You will find a collection of common SRM troubleshooting advice here.

Further information can be found by consulting the SRM Manual [PDF - 7.0MB]

Please ensure you have read the 5 Essentials of use [PDF - 20KB] document and read this section. If you are still experiencing problems after reviewing this section please contact us.

When I connect my PowerControl to my computer when I'm running SRMWIN, I get the "blue screen of death" (my computer crashes and shows me a blue screen). What can I do?

This is a problem that happens sometimes with PCIVs and PCVs, on computers running newer versions of Windows XP and Vista. The problem appears to be related to multiprocessor support in the Windows OS. It is possible to disable the multiprocessor support, which resolves the problem.

To disable the multiprocessor support (this may have to be done each time you run SRMWIN), open the SRMWIN software.

• Press "Crtl" "Alt" and "Delete" simultaneously to bring up the Task Manager.
• Click on the "Applications" tab in the Task Manager to display the list of all programs that are running, and then go to Schoberer RadMestechnik Evaluation Program.
• Right mouse click, and select "Go to process" at the bottom of the list.
• Then right mouse click on "SRMwin.exe".
• Click *Set Affinity*, and then click one of the processors only. (The set affinity option will only be available if you have multi processor support....)

I have a new sensor cable but the SRM Powercontrol displays no power or cadence?

Incorrect sensor position is the most common cause of problems - new or old style cable sets it the same concept.

The receiving coil in the sensor cable needs to be aligned with the receiving coil of the PowerMeter!

The newer styled "L Bottom Bracket sensor does NOT suit ALL mounting situations. They are best suited for frames that have a large Bottom Bracket Housings, used with the latest SRM PowerMeter's, especially the compact series systems. In the case below the sensor needs to be raised approximately 10 mm to bridge the gap between the two coils. The coil of the PowerMeter is identified due to its orange color circling the diameter of the inside cover of the Powermeter, usually 5mm or so from the outside edge.

Note: Your SRM system will NOT work correctly if your sensor cable is mounted like the picture above.

The power reading is too high/low. What is the problem?

Both the slope and the zero offset must be set correctly.

To set the slope, connect the PCV to the computer and choose the Powercontrol set-up option. Now enter the slope (noted on the back of the crank) into the box labeled Slope and confirm by clicking OK. More Information: Set Cal Slope Powermeter.pdf [PDF - 1.3MB]

To set the zero offset, mount the PCV on the bike and connect it with the sensor cable. Rotate the crank backwards to start it, this will trigger a signal. Click on the Powercontrol keys Mode+Set. Wait for a few seconds until the highest value remains more or less constant. Now press the Set key to have the value accepted and exit the menu by clicking the Mode key.
More Information: Zero Offset Calibration.pdf [PDF - 1.1MB]

Should the power reading still be wrong, the crank must be calibrated again.

Zero offset frequency shifting more than +/- 10 Hz:

Possible causes:

• The sensor position in relation to he PowerMeter's transmit coil may be less then optimum.More Information: Sensor Mounting [PDF - 1.3MB].
• The PowerMeter has been moved from one temperature to another (i.e.. indoors to outdoors in the winter). This causes the metal to contract, and will change the zero offset frequency. For a crank with a fairly typical slope of 20.00 Hz/Nm, it is normal for the zero offset frequency to change about 7-8 Hz per degree Celsius. Solution: Allow the bike to acclimatise by leaving it outside for at least half an hour before riding. Check and set the zero offset frequency before the ride, and then recheck it after approximately 10 minutes to ensure that it has stabilised.
• The chain ring bolts may be loose. This allows the chain rings to move slightly on the PowerMeter, and will distribute force through it differently. Solution: Check that the chain ring bolts are tight (use 6 to 10 Nm of force to tighten them). Tighten every second bolt in turn, as this creates more constant pressure on the O-ring seal inside the PowerMeter.
• The crank bolts may be loose. It is very important that a thread lock product (i.e. blue Loctite) is used on these bolts, and that it is allowed to set before the cranks are used. Otherwise the bolts may loosen, which causes the zero offset frequency to become unstable. Solution: Remove the crank bolts, apply thread lock to the threads, and then reinsert the bolts. Tighten them with 6 to 10 Nm of force, and allow them to set for the time recommended on the package.
• The washer in between the crank arm and the PowerMeter is inserted incorrectly, or has cracked. There are different sizes of washers for older cranks, and not all of them are interchangeable. If the wrong one is in place, the crank arm will not sit tightly on the PowerMeter, and the zero offset frequency will become unstable. It can also cause the crank bolts to snap. Solution: Make sure that the right washer is inserted, and that grease is applied to it's surfaces before it is put into place in the PowerMeter.

