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RST240-E High Load, High Torque Motorized Rotary Stages with Motor Encoders User's Manual

RST240-E High Load, High Torque Motorized Rotary Stages with Motor Encoders


Zaber’s products are not intended for use in any critical medical, aviation, or military applications or situations where a product's use or failure could cause personal injury, death, or damage to property. Zaber disclaims any and all liability for injury or other damages resulting from the use of our products.


Zaber's autodetect peripheral axes are designed to be used effortlessly with Zaber's line of autodetect controllers. The RST240-E includes onboard memory that allows Zaber's controllers to autodetect the model and set reasonable parameters. See the Protocol Manual for more information on how to modify the settings. Damage to the axis may result if the settings are not correct. To use your Zaber peripheral with a third-party controller, review the motor, sensor, and encoder specifications and pin-outs carefully.

Noise Emissions

The A-weighted emission sound pressure level (SPL) of this device does not exceed 70 dB(A) during intended use.

Payload Caution

RST240B with Varying Payloads for Angular Momentum.png

This image shows a RST240-E with varying payloads to demonstrate the relative size of large payloads that meet the maximum angular momentum specification of 1.6kg-m²/s when rotated at the angular speeds listed below. The size of these solid cylindrical payloads was determined using the density of steel of 8,000 kg/m³. The maximum allowable rotational speed of the 300kg load is 12°/s or 2 RPM. The rated maximum speed of the device of 60°/s can be safely met with a 125kg payload, or less. It is important to determine the moment of inertia of your payload. In the event of a sudden stall from high speeds, higher inertia payloads will impart large forces through the drivetrain of the RST240-E, resulting in possible damage.

The below table lists the maximum allowable speed a particular payload can be rotated at, in order to not exceed the maximum angular momentum of 1.6 kg-m²/s for the RST240-E.

Payload, m [kg] Example Inertia, I [kg-m²] Maximum Allowable Speed, [°/s]
50 0.21 60
100 0.85 60
150 1.89 48
200 3.39 27
250 5.28 17
300 7.58 12

Conventions used throughout this document

  • Fixed width type indicates communication to and from a device. The symbol indicates a carriage return, which can be achieved by pressing enter when using a terminal program.
  • An ASCII command followed by (T:xx) indicates a legacy T-Series Binary Protocol command that achieves the same result. For example,
    move abs 10000 (T:20:10000) shows that a move abs ASCII command can also be achieved with Binary command number 20.
Not all ASCII commands have an equivalent Binary counterpart.

Device Overview


Your RST240-E peripheral is equipped with AutoDetect, a feature that allows a Zaber controller to automatically configure its settings for the peripheral when it is connected.

Tip lightbulb symbol.png Important: The controller should always be powered down before disconnecting or connecting your RST240-E peripheral.

To connect the peripheral to a controller:

  1. Power off the controller.
  2. Connect the RST240-E peripheral.
  3. Power on the controller.
  4. The controller will activate the peripheral shortly after it is powered on.


Recommended controller(s) for your RST240-E peripheral are provided in the product specifications. Zaber's controllers and peripherals are designed for ease of use when used together. Optimal settings for each peripheral are automatically detected by Zaber's controllers when the device is connected.

For reference, the pinout for the peripheral cable connectors is shown below:

Pinout for D-sub 15 Connectors (peripherals)

T3A Peripheral (male) T3-DB15-male-connector-annotated-300.jpg
T4A Peripheral (male) T4-DB15-male-connector-annotated-300.jpg
Pin # Function
1 +5V for Limits & Encoder
2 AutoDetect Data
3 reserved
4 Away Sensor
5 Home Sensor
6 Ground
7 Motor B1
8 Motor A1
9 AutoDetect Clock
10 Encoder A
11 Encoder B
12 Encoder Index
13 Ground
14 Motor B2
15 Motor A2

Not all pins are used for all models

Alternate Controllers

The RST240-E can be controlled by any 2-phase stepper motor controller with limit sensor and appropriate encoder input. We do not recommend using your own controller unless you are familiar with how to control a stepper motor with hall sensor limit switches. Damage to the stage due to incorrect wiring is not covered by warranty.

