Why are all PT100 sensors in FCC on my TECSYSTEM NT935-4 Controller?
If all the PT100 sensors are in FCC, it might be due to an incorrect sensor connection or the terminal block being inserted upside down. Check the connections and the terminal board to resolve this issue.
What to do if the main switch of my TECSYSTEM NT935-4 Controller trips suddenly on just one channel?
If the main switch trips suddenly, and only one channel caused the trip while the temperature is at standard levels, check the temperatures recorded in T-MAX. Also, activate the FCD function.
What to do if one of the four channels is in FAULT due to FOC/FCC in TECSYSTEM Controller?
If one of the four channels shows a FAULT due to FOC/FCC, check the connections of the Pt100 sensors.
How to troubleshoot if TECSYSTEM NT935-4 doesn't switch on, but the supply to terminals 40-42 is correct?
If the control unit does not switch on, but the power supply to terminals 40-42 is correct, verify the following: Ensure the connector is correctly inserted into its housing, the wires are tightened, and there is no evidence of burning on the connectors. Disconnect the power supply, perform these checks, and then reconnect the power.
Safe handling and connection of the universal power supply unit, including precautions against damage.
Emphasizes that all operations must be performed by qualified technicians to prevent injury or damage.
Details conditions that void the warranty, such as opening the unit, and outlines repair procedures.
Explains the unit's display modes like SCAN, AUTO, MAN, and T.MAX, and how to cycle through them.
Describes how to access and navigate the programming mode using the PRG key.
Provides notes on the operation and system messages during SCAN and MAN modes.
Details procedures for testing unit LEDs and alarm relays using the TEST key.
Explains how to silence alarm signals using the RESET key and its automatic deactivation.
Explains how alarms and ventilation relays function and are controlled by temperature thresholds.
Details the behavior of the FAULT contact under failsafe conditions and its triggering events.
Lists fault messages, their reset conditions, and the sequence of error detection.
Provides important notes and considerations for programming the unit, including data saving.
Details settings related to temperature sensors, diagnostics, and potential issues.
Covers requirements and potential problems for connecting Pt100 sensor extension cables.
Lists the technical specifications for Pt100 extension cables, including construction and materials.
Explains the redundancy concept and how the Voting function compares sensor data for reliability.
Describes how to diagnose and handle internal memory or data corruption issues.
Explains how to use the HFn function for periodic fan operation checks and verification.
Key operational guidelines for setting up and using the Modbus network communication.
Details the recommended wiring and cabling for RS485 twisted pair connections.
Describes the format of data frames and packets transmitted over the Modbus network.
Explains Modbus function codes 3 (holding register reading) and 16 (multiple register writing).
Guidelines and considerations for remote configuration and data storage via Modbus.
Lists Modbus error codes generated by wrong requests or data, and their meanings.
Identifies programming errors and incorrect settings that result in ILLEGAL_DATA status.
Advises on optimal polling frequencies for Modbus communication to avoid system overload.
Defines the structure of Modbus header information, commands, and register mapping.
Maps Modbus registers for system settings, status, fan control, and temperature configuration.
Details Modbus registers for configuring fan ON/OFF thresholds and related settings.
Maps Modbus registers for temperature readings and setpoints for channels 1 through 4.
Maps Modbus registers for configuring individual channel settings and parameters.
Maps Modbus registers for retrieving historical status and data for each channel.
Explains the meaning of bits for various register categories including status and settings.
Details the specific bit meanings for CPU error reporting and configuration settings.
Explains how to configure Fail Safe modes for ALARM, TRIP, and FAULT relays.
Describes the 4-20mA output, its programming modes, and current-temperature ratios.
Explains the FCD function for detecting rapid temperature increases and its applications.
Outlines the terms and conditions of the product warranty, coverage, and limitations.
Provides solutions for common problems like unit not switching on, display errors, or sensor faults.
Instructions for the proper disposal of electrical and electronic equipment according to directives.
The NT935-4 is a temperature protection control unit designed for monitoring and managing temperatures in various applications, particularly transformers. It offers a comprehensive set of features for temperature measurement, alarm management, fan control, and communication, ensuring the safe and efficient operation of the monitored system.
The primary function of the NT935-4 is to monitor temperatures using Pt100 RTD sensors. It supports up to four sensor inputs, allowing for multi-point temperature surveillance. The device continuously displays temperatures and provides visual indications of alarm and fault conditions through dedicated LEDs.
