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Tyco MX4428 technical manual

Models: MX4428

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MX4428 MXP Engineering /Technical Manual

Document: LT0273

MXP Technical Description

 

Figure 7.2 Analog Loop Typical DC Level and Data Waveform

7.2.5.1Over-Current Protection

The current drawn by the analog loop passes through current sense resistors R22 - R26. When the voltage across these resistors exceeds approximately 0.65 volts (corresponding to a current of just over 400mA), the collector of Q2 begins to conduct. Thermistor RV3 and resistor R119 compensate for the fact that the VBE threshold voltage of Q2 varies with temperature. Q2 conducting pulls the gate of Q12 to +40V and switches off Q12. The drain of Q12 then drops to around 5V or less depending on the load on the analog loop. Q13 is then turned on by the current through R5. Q13 then holds Q12 off even though the overload is now gone and Q2 is no longer conducting.

This “latched” over-current situation can only be reset by the CPU. The CPU senses the absence of 40V through the sense resistors R68 and R67 and the signal OVERLOAD– going to a logic low. The CPU (periodically) tries to reset the over-current latch by applying a short (approx 5 ms) pulse to “40V RESET”. This pulse turns on Q4 and Q1, which turns off Q13. Q12 will then turn back on and stay hard on as long as there is no over-current.

For the duration of this 5 ms pulse, the latching action of the circuit is disabled, and Q12 will act as a linear current limiter. During this time the dissipation in Q12 can be up to 40V * 400mA i.e. 16 watts. This will be an excessive dissipation for Q12 if it continues indefinitely, which is why the reset pulse is limited to 5 ms, and indeed why the latching action is required in the first place.

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24 March 2006

Issue 1.5

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Tyco MX4428 technical manual
Page 91 Page 93

MX4428 specifications

The Tyco MX4428 is a cutting-edge device known for its robust performance in the realm of wireless communication and sensor acquisition. Tailored for applications in various sectors, the MX4428 is particularly well-suited for industrial automation, environmental monitoring, and smart city initiatives. With its advanced features, the device has gained tremendous popularity among engineers and developers looking for reliability and efficiency in data transmission.

One of the standout features of the MX4428 is its exceptional range, which can extend up to several kilometers under optimal conditions. This long-range capability ensures that data can be transmitted over vast distances without degradation in quality, making it ideal for remote monitoring applications. Additionally, the device operates on multiple frequency bands, providing flexibility in deployment based on specific regional requirements and regulatory guidelines.

The MX4428 utilizes a highly efficient radio protocol that enhances data throughput while reducing power consumption. This asymmetric data transmission method allows for low-duty cycle operation, extending battery life and autonomy. The device's energy efficiency is particularly beneficial in applications where frequent battery replacement would be impractical, such as in environmental sensors and agricultural monitoring systems.

Furthermore, the MX4428 is equipped with comprehensive sensor integration capabilities. It can seamlessly interface with various sensors, making it a versatile choice for collecting a wide range of data types. From temperature and humidity sensors to motion detectors, the MX4428 can serve as a central hub for data gathering and transmission, providing real-time insights into environmental conditions.

Security is also a paramount consideration in the design of the MX4428. It incorporates robust encryption and authentication protocols to safeguard data integrity during transmission. This feature is crucial for applications involving sensitive information or those that require compliance with strict regulatory frameworks.

In summary, the Tyco MX4428 is a powerful and versatile device that boasts a combination of long-range communication, low power consumption, and comprehensive sensor integration capabilities. Its robust security features further enhance its appeal for critical applications across various industries. Whether for industrial, environmental, or smart city use cases, the MX4428 stands out as a reliable solution that meets the demands of modern wireless communication landscapes.