S45 ETL with Angle Sensor (Part 1)

Abstract Previous iHydrostatics post N6 shared intelligent pump control solution with angle sensor feature. If you missed this post, just simply reply N6 in Wechat iHydrostatics. We together shared the different designs of angle sensor from Rexroth, Danfoss, Eaton, Parker and Casappa. If you have any questions, comments or suggestions, feel free to leave it in iHydrostatics QQ Group: 426372753. iHydrostatics will always be with you.


iHydrostatics has promised to investigate more about angle sensor used in Danfoss S45 ETL control solution. In this post, iHydrostatics will be together with you to discover the secret of Danfoss S4 ETL. This topic will be divided into two parts: Part 1 will introduce the basic information about S45 ETL including the concept, features and outline; Part 2 will discuss the hydraulic circuit, control principle and difference between other similar solutions.

1What Is ETLOverviewETL is the abbreviation of Electronic Torque Limiting. Series 45 Electronic Torque Limiting control is designed to be fitted into existing pressure compensated/load sensing or mechanical torque control (MTC) systems. ETL unlocks total system performance potential by allowing infinite adjustment of torque limit settings through the electronic proportional control.

ETL cannot perform well without angle sensor. S45 angle sensor allows users to measure the angle of pump displacement. The angle sensor is an electronic sensor mounted to the housing of the pump, which reads the pump stroke angle based on the swash plate position. In this way, ETL can adjust the max. limiting pressure to avoid engine stall.

FeaturesThe Electronic Torque Limiting control consists of a normally closed proportional relief valve (PRV) integrated into a Pressure Compensated/Load Sensing control. This control operates as a PC/LS control, with the additional ability to limit load sense pressure using the integrated PRV by varying the current to the solenoid. When combined with an angle sensor, this control allows for a PC/LS control with electronic torque limiting.

Angle Sensor
o Measures real time swash plate angle (displacement) of the pump with high resolution
o Proven hardware with no interference parts
o Redundant (dual) integrated sensors
§ Improved measurement accuracy
§ Easy sensor fault detection
o PLUS+1 compliance block
§ Easy calibration of sensor and diagnostics
o Also available with other common control configurations (PC, PC/LS, RP, ON/OFF)
o IP67 and IP69K Rating with a 4 pin Deutsch connector
o Same package size as current electrical controls

Pressure Compensator/ Load Sensing pump with Electronic Torque Limiting control (PC/LS with ETL)
o Available in 12/24 volt configurations
o Normally closed control (NC), removal of signal to control or angle sensor defaults system to regular PC/LS functionality, allows for maximum uptime
o Similar hardware configuration as current electric controls
o Can be easily implemented into PC/LS systems

OutlineETL is a quite compact design, the whole outline dimension is no bigger than original configuration. So no more consideration needed for the installation issue.

2More about ETLETL’s secret is not just that little above , we are just starting our first step. If you are interesting in this topic, keep the pace with iHydrostatics to stride forward to the next episode. In N8 post, more details of ETL hydraulic circuit, control principle and difference comparison will be disclosed.
Keep up with iHydrostatics, the adventure of Danfoss S45 ETL won’t be exciting without your company.