APPENDIX A3 : HART and PSION Operating Instructions

1.0.HART CONSIDERATIONS

Special Considerations for HART

If the HART communications facility built into the control unit will be used at the time of installation or during its future working life, then it is essential that a resistive load of at least 250 Ohms is connected in the supply cable. This may be provided by other devices in the loop (Chart recorder, meter, etc.) or more usually by installing a standard 270 Ohm 0.25W resistor in series with control unit. In this way the master device will be able to signal to the control unit without the power supply short-circuiting the data.

In addition, excessive cable capacitance will attenuate the HART signalling and so the capacitance must

anyway be limited if HART communications is to be used. The RC time constant for the network must not exceed 65µs, e.g. if the network resistance is, say, 650Ω then the maximum network capacitance is 0.1µF.

HART transmitters are often given a Cn number where n is the multiple of 5000pF which the device presents to the network. In the case of MSM400 the value of n is 1 since its capacitance is below 5000pF.

Total loop resistance and capacitance

Additional equipment such as indicators or recorders may be inserted in the loop subject to the resistance and capacitance limits discussed above.

Cable trays

It is recommended that HART signal cables are not run alongside power cables.

1.1Multi-drop installations (MSM400 in HART digital mode)

Up to 15 transmitters may be connected in parallel with each other, and each must be set to a different HART address between 1 and 15. When HART transmitters are connected in multi-drop mode, each control unit draws a fixed current of 4mA.

Compatibility with other HART instruments.

Any HART instrument, regardless of the manufacturer, may be connected in parallel with another to create a multi-drop network. They may be combined with separately powered, current sourcing or sinking devices but care must be taken to ensure that the HART signal current passes through the 250W minimum impedance to establish communications. For full details of HART instrument availability, refer to the HART Communication Foundation publications or individual manufacturers' literature.

Handheld Communicators

A handheld communicator (HHC) may be connected across the network (downstream of the minimum 250 Ohm loop resistance) to programme or interrogate a HART control unit. Some HHC’s support only a subset of a transmitter’s functions, and will thus only access the control units Universal and Common Practice commands. However, the MSM400 is fully supported by the MOBREY-CK1 HHC and by the UNIVERSAL 275 HHC (provided the 275 is loaded with the transmitter’s Device

Description – contact Mobrey Measurement or the HART Communications Foundation for details).

IP258

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Emerson IP258 manual Appendix A3 Hart and Psion Operating Instructions, Hart Considerations
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IP258 specifications

The Emerson IP258 is an advanced industrial monitoring device designed to enhance operational efficiency and ensure optimal performance in various industrial applications. It is particularly suited for monitoring, controlling, and managing processes across diverse industries such as oil and gas, pharmaceuticals, food and beverage, and water treatment.

One of the main features of the IP258 is its robust and flexible architecture, enabling seamless integration with a wide range of field devices, sensors, and control systems. This adaptability ensures that the device can be tailored to specific operational needs, thus streamlining processes and enhancing reliability. Its modular design allows for easy upgrades and expansions, making it a cost-effective solution for companies looking to future-proof their investments.

The IP258 boasts advanced communication technologies, including support for various industrial protocols such as Modbus, Ethernet/IP, and Profibus. This versatile communication capability facilitates real-time data sharing and interoperability between different systems, promoting a cohesive operational environment. The device is equipped with multiple input and output options, which further enhances its functionality and connectivity with existing infrastructure.

Another standout characteristic of the Emerson IP258 is its user-friendly interface, which simplifies operation and minimizes training requirements. The intuitive graphical interface allows operators to easily visualize system performance, access historical data, and quickly identify anomalies. This ease of use not only ensures efficiency during normal operations but also aids in rapid troubleshooting and issue resolution.

The device is designed with high reliability and durability in mind, featuring superior environmental resistance to withstand harsh industrial conditions. Its rugged housing and advanced components ensure long-term performance, reducing the likelihood of unexpected downtime and maintenance costs.

In addition, the IP258 incorporates built-in data logging and analytics capabilities, enabling users to gather insights into operational trends and performance metrics. This feature is essential for predictive maintenance and proactive decision-making, ultimately driving productivity and minimizing operational risks.

Security is another priority in the design of the Emerson IP258. The device includes a comprehensive suite of cybersecurity measures to protect sensitive data and prevent unauthorized access, ensuring that operational integrity is maintained at all times.

Overall, the Emerson IP258 stands out as a powerful and versatile tool for industrial monitoring and control, combining advanced features, robust technology, and user-friendly design to meet the demands of modern industrial environments.
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