Understanding Snorkel’s Envelope Management System

Understanding Snorkel’s Envelope Management System

How far can you push the envelope? The envelope management system (EMS) on the Snorkel TB100J, TB120, TB125J and TB126J telescopic boom lifts helps to keep operators safely within the working envelope.

The EMS controls the boom position, elevation and extension for each boom angle and extension. Before operating, the system reads inputs from the machine’s built-in sensors, controllers and limit switches in order to detect potential issues with a sensor.

When the operator initiates a request to either lift, lower, extend or retract the boom, the EMS compares that request with the boom’s current position with respect to the working envelope. If the requested motion would not cause the platform to go beyond the working envelope, the EMS would then send a signal to the proportional valve to move the boom in the requested direction.

EMS indicator lights in green, white and red are located above the upper and lower control panels. Each color indicates whether or not the machine is ready to operate and/or within the working envelope.


When the machine is first started or after the EMS has been reset, the EMS will enter “Initializing Mode.” There will be a 7-10 second delay before boom functions become operational. During this time, the EMS reads inputs from the machine.

If all inputs fall within each of its set parameters, the machine will enter “System Normal” mode to indicate it is ready for operation. If any of the inputs fall outside of its set parameters, the machine will enter either “Alert Mode” (green light) or “Error Mode” (red light), depending on the input that may be out of range.

Green Light

Solid green light – Ready to operate

Flashing green light – Calibration needed

A flashing green light and 3 beeps after 5 minutes indicates “Alert Mode.” This indicates that the machine needs calibration. Contact Snorkel Product Support for assistance.

White Light

Flashing white light – Nearing working envelope

When the platform nears the working envelope, the white light will begin to flash, and the speed function will slow down. One or more functions may be restricted to keep the platform within the working envelope.

Solid white light – Edge of working envelope reached

If movement continues in the same direction and reaches the edge of the working envelope, the white light will turn solid, and the boom function will be stopped.

Red Light

The red EMS light/button indicates an “Error Mode,” typically resulting in restricted functions. It is also a reset button in case of a malfunction with the EMS system.

Flashing red light – Primary envelope exceeded

If the red light begins to flash and beeps in quick pluses, this indicates that the primary envelope been exceed.

Continuous flashing red light – Primary & backup envelopes exceeded

If the red light emits a continuous series of beeps and flashes, both the primary and backup envelopes have been exceeded.

Solid red light – Backup envelope exceeded

This indicates that the machine is experiencing a system or electrical failure, or that a farther extension beyond the backup envelope has been reached. Should the solid red light continue to illuminate after resetting the EMS system, contact Snorkel Product Support for assistance.

For operator’s manuals and the EMS Calibration and Troubleshooting Guide, visit The Platform.

This video and content posted in this section are provided for informational purposes only. To the fullest extent permitted by law, we will not be liable for any damages, including but not limited to, injury, loss, damage, cost or expense incurred in relation to or arising by reason of any person relying on the information from any video or posts in this section. While reasonable care is take in relation to these videos and posts, we do not guarantee or warrant the accuracy, reliability, completeness or currency of the information on these videos and posts. For further specifics and instructions, please refer to the operator manual of each respective piece of equipment.

The Toolbox™ Sign Up

Get expert advice on equipment service and safety, parts, care and maintenance, and more. Subscribe to The Toolbox™ for emailed updates.

Keep it simple with a single subscription to receive all Snorkel company news, events and product updates – direct to your inbox!

By submitting this form, you are consenting to receive marketing emails from: . You can revoke your consent to receive emails at any time by using the SafeUnsubscribe® link, found at the bottom of every email. Emails are serviced by Constant Contact