Common WBo2 Problems & Solutions

RS232 - Debugging WBo2 - PC connections

Tech Edge wideband and display units use an RS232 serial protocol for unit-to-unit and unit-to-PC communication. This page tells you how to diagnose and solve RS232 and communications problems.

Symptoms of bad communications include not being able to use logging software ("Unable to connect" messages, etc.) or Tech Edge utility software where the status line show "TIMEOUT". Most problems are simply solved, and can be broken into 4 main areas described below. But, first :

  • Check no other software is using the serial port. A serial port cannot be shared between applications. If you have other equipment that uses the same serial port then make sure that software is not running when you run WButil. Use Task Manager to ensure other programs have been closed.
  • Check the RJ45 pins on the connector have not become "stuck". We have seen a couple of examples where the spring loaded pins in the grey/black RJ45 socket (not the clear plug) get stuck mechanically latched up and can't contact the pins of the clear mating plug. Visually inspect the socket (or swap to another RJ45 socket if your unit has more than one).

Here's a more comprehensive check list, after you have checked the above items :

  1. Dead Unit : Surprisingly, may problems that are claimed to be communications problem, have a more fundamental cause. Make sure your WBo2 unit's diagnostic LED(s) are working properly (each unit may be slightly different, so refer to your unit's specific on-line documentation). The status LED does NOT show RS232 faults, but if the WBo2 unit is not correctly going through its normal warmup sequence (15-30 seconds to heat the sensor to operating temp) with a known good sensor connected, then solve these issues first. Remember, WBo2 units require up to 3 Amps at a minimum of 10.5 Volts during warmup, and failure to provide this level of power can result in many problems.
  2. PC serial port problem : You need a functioning RS232 port (with DB9 connector). If you have just a USB port, then you'll need a USB to RS232 adaptor from either us or elsewhere Most current USB-RS232 adaptors are quite reliable, but avoid trying to use an older adaptor as some early ones had firmware bugs. The easiest way to simply check a USB adaptor is a simple RS232 loop-back test (described below) that uses WButil's terminal screen to get a typed character to be echoed back on the screen.
  3. Software setup problem : Ensure you have followed the instructions to use the software! Tech Edge software automatically sets the port (parameters to 19,200 baud, 8 bit, 2 stop bits). WButil's terminal screen has a status indicator at the bottom left of the application that shows the status of the connection. Note that this will show TIMEOUT if the [?] button is pressed and the serial connection is not working.
  4. DB9 to RJ45 adaptor problems: The Tech Edge supplied DB9 to RJ45 adaptor cable is usually very reliable unless physically damaged. Some of these cables were quite short, others longer, and some even have moulded DB9 plug ends. First check for any obvious physical damage, and either repair or replace as appropriate. See the tips to check, debug, and fix it, below. You can see the cable uses only two wires and a shield to connect the clear plastic RJ45 plug (Y1 plug and Y1 socket below) to the metal/plastic DB9 connector.
  5. WBo2 RS232 problems: Diagnostic steps so solve simple problems are covered below. Sometimes RS232 problems are caused by the RS232 driver chip (an ST202 or HIN202) getting zapped, but other WBo2 problems can cause similar symptoms. If you have a 2Y DIY model, make sure you have read the Errata section and applied all required fixes.
  6. Don't Reflash - solve the problem first! Reflashing (and rescue-reflashing) relies on a good RS232 connection. Trying to reflash a WBo2 unit to solve an RS232 problem is doomed to failure! Some problems that look like RS232 problems CAN be fixed with a rescue reflash - but these are rare. Most rescue reflash operations will fix errors when the normal reflash failed (because the wrong HXF file was used or the operation was interrupted), but a rescue reflash is a last ditch attempt to fix a unit, not a normal reflash operation.

Debugging DB9 to RJ45 cables - Loop-back Test

The schematic at right is for the DB9 to RJ45 adaptor cable used on WBo2 units starting with version 2. Note that although the WBo2 unit uses an RJ45 connector, the port is NOT compatible with Ethernet networks and is simply a convenient and readily available multi point connector we use. Do not use an RS232 cable designed for other equipment, or Ethernet cables with RJ45 plugs.

Follow this procedure to find where "RS232 is broken":

  • A. We recommend you use one of the Tech Edge utilities like WButil Terminal. Firstly note that windows software cannot share COM ports used by other programs. The COM ports shown on WButil's General Tab are COM ports not being used by other programs. If another application has grabbed the COM port you should be using, then you'll have to close that other program. You then should be able to select the COM port you need to use (clicking on the COM port select [down-arrow] button scans for new COM ports automatically). If you're unsure of the COM port you'll have to try them one by one as follows. Note: make sure you connect the WB unit (or power the WB unit up) AFTER you have booted your PC. This is because Windows may try to auto detects a serial mouse, and the default
  • B. Select the COM port to try from WButil's drop down menu under the General tab. Go to the Terminal tab.
    1. check the [√]Keep Text? option.
    2. check the [√]Auto CLS? option.
    3. uncheck the [ ] [History]? option.
    4. On the unlabelled drop down menu, select [No Translation]
    Now, when you typed into the Cmd: box, and press the ENTER key, that text will be sent out on the RS232 line. If there is an electrical loop back, the character(s) type will be sent back and received. WButil will display them in the large text area. Note that if Keep Text? was checked then to generate text data, simply type [ENTER] while the cursor is in the Cmd: area, and your existing text will be sent.