The PowerControl will not hold a charge:

Possible causes:

• The battery has reached the end of its service life, and needs to be replaced. Solution: Return the PowerControl to SRM for battery replacement.
• The PowerControl has been left plugged in to the charger for more than 14 hours (PCIV only). This causes the battery to become overcharged. Solution: Allow the box to run down to 15-20% battery, then recharge for 10 hours. The battery should return to normal after a few cycles of recharging in this way.
• The battery has been run down to 0% and has switched itself off. If the PowerControl does shut itself off, it will need to be plugged in for about 20 minutes before the data can be retrieved. The data should remain in the box for a few days, even with an empty battery. Solution: Recharge the battery for 10 to 12 hours, and then let the charge run down to 15-20%. This charge may only last for a few hours, but after that the battery should return too normal (approximately 30 hours).
• The wrong voltage charger is being used. The charger provided is intended for 220V electrical sockets. Solution: If the SRM system is going to be used in North America, a 110V charger is available from SRM and is recommended.
Note:With PCVI, It can be charged using the USB adapter or charging device. It should be charged regularly and over-charging is not possible if left on charge for extended periods of time.

There is nothing on the display screen:

Possible causes:

• The PowerControl battery is dead. Solution: Send the PowerControl back to us to have the battery replaced.
• The PowerMeter has not been turned on. Solution: Turn the cranks backwards two or three times to switch the PowerMeter on.
• Moisture has entered the box and short-circuited the electronics inside. Solution: Send the box back to us to be fixed or replaced. In future, to prevent this happening, grease the connector between the sensor cable and the PowerControl before riding in wet weather.

There is water in the display screen:

Possible causes:

• There is a crack in the display housing, allowing moisture to enter the PowerControl.
  Solution: Return the PowerControl to us for a replacement display housing.

While installing the USB adapter a message is received that the driver is not digitally signed. What does this mean?

This message means that the driver has not been tested by Microsoft itself for compatibility with Win XP . Your adaptor will most certainly work with Win XP. If you receive this message click "Continue Anyway”.

Strange values or symbols appear on the display screen:

Possible causes:

• The battery is about to die. Occasionally this causes strange readings on the display, such as suggested zero offset frequencies (under the 'Pro' heading in calibration mode) in the thousands, an entire line of the display intermittently going blank, reporting that the battery has a charge of more than 100%, or the PowerControl refusing to shut off. Solution: Send the PowerControl back to SRM for a replacement battery.
• If it is only the power readings that are erratic, check that the power sensor is in place properly, and that the connector between the sensor cable and the PowerControl has been greased if you are riding in wet weather. If water enters through this connection, it is common to see spikes in power and cadence intermittently, starting about 20 minutes into the ride. Solution: Always grease the connector between the sensor cable and the PowerControl if riding in wet weather. Be gentle when removing the PowerControl from the cable, and always make sure that you hold the plastic connector and not the cable itself when pulling it out of the back of the PowerControl. Also, check that the sensor has been installed correctly.

My computer cannot find the Powercontrol.

There are several possible reasons for this.

First of all, please check that the Powercontrol is connected to the computer correctly.

If you are using the USB download cable, please check that is installed correctly. To do this click on the Window-key+Pause. A window labeled System Properties will appear. Choose the Tab Hardware and then the Device Manager option. A list of all available interfaces will appear if you double click on Ports. Your USB adaptor should be listed here and should not have a yellow exclamation mark in front of it.

If you have installed Active Sync or any similar software to enable an exchange of data with your PDA, please check that this software is not blocking a serial interface.