A key aspect of the NT935-4 is its robust alarm management system. It features two alarm relays (ALARM and TRIP) that activate when predefined temperature thresholds are exceeded. These relays can be configured for either normally open (NO) or normally closed (NC) operation, offering flexibility in system integration. Additionally, a dedicated FAULT relay indicates sensor or operating failures, enhancing system reliability.
The unit also incorporates a cooling fan control function, allowing it to manage up to two fans (FAN1 and FAN2) based on temperature thresholds. This helps in maintaining optimal operating temperatures and preventing overheating. The fan control can be configured per channel, enabling tailored cooling strategies.
For advanced monitoring and control, the NT935-4 AD version includes Modbus RTU RS485 output and an optically isolated 4-20mA output. The Modbus interface allows for remote data acquisition and programming, integrating the unit into larger control systems. The 4-20mA output provides an analog signal proportional to the temperature, suitable for external display or recording devices.
The device features a "Fail Safe" function, which ensures that in the event of a power failure or internal fault, the relays revert to a safe state, preventing unintended operations. This function can be enabled or disabled based on specific application requirements.
An innovative "FCD Function" (Fast Change Detection) is also available, which analyzes the rate of temperature increase (°C/sec). This feature helps in identifying rapid temperature changes due to sensor faults, induced interferences, or specific operational issues like a blocked motor rotor, inhibiting false alarms and providing early warnings.
The "Voting Function" enhances reliability by comparing temperature values from multiple sensors. When activated, the TRIP contact will only switch if the TRIP threshold is exceeded on at least two channels over a specified period, reducing the likelihood of false trips caused by a single faulty sensor or localized anomaly.
The NT935-4 offers a user-friendly interface with a 3-digit display for temperature and channel information, complemented by LEDs for status indication (SCAN, AUTO, MAN, T.MAX, ALARM, TRIP, FAULT, FAN1, FAN2).
Users can select different display modes:
Programming the unit is straightforward, accessed via the PRG key. The programming menu allows users to set alarm and trip thresholds, configure fan control parameters, enable or disable channels, and adjust communication settings (for AD version). The system includes safeguards such as automatic exit from programming after inactivity and warnings for incorrect programming.
The device supports a "LED Test" function to verify the functionality of all display LEDs and an "Alarm Relay Test" to check relay operation without external devices. These tests contribute to easy maintenance and troubleshooting.
Alarm signals can be silenced using the RESET key, which causes the ALARM LED to flash until the temperature drops below the alarm threshold.
For the AD version, remote programming is possible via Modbus, allowing for configuration changes from a central control system. The Modbus mapping table provides detailed information on accessible registers for reading and writing data.
The NT935-4 is designed for durability and ease of maintenance. It features a self-diagnostic circuit that helps identify internal issues, such as EEPROM memory damage ("Ech Err") or measurement circuit faults ("CAL Err"). In such cases, the unit provides clear messages, guiding users to contact technical service if necessary.
Sensor diagnostics (Fcc, Foc, Fcd) are integrated to detect short-circuited, interrupted, or rapidly increasing temperature sensors, providing immediate warnings and activating the FAULT relay. This helps in quickly identifying and addressing sensor-related problems.
The unit's design includes protection against electromagnetic interference and a robust housing, contributing to its longevity in industrial environments. Removable terminal strips simplify wiring and replacement.
For optimal performance and to prevent reading anomalies, the manual provides detailed instructions on proper sensor installation and cabling, including recommendations for cable type, screening, and routing. Adherence to these guidelines is crucial for accurate temperature measurement and reliable operation.
The "Fan Test" function allows for periodic activation of cooling fans for a set duration, regardless of temperature, ensuring that the fans and their control apparatus are functioning correctly. This proactive maintenance feature helps prevent cooling system failures.
In case of persistent problems or complex issues, the manual directs users to contact TECSYSTEM's technical department, providing contact information for support. The device also comes with a warranty, subject to proper installation and use as outlined in the manual. Information on equipment disposal is also provided, aligning with environmental regulations.
General| Number of Inputs | 4 |
|---|---|
| Number of Outputs | 4 |
| Communication Protocol | Modbus RTU |
| Protection | IP20 |
| Outputs | Digital, Analog |
| Display | LCD |
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