Taking the ­temperature

Taking the ­temperature

Continuous temperature monitoring with ABB’s new CM-TCN relays helps ­protect critical assets from expensive failures. The CM-TCN sets a new ­benchmark in ease of use and efficient setup. An embedded communication interface means the relay can be enabled easily in ABB Ability™ Energy and Asset Manager.

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Brigitte Dien, Anatoly Kosyakin ABB STOTZ-KONTAKT GmbH Heidelberg, Germany, brigitte.dien@de.abb.com, anatoly.kosyakin@de.abb.com

Temperature measurements are of interest in almost every industry because they help users understand and predict asset health. To help extend the advantages of temperature monitoring to more equipment and installations, ABB has introduced the CM-TCN temperature monitoring relay →01. The CM-TCN is equipped with up to three sensor circuits that accommodate inputs from common temperature sensor types and provide a convenient way to measure temperature locally. Relay outputs can execute appropriate actions when a particular temperature threshold is crossed. The relay can be set up via a smartphone or the integrated LCD and can connect to the cloud and ABB Ability Energy and Asset Manager to provide complete remote visibility of asset and electrical system behavior.

01 The CM-TCN relay.
01 The CM-TCN relay.

LCD for easy reading and parametrization
Ease of readout and setup were main considerations in the CM-TCN design philosophy. A back-lit LCD mounted on the front of the relay displays the currently measured values and maintenance data. The unit’s symbol-based menu structure can be accessed by depressing and turning the push-rotate button below the display with a screwdriver →02. A symbol-based interface eliminates language localization issues, increases efficiency in after-sales support and makes it easy to set thresholds and parameters. Password-protected access and a parameter lock improve security.

Event history, an operating hours counter, device statistics and other data are accessible from the menu. The relay offers predefined factory profiles (settings) to shorten installation times for frequently used applications such as temperature monitoring of transformers, or bearings and windings of electric motors. Parameters can also be individually set and saved in one of four user profiles. Further, an inbuilt simulation function lets the customer check that the relay setup is correct before it goes live.

Parametrization via a smartphone app
ABB’s Electrification Products intuitive Configurator (EPiC) is a free smartphone app that allows configuration, installation and commissioning of, and assistance with, ABB’s low-voltage portfolio, such as the CM-TCN. The app communicates with the CM-TCN relay via near-field communication (NFC) →02. NFC is an international transmission standard based on radio-frequency identification (RFID) technology for contactless data exchange. NFC is already integrated into most electronic devices, such as tablets and smartphones, and is part of everyday life – eg, for contactless payment. By simply touching the smartphone onto the CM-TCN, EPiC can carry out parametrization and copy settings between multiple devices via NFC – even if the relay is not powered up. The ability to set up the relay when it is switched off allows relays to be configured off-site, thus significantly shortening installation time – by 80 percent in some cases. This is especially relevant for original equipment manufacturers (OEMs) and panel builders.

02 The CM-TCN relay can be configured from a smartphone. The LCD home page displays current readings. Any data available via the LCD is also available via the app.
02 The CM-TCN relay can be configured from a smartphone. The LCD home page displays current readings. Any data available via the LCD is also available via the app.

Relay status and measured values are displayed in the app and sets of parameters can be stored there and copied to other devices by simply tapping the smartphone on them. The user can also view historical data on the smartphone →02.

Thermal protection and condition monitoring
CM-TCN relays can measure temperatures in up to three sensor circuits, using the most common sensors (positive temperature coefficient (PTC) thermistors, Pt100, Pt1000 and NTC). The wide temperature measurement range of -200 to +850 °C covers almost all conceivable applications. The relay itself can withstand an ambient temperature range of -25 to 60 °C.

The relay’s threshold settings are very flexible. Pre-alarm and alarm thresholds may be set according to application needs. For example, the first relay circuit can be assigned as a pre-alarm, the second as an alarm and the third as a sensor error alert. Nine signals are available for assignment to allow various combinations of tripping thresholds.

CM-TCN relays offer seven preconfigured factory profiles for the following applications:
• Motor winding protection with Pt100 sensors (factory profile 1 and factory profile 3)
• Motor bearing supervision with Pt100s (factory profile 2)
• Motor winding protection with PTCs (factory profile 4)
• Transformer supervision with Pt100s (factory profile 5)
• Transformer supervision with PTC thermistors (factory profile 6) • Individual temperature supervision with PT100s

For example, factory profile 5 allows transformer supervision with three escalation steps. Threshold 1 is set to 130 °C and if the threshold is reached, relay 1 trips, which starts ventilation for cooling the transformer. Additionally, a cyclic switching function is assigned to relay 1 to switch the relay once a week for 15 min to keep the fan from clogging.

