UM344-2

INSTALLATION

resistance change of RTD per 1°C

Total length (L) =

resistivity of #24 AWG per foot

 

0.39 ohms

L =

 

= 14.8 feet or 7.4 feet for each lead.

 

 

0.0262 ohms per foot

A 0.3° offset error is caused by an extension lead wire (#24) length of 2.23 feet.

As the calculations indicate, extension lead wire added to a 2-wire RTD can cause serious offset error. A 2-wire RTD should not be used without determining that the results are acceptable.

The effects of lead wire resistance are compensated for by the Transmitter when 3 and 4-wire RTDs are used.

4.3.11 Shielding and Grounding

The preferred method of grounding the loop cable shield is illustrated in Figures 4-1, 4-2, and 4-3.

The following guidelines represent proven grounding practices that will reduce magnetically coupled interference:

ŸGround the cable shield at ONE point, as shown.

ŸPreferably, ground the cable shield at the Network power supply.

ŸWhen the cable shield is grounded at the power supply:

a)The cable shield should remain open (not connected) at the Field Instrument (Transmitter).

b)The shields of both cables at a Network Junction should be spliced. Alternatively, connect both to a terminal in the Box or Panel, provided that the terminal is isolated from ground.

ŸPoint-To-Point Network

Other permissible single point grounding schemes are:

a)The cable shield may be grounded at the Ground Connection in the signal terminal compartment of the transmitter's electronic housing. It is recommended that a separate ground wire be run from this Ground Connection to building ground to ensure a dependable ground.

The power supply (+) and (-) connections must be floated and the shields at Network Junctions must be connected as discussed above.

September 1995

4-15

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Siemens UM344-2 user manual Shielding and Grounding
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UM344-2 specifications

The Siemens UM344-2 is a cutting-edge industrial controller designed to meet the demands of modern automation and control systems. This powerful device is specifically developed for use in various applications, including manufacturing, process control, and machinery integration. The UM344-2 stands out for its versatility and robust performance in harsh industrial environments.

One of the main features of the Siemens UM344-2 is its high processing speed, which allows for real-time data processing and decision-making. The controller utilizes advanced microprocessor technology, ensuring quick response times and efficient operation. Its architecture supports multitasking, enabling it to manage multiple processes simultaneously without compromising performance.

The UM344-2 features a modular design, which provides flexibility in configuration and scalability. Users can easily add or remove modules to tailor the system to specific application requirements. This adaptability is beneficial for businesses that need to scale their operations or adjust to changing production demands. The controller is compatible with a variety of I/O modules, allowing for seamless integration with other equipment and systems.

In terms of connectivity, the Siemens UM344-2 supports various communication protocols, including Profibus, Profinet, and Ethernet. This versatility ensures smooth data exchange between the controller and other devices in the automation ecosystem, facilitating comprehensive monitoring and control. The inclusion of these communication standards enhances interoperability and allows for the integration of legacy systems with newer technology.

The Siemens UM344-2 is equipped with advanced diagnostic tools, which enable users to monitor system performance and detect potential issues in real-time. This feature reduces downtime and maintenance costs by allowing for proactive management of the system. The controller also supports remote access capabilities, enabling technicians to troubleshoot and configure systems from off-site locations.

Safety is a critical consideration in industrial environments, and the UM344-2 is designed with this in mind. It incorporates safety-certified features, ensuring compliance with international safety standards. Users can implement safety functions directly within the controller, streamlining system design and reducing the need for external safety components.

Overall, the Siemens UM344-2 exemplifies the fusion of technology and practical application, making it an essential component for businesses looking to enhance their automation processes. With its high performance, flexibility, and focus on safety, the UM344-2 is a reliable choice for industries aiming for efficiency and innovation in their operations.
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