios?
  • Contact www.digi.com, makers of the XBee line. Their technical support staff is responsive, knowledgeable and courteous. There are also links to user forums on the digi web site and the discussions there are quite timely and helpful.


Additional Ren-W Links