Important: The COM-port that is assigned to the SRM USB cable needs to be less than COM10. The SRM software will not recognize any COM-port greater than this. We recommend force the COM-port to a value less then 5

More Information:USB Cable Troubleshooting Guide [PDF - 1.3MB]

My system shows no power reading. What is the problem?

If your crank is relatively old, it could be that the battery in the Powermeter is empty. The battery is designed for a life-span of up to 1,000 hours. Fluctuations in temperature or leaving the Powermeter unused for a long time could most certainly lead to the battery in the Powermeter having to be changed after a shorter period of expected use. Please send the Powermeter in for the battery to be changed.

Another reason for the malfunction may be that the sensor is not positioned correctly. The cable on the sensor casing must be turned away from the bottom bracket axle and the sensor should be mounted as close as possible on the bottom bracket axle. More Information: Sensor Mounting [PDF - 1.3MB].

Power readings are constantly too high or too low:

Possible causes:

• The zero offset frequency has not been set properly. If the zero offset frequency is too high it will reduce the apparent power output, and conversely if it is too low it will increase the apparent power output. Solution: Reset the zero offset frequency.
• The slope being used to calculate power is incorrect. It is vital that the slope for the PowerMeter being used in entered into the PowerControl, otherwise all of the power data will be incorrect. This can be corrected later, once the training file has been downloaded into the SRM software. Solution: Enter the slope into the PowerControl. To do this, the PowerControl must be connected by the download cable to a personal computer that has the SRM software installed. The PowerControl must be on (press the Mode key once). Open the SRM program, go to the PowerControl menu, and select Setup. Enter the correct slope in the box labeled 'Slope of PowerMeter'. Click 'OK' to save and exit. If you do not know the slope for that PowerMeter, make a note of the PowerMeter's serial number (engraved on the back) and contact us.

The PowerControl average data and the Software average data doesn't match?

The difference is due to the way the PowerControl and software compute the data. This difference may seem confusing but it helps provide valid information about your training file.

The data the PowerControl stores is a table structured like this:

With one second sampling, you will get data for every second the PowerMeter is sending data to the PowerControl. Optionally you can set the PowerControl to record data every second that it is receiving a heart rate signal only. Please remember that the PowerMeter is designed to turn itself off if it does not get a cadence signal for more than 20 seconds. If the PowerMeter turns off, the PowerControl will stop recording data, unless it is receiving a heart rate signal and the "heart rate signal only" recording option is on.

The PowerControl can calculate the average of the data in the table, but only the data with Power and Cadence values greater than zero. Essentially, the PowerControl only averages data for power and cadence while you are pedaling. The time displayed on the "AVG" Screen is the total time pedaling. The "MAX" Screen shows the maximum values in the table for Power, Cadence, Heart Rate and Speed, and calculates the mechanical work you performed while pedaling and displays this value in kilo joules (kJ). Note: The calculation performed is the total time pedaling multiplied by the average power.

The PowerControl will also calculate time spent in training zones that you configure using the software. The default zones are 100W increments from 0 to 500. This display counts the data that falls into each training zone and displays the total time spent in that zone and the percentage of total time pedaling. Average heart rate and cadence data are also displayed for the data in each training zone.

When you download the data to the PowerControl, the software receives this data as a table of values.

The software performs statistical analysis on the data and graphs the results.

In one line or multi line view, the average data is shown at the top or bottom left of the graph (if configured). The time shown is the incremental time from when the PowerControl first recorded data to the last recorded data of the file. The Power is the sum of the work (kilo joules) divided by the total incremental time. This is valid because the effect of doing work on your body is a function of the duration of time during which that work was done. (See footnote) In order to provide accurate data in SRM analysis, it must calculate all data including zeros to observe the correct power - heart rate relationship.

The data shown on the PowerControl while riding is also valid because it tells you what intensity you cycled at during your training session.

How do I mark portions of my training file?

You may mark intervals using the PowerControl or within the software.

To see average data during portions of your riding, it is useful to mark intervals within your data. You can also mark an interval while riding by pressing the SET button. After you press SET, the screen will clear and an "I" will appear next to the time. The timer will begin recording the interval. When you want to stop recording, press SET again.