Motors & Encoders

For motor and encoder information see the RST240-E product page

Limit Sensors

Hall effect sensors are used in the RST240-E as home sensors. The Hall sensors used are part number A1120LLHLT-T made by Allegro. Click here for data sheet. Your controller should be configured so the stage stops immediately (quick deceleration) when the sensors are triggered.

  • PCB wire colour code:
    • 5 Vdc input - red
    • Home signal - yellow
    • Away signal - white
    • Ground - black

The Hall sensor has an open-collector output. The default output is high impedance when the Hall sensor is not active. When the sensor detects a magnet, the Hall sensor pulls the output low to ground.

Hall sensor wiring diagram.png

If you are not using a Zaber controller, ensure that your controller has a pull-up resistor on the output line of each Hall sensor as shown in the diagram. The bypass capacitor is optional, but may help to eliminate false triggering in noisy environments. The typical value for the pull-up resistor (RLOAD) is 10 kΩ and for the bypass capacitor is 0.1 uF to 1 uF. The larger the capacitance, the better the noise filtering but the slower the response time.



Secure the RST240-E with 4 M8 (or 5/16"-18) socket cap screws, 40 mm or longer, by the 5 M8 mounting holes on the bottom flanges of the stage. There are also M6 threaded holes on the side of the stage available for mounting purposes. See the RST240 web page for dimensions, technical specifications and other details.


RST240-E devices use precision worm gears for rotary motion. To insure long service life and the highest performance, it is necessary to keep the worm gear mesh lubricated.

The worm gear should be re-greased after the first 200 hours of operation and every 1000 hours of operation thereafter. Many factors affect the re-lubrication interval including temperature, contamination, and load. Inspect device for noise or vibration and re-lubricate based on inspection results. At high torque loads, the re-lubrication interval will be shortened, inspect the device more frequently depending on application.

Temporarily remove power to the device before attempting to lubricate. Remove any payloads from the device stage top if they pose tipping, crushing, pinching and/or other hazards.

Slowly rotate stage (<5 RPM) while adding 7.5 cc's of lubricant into the grease fitting. The stage should complete a full revolution before all 7.5 cc's of lubricant are added. It is recommended to rotate the stage 10 revolutions clockwise and counterclockwise to distribute the grease. Grease with DuPont Molykote® G-4700 or similar viscosity synthetic NLGI Grade 2 lithium thickened grease with solid lubricants. All devices come pre-lubricated and are ready to go out of the box.

If RST240-E devices are used in applications where only a small angular portion of the rotational travel range is used, occasionally rotate the stage throughout its full travel to maintain an even lubrication film over the entire worm gear and redistribute the lubrication in the bearings.

Warranty and Repair

For Zaber's policies on warranty and repair, please refer to the Ordering Policies.

Standard products

Standard products are any part numbers that do not contain the suffix ENG followed by a 4 digit number. Most, but not all, standard products are listed for sale on our website. All standard Zaber products are backed by a one-month satisfaction guarantee. If you are not satisfied with your purchase, we will refund your payment minus any shipping charges. Goods must be in brand new saleable condition with no marks. Zaber products are guaranteed for one year. During this period Zaber will repair any products with faults due to manufacturing defects, free of charge.

Custom products

Custom products are any part numbers containing the suffix ENG followed by a 4 digit number. Each of these products has been designed for a custom application for a particular customer. Custom products are guaranteed for one year, unless explicitly stated otherwise. During this period Zaber will repair any products with faults due to manufacturing defects, free of charge.

How to return products

Customers with devices in need of return or repair should contact Zaber to obtain an RMA form which must be filled out and sent back to us to receive an RMA number. The RMA form contains instructions for packing and returning the device. The specified RMA number must be included on the shipment to ensure timely processing.

Email Updates

If you would like to receive our periodic email newsletter including product updates and promotions, please sign up online at (news section). Newsletters typically include a promotional offer worth at least $100.

Contact Information

Contact Zaber Technologies Inc by any of the following methods:

Phone 1-604-569-3780 (direct)
1-888-276-8033 (toll free in North America)
Fax 1-604-648-8033
Mail #2 - 605 West Kent Ave. N., Vancouver, British Columbia, Canada, V6P 6T7
Email Please visit our website for up to date email contact information.

The original instructions for this product are available at

Appendix A: Default Settings

Please see the Zaber Support Page for default settings for this device.