Threshold 2 is a pre-warning at 140 °C and a trip of relay 2. In addition to the threshold configuration, the sensor error signals are assigned to relay 2. A wire break or short-circuit in the measuring circuits will then cause relay 2 to trip. Threshold 3 is a critical temperature of 155 °C, at which value the transformer will power off by means of relay 3. Relays 1 and 3 operate as normally open contacts (ie, an open-circuit principle) and relay 2 as normally closed (closed-circuit). All relays automatically reset when temperatures drop below the threshold values, taking hysteresis into account.

The operating logic and the settings are displayed in →03.

03 Block diagram of factory profile 5 – transformer supervision with Pt100s.
03 Block diagram of factory profile 5 – transformer supervision with Pt100s.

If the factory profile settings do not fully meet the application requirements, they can be modified. For example, the temperature values of the thresholds can be changed, while keeping sensor type selection and relays assignments as defined by the factory profiles.

CM-TCN devices also allow free configuration:
• Sensor setting – definition of sensor type used for each measuring channel (Pt100, Pt1000, PTC, NTC, bi-metal or none).
• Signal configuration – definition of threshold values, on/off delays and hysteresis.
• Relay assignment – mapping of signals (thresholds), sensor error signals and a bus fault signal to the three relays available in CM-TCN devices.

By providing early detection of unacceptable temperature rises and alerting the operator to the need for maintenance, temperature monitoring ensures that applications remain operational and asset lifetime is improved. Thermal protection and condition monitoring can also be accomplished remotely via a Modbus link and ABB Ability Energy and Asset Manager. Remote management improves safety as personnel no longer need access to the switchboard to read measurements.

The relay can detect unacceptable temperature rises that shorten the lifetime of electrical motor bearings and windings. But due to its flexible configuration options it can also be used, for instance, for temperature monitoring of busbars and cables, allowing early detection of issues related to tightening, which result in the need for maintenance.

Built-in connectivity
The CM-TCN temperature monitoring relay uses the Modbus RTU communication protocol over RS-485 to support data transfer. An RS-485 communication interface is embedded in the relay and requires no additional installation →04. This communication interface makes it possible to remotely:
• Read temperature measurements, the relay state and temperature sensor status.
• Access condition monitoring data such as event history, operating hours counter, maintenance counter, or statistics.
• Configure the monitoring relay.
• Reset the history and settings (trip counter, event history, etc.)
• Read system information (serial number and firmware version).
• Control output relays remotely.
• Define bus fault reaction of output relays if a communication bus error occurs.

04 Multiple relays can be connected via RS-485.
04 Multiple relays can be connected via RS-485.

Cloud integration with ABB Ability
As stated above, the ABB Ability Energy and Asset Manager cloud solution gives remote visibility of electrical system behavior. This visibility provides insights that help operators minimize costs and risks and maximize performance and safety across all operations. Communications between an ABB Ability Edge Industrial Gateway, for example, and the relay is conducted via the relay’s embedded Modbus RS485 communication interface. The edge gateway itself uses a state-of-the-art cybersecurity protocol built on ABB and Microsoft expertise to exchange data with the ABB cloud platform.

05 Configuration example.
05 Configuration example.

→05 shows an example communication architecture that integrates a range of devices into the ABB Ability Energy and Asset Manager and local network. In this setup, the data received in the cloud from the CM-TCN is organized as a user-friendly widget for the remote temperature monitoring of a variety of assets. In such an architecture, temperature sensor readouts can be compared in order to identify trends, giving valuable insights about asset temperature behavior. Additionally, the user can set up SMS or email alerts to notify key personnel should a relay trip or sensor errors occur. A periodic report with temperature values can also be scheduled.

Rewriting the rules
By keeping an eye on temperatures – either from the cloud, in a control room, or locally – operators can help minimize cost and risk while maximizing performance and safety. Setup via the relay’s LCD or with a smartphone is simple and since configuration can be performed without powering up the device, installation times can be significantly shortened. Because this one relay covers such a wide range of applications, inventory costs are reduced.

The ABB CM-TCN relay rewrites the rules of temperature monitoring in industrial settings. 


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