While recording you may:

• See your average and maximum values. Press MODE once for average, press MODE again for maximums.
• Check your time spent in training zones. Press PRO once, then press MODE to scroll through your zones. (See setting training zones in the PowerControl).
• Check the current values. Press PRO twice to see the current values. There will be a "T" next to the current time. You may check the user screen, average screen, and maximum screen by pressing MODE.
• Check the last interval values. Press Pro until you see an "L" next to the time. You may see the average and maximum values by pressing MODE.
More Information:Set Markers in Training.pdf [PDF - 1.3MB]

After you download your file and are viewing it in one-line or multi-line graphic, click a point in the graphic where you want to begin your interval, and drag across the graphic to the point where you want to end the interval. A dialog box will open and allow you to edit the interval by time, relative time, distance, or work. You may name this interval as well.

When you pass your mouse over each point in the graph, the software displays the values of that record in the banner at the bottom of the SRM Software Window. The data is formatted like this (with examples):

The title of the file is displayed in this format (sample data) at the bottom-left of the graph:

Whenever you select an interval for viewing, the title changes to:

How do I set training zones in the PowerControl?

To set the training zones in the PowerControl:

• Connect your PowerControl to your computer with the serial cable, run the SRM Win Software, click on the "PowerControl" menu and choose "Setup".
• Click on Training zones and a table will appear. You may enter six zones that run consecutively. Zone 1 must start at zero and the upper limit will automatically become the lower limit of the next zone.
• Click OK to set the training zones, click OK again to complete setting up your PowerControl.

The Periodic Analysis graphic fails to properly add up total ride times in each zone in the summarised data?

The graphic shows only the times while you were pedaling (i.e. values of zero are omitted). The total time will match the time shown above the "(0)File" Tab in one-line or multi-line view, if training zones are consecutive and all possible power outputs are included.

It is also possible to set training zones that overlap - i.e. 0-100 watts at any rpm and 0-100 watts at 91-200 rpm. The time spent in each zone will be shown, so the time spent in second instance will be accounted for twice. The total time will not match the time shown above the "(0)File" Tab in one-line or multi-line view.

Why is the maximum power shown on the PowerControl different from the maximum I see on the downloaded file?

The data shown on the PowerControl screen is the raw data calculated per crank revolution (average torque during the last completed revolution times the average angular velocity of the last pedal revolution), then smoothed over the previous 3 seconds (default, configurable under Setup PowerControl->Special) and updated every 1 second (default, again configurable as above).

The data that you download are the raw data points from each sample. To see how the SRM samples data, go to question number 11. These values may differ depending on the sampling settings you choose to use, but don't worry, all your work is being measured if you choose a higher sampling interval; remember to check your PowerControl data before downloading if you are not sure what sampling interval you use.

Also be aware that the smoothing function of the SRM software may not graphically show you the maximum power that you attained during your training. Use the F2 and F3 keys to change the smoothing of the graphs, and view short intervals at 0% smoothing to see exact power data.

How do I know the SRM is receiving data accurately?

Remove the chain from the chain rings of the PowerMeter, press the MODE + SET buttons simultaneously

Start zero calibration mode of the PowerControl by rotating the crank slowly and look at the number displayed on the far right side of the PowerControl (under the SET heading PC IV). This number should not fluctuate more than ±5 counts through the entire revolution.

If this number is significantly smaller at one crank position than at the other points, then at this position the PowerMeter data will not be received correctly, which would result in incorrect power readings. If this is the case, move the sensor and repeat the check until the data is transmitted consistently throughout the crank revolution.

Does the SRM need regular slope calibration?

Generally not. Not to be confused with zero calibration which should be performed regularly.

However, if you are achieving unrealistic or inconsistent power outputs a calibration check is advised. The slope should remain consistent over a period of years, and may only change after a battery replacement or repair.

For your own piece of mind it is advisable to check the slope occasionally (1-2 years)

You can perform your own static checks as described in the online manual, or send it to us for an "on-bike dynamic calibration"

The following presentation titled Validation of SRM power cranks using dynamic calibration was presented in Nov 99. It shows that although individual cranks may have errors when compared to the factory calibration. Once calibrated all but 1 out of 19 systems re-calibrated to within the specified 2.5% after 1 full year of use.