7.1OUTPUTS

7.2CURRENT OUTPUT

The operation of the current output is set up by four different parameters and is always controlled by the process variable (PV), which is normally % suspended solids. These are found in SETUP – OUTPUT – CURRENT OUTPUT.

1.Lower range value (Low range val)

This is the value of PV which corresponds to the minimum current output, either 0 or 4mA

2.Upper range value (Up range val)

This is the value of PV which corresponds to the maximum current output, 20mA.

3.Alarm action

This is the value to which the current output is driven under alarm conditions and is selectable from a list.

3.6mA

21mA

Hold (i.e. hold last reading)

For alarm conditions see the section below titled ALARM.

4.0-20mA or 4-20mA setting (0/4-20mA)

This parameter sets the current output range to either 0-20mA or 4-20 and is selected from a list.

5.If required the 4-20mA can be trimmed using an external calibration meter. (For details see Section 7.8)

7.3RELAY OPERATION

The MSM400 controller offers various options for operating the relays.

There are 2 relays that are programmable to different modes, set point operation, de-sludge, alarm and fault. The mode of operation is selected through the SETUP – OUTPUT – RELAY – Relay Mode menu. The default mode for Relay 1 is set point operation and Relay 2 default mode is alarm.

a) SET POINT OPERATION

It is possible to program both relays for set point operation. These are found in SETUP – OUTPUT – RELAY. The process value (PV) controls the relays.

1.Relay on point (RL* On Point)

This is the value of PV at which each relay will turn on

2.Relay off point (RL* Off Point)

This is the value of PV at which each relay will turn off

3.Relay minimum on time (RL* Min ON)

This is the minimum time that the relay will stay on for and this takes priority over the maximum on time.

4.Relay maximum on time (RL* Max ON)

This is the maximum time that the relay will stay on for.

It is important to note that this function only operates when the minimum off time is set to a non zero value.

5.Relay minimum off time (RL* Min OFF)

Once the relay has turned off this is the minimum time before the relay will turn on again. (*=1or 2 i.e. relay one or two)

If both on and off parameters are set to zero then relay is turned off.

If the on and off points are equal (non-zero) the relay is on when PV is above the set point and off when below. If both minimum and maximum on times are set to zero (default) then they are not used.

(See also the example in “NAVIGATION IN THE MENU SYSTEM”).

b) DESLUDGE

When in desludge mode the relays operate as explained above.

IP258

27

Page 27
Image 27
Emerson IP258 manual Outputs Current Output, Relay Operation

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.