    First, to test that you have selected the correct COM port, you create a loop back on the PC's DB9 connector (or the PC's USB to serial adaptor's DB9 connector). Use a small screwdriver to short between pins 2 and 3 of the male DB9 - that is, the COM port from your PC (see image at right). Make sure you don't short to the metal connector shell . (for the purist: you could make up a short piece Of wire with two minifit terminals covered with heatshrink).

    Remember that you should NOT accidently short pins 2 & 3 to the metal shell of the DB9 as this will short the drive signal to GND. It may be easier, if you have a spare unsoldered DB9 female (ie. a mating) connector - plug it into the COM port (male) DB9 connector and then it easier to short pins 2 & 3 together and there is no metal surround.
  • C. When you get characters echoing then you know your PC's COM port is working at the most basic level - go to F below. Remember, as noted above, you do NOT have to set the COM port parameters under your operating system as WButil sets them on-the-fly. If you do not have male pins on the DB9 (but rather female socket holes), then you may be using the wrong connector - some PCs use something like a O|0|O||O symbol to identify the COM port.

    Another possibility is you have a cable or other adaptor between the COM port (typically at the back or your PC) and where you are connecting to it - this adaptor must be female-to-male, one-to-one, and straight-through, but you only need to have pins 2, 3, and 5 connected (so your adaptor cable is 2-2, 3-3, & 5-5 with one male plug end and another female socket end). A typical extension adaptor cable is shown at right.
  • D. If you are "sure" your COM port is working but cannot get it to echo, then something is still amiss! You must get characters to echo before moving to the next step. Check you are
    1. are you using the right physical port?
    2. selecting the correct port from the drop down menu?
    3. Shorting pins 2 and 3 (they are the second and third from the left on the top row of the MALE plug.)?
    4. Are you shorting either 2 or 3 to GND (don't!)?
    5. Do you have another application using the COM port you think is free.
    6. The least likely scenario is a bad COM port, but this is possible, so see next step!
  • E. As a last resort you should try an application and physical device you know should work on your COM port. Perhaps this is the first step in checking the COM port, but if all else fails ... Another option is to use a USB to serial adaptor, but these have their own set of possible issues. But if you have one, then try it out! Simply go back to step A above but note that when you plug in a USB-to-serial adaptor, you should see that there's now another COM port in WButil's drop down menu.
  • F. Lets assume you got characters to echo at step B. Now we have to make sure the DB9 to RJ45 adaptor cable, that came with your wideband controller, is doing the job properly.

    The first cable schematic shows that the Tech Edge supplied cable swaps pins 2 and 3, and connects 5 to 5. To loop-back, simply connect a wire between pins 2 and 3 on the RJ45 and see if you can get character echoes. OK! Easier said than done - try two single edged razor blades held together at one end, with the blades resting on pins 2 and 3 as shown in the image. If no luck then make sure that when looking at the RJ45 clear plug, pin 2 has the red wire, and pin 3 has the white wire, and that you are connecting to those two pins. If no luck then use a multi-meter (or other low current device) to measure continuity between pin 3 on the DB9 to pin 2 on the RJ45, and from pin 2 on the DB9 to pin 3 on the RJ45, as well as pins 5 to 5.
  • G. If you do get echo at the previous step make sure you don't get an echo when you now take the wire (or razor blades) away. This ensures there's not an inbuilt short that can prevent comms from happening.
  • H. At this point you should have found the problem with your cable and/or your COM port, but there is still the possibility that the wideband unit can still not be seen from your PC. In this case it's probably that the RS232 inside the wideband unit has a problem. If you have a DIY unit then it should be easy to trace the problem using the supplied schematics. for a DIY unit you may have a bad RS232 transceiver (typically an ST202 or HIN202 DIP-16 package). A remote, but still possible, scenario is that the RS232 comms within the CPU has somehow died, and a CPU can fix the problem, but it's more probable you have a short or open circuit somewhere, or have not selected the correct port (or it's taken by another application).
  • I. If you can't find the problem, then emailing me with extra information may help me find your problem (and I will update this page), but I'm not a clairvoyant, and will be very unhappy if you ask me questions that are answered here, or are posed here for you to answer yourself!
  • J. Here's where you give up and send it for us to look at!