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Motion Control Specialists
with special interest in R/C model helicopter control
PO Box 101, Glossop SK13 5ZW, England.
email: tech@csm-ltd.co.uk       Tel: +44 (0)1457 854680
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CSM Micro Gyros, Revision 4

Compatibility .... Features .... Revision 4 .... PC interface (SL560)......Technical Support.


Download SL560 manual                    Download SL560 PC interface manual                          

Download Rev 4 software       Download Rev3 software (available for LPT port only)

Download  SL420 manual (same for both versions)         Download SL310 manual

The SL range of gyros is now on Revision 4 internal software. If you wish to have your gyro upgraded, please send your gyro to PO Box 101, Glossop, SK13 5ZW. Your gyro will be checked over and the software upgraded - put your phone number in the package so we can let you know the state of your gyro, and take credit card details. Cost of checkover/upgrade and return insured postage is 12. If you are outside the UK, or need further details, please contact us at tech@csm-ltd.co.uk or phone +44 (0) 1457 854680

Please note that the new default settings are more appropriate for 30 size helicopters and up. Flyers of small electric models may not find a great advantage with Revision 4 software, and if you have a SL420 we would not recommend that you upgrade. If you have Revision 4 software and wish to fly a small electric model, with the SL560 you can use the PC interface to put the Heading Lock gain down to  26 and the acceleration gain up to 180. With the SL420, you will need the 'e' version - your normal version can be changed to 'e' for 7 - see details above about upgrading. We do not recommend the SL310 for small electrics.

Download test report from Russ Deakin - his initial findings when the SL560 (standard size) was first introduced. We're now on micro gyros, and revision 4, with a MuRata  sensor which is much better than the specifications of the sensor in the report.


Model: These gyros are recommended for all helicopters, particularly nitro and petrol (gasser) models. The default settings are not so suitable for small electric helicopters such as the T-Rex 450. For these we recommend either customizing the SL560, or using the SL420e (see above).
Belt driven models can suffer from static interference, so please use an anti-static spray on the belt to protect your radio gear from interference.
The SL560's customisability also makes it suitable for many specialist applications - please contact CSM for advice.

RC System: The wiring is compatible with all current 35MHz and 2.4GHz transmitters.
The gyro requires an auxiliary channel with travel adjustments to control the gyro mode/gain. It cannot be used with basic RC systems that lack such a channel. We recommend that you use an RC system that also provides travel adjustment on the rudder channel. Most current production computer RC transmitters have these facilities.

Servo choice: These gyros make the most of either a digital/super or a standard servo, since you can select Super Servo support during Quick-Setup.. Warning: Use of the Super Servo facility with servos not designed to accept their high frame rate may result in damage to a standard servo and will cause malfunction in flight. The Quick-Setup routine runs the servo in standard mode so it is always possible to access this routine with a standard servo in order to turn off the Super Servo facility.
For optimum performance, we recommend a high speed Super Servo or Digital Servo (0.1 seconds/60 degrees or less), . The gyro will run with any digital servo using standard (1520ms) pulsewidths. These servos will be run at 250 frames per second. Please note - servos with 760ms pulse width (eg Futaba S9251,S9256, BLS251, Logitech 6100T, Hitec 5083MG), cannot be used (but can with our SL720 gyro).
With a standard servo, set to Super Servo OFF, these gyros will work with any servo but we recommend a speed of 0.12 sec/60 deg. or better for best performance. These servos will be run at 70 frames per second.

Batteries, power consumption and wiring: Due to their two stage power supply regulation, these gyros will accept a supply voltage range of 4.1v to 7.2v. Please note that your RC system may be more restrictive. Many servos cannot be used above 4.8v, and CSM provide voltage droppers to fit between gyro and servo if needed - please see Spares and Accessories
Although the power consumption of the gyro unit itself is very modest, high performance gyros work the tail rotor servos harder and the power consumption may be high. We recommend that you use a good quality battery state monitor and check it carefully before each flight. You may wish to consider maintaining the charge in your receiver battery between flights by the use of a quality Delta Peak type field charger.

Computer: To use the PC interface of the SL560 you will need a CSM adaptor. These are available for the LPT (printer/parallel) port or USB. Unfortunately, the PC software cannot be run on a Mac. Please note: most people with IC helicopters find that they get very good performance with the default settings.

