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Sabertooth & SyRen Controllers

Using Dimension Engineering Sabertooth and SyRen Motor Controllers


UPDATE March 2015: Although some of the documentation below refers to the now retired 40SPU-1 card the connections between the Sabtertooth/Syren controllers and the new 64SPU-2 card are the same. 


UPDATE Jan 2014: V2.80 of the motion driver software (FS9/X version) adds a direct interface for  Dimension Engineering's Kangaroo motion control modules. See Section 18 of the on-line user guide for more detail.... This can now be used to build your motion platform drive using Syren or Sabertooth controllers of all sizes without use of the 64SPU-2 and related hardware.


Sabertooth controllers for motion platforms

Left to right - ST 2x25, SyRen 25 & ST 2x50

Using Sabertooth Controllers with the BFF motion drive - Quick Guide


Dimension Engineering supply a range of widely available compact DC motor controllers for robotics applications that look as if they may work well in a DIY motion platform servo drive.


I've had a plan for some time to try and add support for these controllers to the BFF Motion Driver software and servo drive hardware and have finally got around to doing it.


The DE controllers I've looked at here are the Sabertooth and SyRen models. The Sabertooths are two-channel units with continuous ratings of 25 and 50 amps (2x25 & 2x50), the SyRen 25 is a single channel controller, again with a current rating of 25 amps. Whereas the 25 amp models are limited to a 24V operating voltage the fan cooled 2x50 unit can handle higher voltages - up to 48V, which together with its 100amp peak rating makes for a fairly high power controller that might be useful in drives for heavier motion platforms. More recently the Sabertooth 2x60 has been introduced which covers up to 60 Amps per channel.



Sabertooth 2x50

The controllers all use the same set of Packetised serial commands and can be combined on the same TTL serial line to provide multi-channel drives. For smaller 3 DOF platforms 3 x SyRen 25's could be combined, or 1 x Sabertooth 2x25 and 1 x SyRen 25 to give control for 3 x 24V DC drive motors. In heavier platforms 2 x Sabertooth 2x50's could be used (with one channel spare in a 3 DOF drive, perhaps to add a yaw DOF later!).


My initial approach to configuring a system using these controllers was to attempt to drive them directly from the 64SPU-2 signal processor card - just as the Devantech MD03's are currently driven. Although this proved technically possible I wasn't quite happy enough with the controllability during start-up or shut-down operations, or with the data refresh rates I was getting with the set up (mainly limited by my microcontroller). In the end I decided that the most secure and fastest way of instructing the controllers was directly from the PC - the BFF PID Servo Controller software sends its motor speed and direction demands directly to the Sabertooth/SyRens through a USB to RS232 TTL level converter cable. The system wiring I experimented with is shown below.


BFF Motion Platform Drive with Sabertooth 2x25


NOTE the above wiring diagrams show the older 40SPU-1 signal processor card. The controller-side wiring to the new 64SPU-2 card is very similar - see the 64SPU-2 data sheet for details of the Syren high/low drive enable connection.


Each controller is configured for Mode 4 - Packetised Serial input and each is given a different address on the serial line. The serial input required is TTL level true (non-inverted) RS232 and this is probably most conveniently provided using a USB/TTL converter cable such as this. The 64SPU-2 signal processor card is still required in the system to provide the position feedback and to provide a safety stop signal for the SyRens if they are used - the Sabertooths have built-in serial timeouts and will automatically stop driving if the comms with the PC are lost, but the SyRen's don't.


BFF Motion System with Sabertooth controllers

Wiring for Sabertooth only systems

All the DE controllers mentioned have an emergency stop provision by pulling their S2 connections to a logic low state - this can be done by wiring to the 64SPU-2 and also combined with over travel limit switches to provide the necessary safety cut-off in the drive system. If you are only using Sabertooth controllers (no SyRens) then the controllers' S2 connectors do not need to be connected to the 64SPU-2 and can be wired directly through normally open actuator over-travel limit switches to ground - see the system wiring diagram for Sabertooth only controllers - left.





I have had all three models running unloaded motors with the PID Servo Controller software and the 64SPU-2 and the servo system appears to run smoothly and under control. I have also now run my mini motion platform (3) with the Sabertooth controllers for a short period of time without any obvious problems. The controllers were able to drive the platform under load with correct motion response and without signs of distress. I can get servo loop refresh rates of about 50 Hz which is fine for the majority of motions seen in the DIY motion platform. When running with FSX flight simulator best results are achieved with the motion software running on a LAN PC, although users with powerful multi-core machines may get satisfactory performance with FSX and the motion drive on the same PC.


Preliminary scoping of the logic connection lines on the controllers suggests there is not a great deal of electrical noise coming though to the logic connections from the high current/voltage motor side.


The approach looks promising and it may suit some builders better to use the Dimension Engineering controllers rather than the Devantech MD03's if local prices and availability are in their favour. Certainly the much higher power capacity of the Sabertooth 2x50 has given me some ideas about heavier platform drives.


The v2.6+ of the PID Servo Controller available on the site now supports the Dimension Engineering motor controllers.




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