Radio Magnet Contact STM 250 User Manual V1.
Revision History The following major modifications and improvements have been made to the previous version of this document (V0.9): Version Major Changes V1.0 V1.2 • • • • • • • V1.3 • V1.1 • • • • • V1.4 • Chapter 2.5: The bits LRN and STATE in DATABYTE_3 have been inverted Chapter 3.2: Recommendations for suited magnets and positioning added Chapter 1.5 “Physical Dimensions of Magnet Housing” added Chapter 2.6 “Learning” fully revised and renamed Chapter 2.3 “Radio Telegram” revised Chapter 3.
Table of Contents T1. GENERAL DESCRIPTION ______________________________________________________________ 4 1.1 Basic Functionality __________________________________________________________________ 4 1.2 Typical Applications _________________________________________________________________ 5 1.3 Features Overview __________________________________________________________________ 5 1.4 Dimensions of Reed Contact Unit __________________________________________________ 6 1.
1. GENERAL DESCRIPTION STM 250 is a wireless magnet contact. The radio sensor is powered by a small solar cell and by that it works absolutely maintenance-free. An integrated energy store allows operation for several days even in total darkness. The reed contact housing and the magnet housing are very small. This means that the EnOcean magnet contact is unobtrusively mountable at every window frame made of aluminum, plastic or wood. 1.
1.2 Typical Applications • STM 250 is designed and qualified for the use in building automation & installation, not for industrial applications (in cause of ESD protection) • Typical applications are window, flap and door monitoring The STM 250 serves the 868 MHz air interface protocol of EnOcean. Together with the serial interface output of receiver device RCM 120, this product can be easily integrated into different application-specific system solutions.
Teach-in pushbutton: .............................................on-PCB (operating at open case only) Indicator for teach-in telegram transmission: .................... on-PCB Light Emitting Diode (beside teach in pushbutton) A change of the REED CONTACT status or pushing the teach-in button will wake the transmitter unit to send a radio telegram immediately (reed contact position, teach-in pushbutton status, unique 32-bit sensor ID, checksum).
Figure 4: Side view Figure 5: Front view Figure 6: Bottom view ©EnOcean GmbH, A. Anders Page 7 of 24 STM 250 User Manual V1.
1.5 Dimensions of Magnet Unit Dimensions of Magnet Unit: .................................. base 37 mm x 10 mm x height 5 mm Weight of Magnet Unit: .......................................................................................... 2g Material of housing: ........................................................................................ PC/ABS Color of housing: ........................................................
Figure 10: Front view Figure 11: Bottom view 1.6 Environmental Conditions Operating temperature: ..................................................................... -25 up to +65 °C Storage temperature: ..............................-25 up to +65 °C, -40 up to +85 °C for 1h max. Humidity:............................................................................................................ IP 44 1.7 Ordering Information Type EnOcean Ordering Code STM 250 S3001-C250 ©EnOcean GmbH, A.
2. FUNCTIONAL DESCRIPTION 2.1 Block Diagram Figure 12: STM 250 block diagram 2.1.1 Device power supply: Solar cell and Goldcap energy store The extremely powerful solar cell has been designed especially for the STM 250 for maximum unit performance at smallest dimensions. The active solar area is divided into two to provide independent device power supplies: a) Small active area: Main power supply b) Big active area: Gold Cap charging supply 2.1.
2.1.3 Wake-up timer / Reed contact / LRN pushbutton The wake-up timer supervises status changes of the reed contact and learn pushbutton. In addition, it provides wake-up time intervals for activating the processor. • Extremely low power consumption during sleeping time period (approx. 25nA). • The sleep mode is terminated immediately 1. by changing the status of the differential reed contact or 2. when pushing the learn pushbutton. • Cyclic processor wake-up time strongly depends e.g.
2.2 Solar Energy Balance Calculation In the following diagrams, you will find the energy store operation characteristics under the condition that the number of reed contact operations can be neglected compared to cyclic sending times of the presence signal (normal operation in practice). Negligible implies that reed contact operations are less than 10 times a day. Notes: • Configuration of the Goldcap energy store: To obtain the Goldcap nominal capacity some charging/discharging cycles are needed.