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If you have not previously used a CSM SmartLock gyro, you may not be familiar with the following features:

Quick Setup: Quick Setup is a simple routine which gets the gyro up and ready to fly. You enter it by toggling the gain switch back and forth whilst the model is on the ground.  The gyro will automatically pick up your stick centre and information about your radio gear, and you then set the gyro sense, servo type and servo travel limits using your transmitter sticks.

Optional digital servo support: In Quick Setup, the gyro can be set to work with either digital/super or conventional servos.

Quick Trim: Quick Trim is a simple method of correcting for any small linkage errors. Toggle the gain switch five times whilst in flight, and the gyro will correct the trim. Please do not use stick trim when flying these gyros as it may cause the stick centre information to become inaccurate.

Dual Mode switching: Two modes are available. The default setting has one as Standard and the other as Heading Lock, but with the SL560 you may alter these using the PC interface. The gyro gain channel is used to control these modes - the gain switch switches between the two modes, and the travel adjust (ATV) of the gain channel is used to adjust the gain in each mode.

Second Integral: SL310 only. Second Integral is the new Heading Lock. Instead of locking the helicopter to the desired rate of turn, it monitors the helicopter's response to actively correct heading errors. This gives stronger holding power with slower servos - although we still recommend a fast tail servo when possible,  for beginners, pairing the SL310 gyro with a slower (ie cheaper!) servo is a very economical option. Please note: this feature can cause the helicopter to behave strangely when being observed on the bench - do not be alarmed!

PC Interface: This feature is only available on CSM SL560 and SL720 gyros! See details and screenshot below for all the parameters that you can customise.

Also pioneered by CSM...
  • Built-in Exponential
  • Yaw Rate Demand to give consistent stick response regardless of gain - no need to change Rudder ATV
  • Command Conditioning to tidy up bouncy stick movements
  • Hi-Res pulse measurement and generation equivalent of PCM4096 (twice as accurate as the best transmitters currently available!)
PC Interface Parameters (SL560 only)

Acceleration Gain: Switch on the Acceleration Gain to make the most of a slower servo

Dual Independent Stop Tracking: Balances stops from left- and right-hand turns

screenshot, Sl560 software

Please note: the software now also accepts USB adaptors.

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Additional information on Revision 4
The internal software of the SmartLock gyros has been upgraded to take account of recent trends in model helicopter design and equipment. Please note: these changes are most relevant to IC models, so flyers of small electric models may prefer to stick with Revision 3. With the PC interface of the SL560 you can alter the parameters to suit small electrics - put the heading hold gain down to 26 and the acceleration gain up to 180. With the SL420 we recommend using the SL420e version (revision 4e software). The Sl310 is not recommended for small electrics.

How governors affect the gyro
With the use of an engine governor, such as CSM's RevLock, the gyro has the luxury of operating with much more consistent tail power. Even quite small rpm changes give rise to significant changes in tail power, meaning that the gyro gain has to be turned down to prevent the tail wagging when the helicopter rotor over-speeds. This is often the situation which limits the gain. Removing overspeed situations by using a governor allows significantly higher gains to be run.

However, a governor also increases the demands on the gyro. A governor maintains constant head speed by changing the torque output of the engine. So a governor generally introduces bigger variations in main rotor torque than are seen in un-governed systems and it is, of course, the responsibility of the gyro/tail rotor system to compensate for these torque variations.

In Revision 4, CSM’s gyro software has been extensively re-written to meet the new challenge. Those familiar with our Revision 3 gyros will notice a significant increase in lock and better suppression of tail swing in high torque situations.

In Revision 4 we have addressed the problem of increased vibration levels. In many gyro systems these cause low receiver battery duration and high wear rates on tail servo gearboxes. While our earlier gyros were class leaders in conserving power and tail servos, in Revision 4 we have increased the lock capability without dramatically increasing the demands on the servo.

Our new approach has, however, changed the way in which stop equalisation is achieved. Please see our technical support page on how to optimise the performance of your SL560 revision 4 gyro.

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All our helicopter products are distributed worldwide through RC Models Distribution Ltd, and should be available from your local model shop or mail order company. To find your nearest stockist see the RC Models shops page

phone +44 (0)1457 860001 or email sales@rcmodels.org
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