MX4428 MXP Engineering /Technical Manual

Document: LT0273

MXP Technical Description

 

7.2.3.4+5V ISO & +5V Batt

A second L1 secondary winding is used to produce an 8V supply, This 8V supply is poorly regulated and may vary from 7.5V to 10V depending on the 40V ISO load. The 8V supply is regulated by U11 to 5.2V.

This supply is then passed through D32 to produce the 5V supply for the CPU and logic circuitry. The 5.2V supply also passes through D31, to produce +5V Batt, and this supply contains a supercap (C68) which is used to keep this supply up after the power supply has shutdown. R66 is used to limit the charge current to the supercap. This supply is used to power the RAM on the MXP, and retain its contents during short (up to a few hours) power downs.

7.2.4MX4428 LOOP INTERFACE

7.2.4.1Loop Disconnect Circuitry

The MXP, like all MX4428 compatible Responders, includes a DISCONNECT relay (RL3) which is used to isolate shorts on the power supply loop.

Normally 24V power passes from one Responder to the next via the 24VIN terminal / DISCONNECT relay / 24 VOUT terminal path, supplying power to the Responder on the way through. D35, D37, R90 form a diode gate such that a loop short on either 24VIN or 24VOUT applies a low voltage to comparator U7:D. This generates a DISCON IN- signal to the microprocessor which then opens the DISCONNECT relay to isolate the fault. Depending on the time taken for the shorted section to be isolated, the power output of the MX4428 panel may collapse completely, removing power from all responders. Therefore it is necessary for them to respond rapidly to the DISCON IN signal and open the DISCONNECT relay in their last dying gasps before their power supplies collapse to zero.

Generally, all Responders on the loop respond in like fashion and break the loop supply. (Depending on the position of the short, and loop resistances, some may not open their DISCONNECT relays.) Starting from the Responder nearest the MX4428 Master, each Responder then makes a decision, based on the value of “MIN V” (refer to Figure 7.1) whether to re-connect the relay or not. If MIN V is less than +V/2, the loop fault is on one of its 24V terminals, so it will not re-close its DISCONNECT relay. If, however, MIN V is greater than +V/2 the fault lies beyond the next Responder and it can therefore apply power to that Responder.

The newly powered up Responder then makes a similar decision, followed by each successive Responder up to the Responder with the loop fault on its far side which will not close its DISCONNECT relay.

Similarly Responders on the other end of the Responder loop will close their DISCONNECT relays, up to the Responder connecting to the section of the loop with the short circuit.

With a single short circuit, all responders will eventually be powered up (receiving power from one end of the loop or the other), however the two responders on either side of the short will have their DISCONNECT relays open.

7.2.4.2Disconnect Relay Driver

U8A and U8B with Q10 and Q11 form a bridge circuit to drive DISCONNECT relay RL3. This is a magnetically latched relay to save power consumption. Its position can be switched by providing a short pulse of voltage, with the polarity of the voltage controlling the position.

Page 7-6

24 March 2006

Issue 1.5

Page 89 Page 91
Page 90
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Tyco 4 MX4428 Loop Interface, 3.4 +5V ISO & +5V Batt, Loop Disconnect Circuitry, Disconnect Relay Driver
Page 89 Page 91

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.
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