2.2.2 Reload time for one-night operation Illumination time for reloading energy store from working limit to 14 h operation in total darkness (typ. values) reload time [minutes] 40 30 20 10 0 100 1000 illumination [lux] Figure 14 2.2.3 Initial load time for filling energy store to capacity Load time STM 250 versus illumination of Goldcap from working limit to 90% of max. loading voltage (typ.
2.2.4 Maximum operation time in total darkness STM 250 operation time in total darkness (typ. values, initial loading of Goldcap is 90% of max. loading voltage) 10 operation time [days] 8 6 4 2 0 100 1000 illuminance on average [Lux] Figure 16 ©EnOcean GmbH, A. Anders Page 14 of 24 STM 250 User Manual V1.
2.3 STM 250 Radio Telegram For the transmission of the telemetric signals, EnOcean has defined a new dynamic radio data telegram that is adapted to the individual application.
t Fix: 12..27ms (-25...65°C) Variable: 0..9.5 ms (16 slots) Fix: 12..27ms (-25...65°C) Figure 17: STM 250 radio timing 2.3.4 Reliable radio transmission within systems operating many sensors The very short telegrams of EnOcean transmitters enable the operating of a large number of senders within the same radio cell; the error rate caused by telegram collisions remains extremely low. Statistically viewed, the transmission reliability is still greater than 99.
2.5 Serial Data Communication via Receiver Device RCM 120 The RCM 120 Receiver Device of EnOcean enables standard asynchronous communication to a micro-controller or personal computer with a decompressed and simple data structure (9600 bps, 1 start bit, 8-bit data byte with LSB first, 1 stop bit). Figure 19: Receiver device RCM 120 When the RCM 120 receiver is set to Mode 0 “Serial Interface”, it transfers out data blocks of information from the received RF telegrams.
STATUS byte as follows: Bit 7 Reserved Bit 3 Bit 0 RP_COUNTER Bits 0..3: RP_COUNTER RP_COUNTER = 0: original telegram RP_COUNTER > 0: repeated telegram Bits 4..7: reserved 2.6 Learn Pushbutton – Learning of STM 250 to a Receiver If necessary, the sensor radio transmitter STM 250 can be easily made known to the receiver RCM 120 – that has been set into learn mode – by simply triggering a STM 250 radio signal, for example by operating the LRN pushbutton.
3. APPLICATIONS INFORMATION 3.1 Unit Mounting Both the EnOcean Reed Contact as well as the EnOcean Magnet are very thin and flat. This means that the unit is unobtrusively mountable at every window or doorframe made of aluminum, plastic or wood. Mounting position of the Reed Contact is horizontal, vertically or even tilted. The arrow signs on the base of the Reed Contact should be directed downwards. In this mounting position, the STM 250 housing offers protection against splashing water drops (IP44).
Reed contact marking Figure 21: Planar positioning of the Magnet (Typical for door mounting) The round-pole magnet can be removed from the magnet housing. This enables smart embedding into wooden window casements in square position to the Reed Contact housing.
3.3 Transmission Range The main factors that influence the system transmission range are type and location of the antennas of the receiver and the transmitter, type of terrain and degree of obstruction of the link path, sources of interference affecting the receiver, and “dead” spots caused by signal reflections from nearby conductive objects.
3.5 FCC/IC Approval Requirements This device complies with Part 15 of the FCC Rules and with RSS-210 of Industry Canada. If this device is operated in compliance with the following requirements it can be operated without notification and free of charge in the area of the United States of America and in Canada.
4. TOOLS 4.1 Evaluation Kit EVA 100 EVA 100 is an evaluation kit to support a simple setting-up operation of the receiver side when the EnOcean sensor transmitter device STM 250 is evaluated. EVA 100 supports a rapid evaluation of the RCM 120 serial receiver mode (e.g. via PC monitor) and supports the fast development of applications.
5. DECLARATION OF CONFORMITY Available with start of volume production ©EnOcean GmbH, A. Anders Page 24 of 24 STM 250 User Manual V1.
