IS200SRTDH2A - Compact RTD Terminal Board

Functional Description

IS200SRTDH2A is a compact RTD terminal board manufactured and designed by General Electric. It is a part of the Mark VIe series control system. The board stands as a specialized compact RTD terminal board, meticulously designed to be mounted either on a DIN-rail or a flat surface. The board is equipped with eight RTD inputs, providing a means to connect multiple RTDs, which are essential sensors for measuring temperature based on electrical resistance. The SRTD board connects to either the PRTD (Proportional RTD) or VRTD (Voltage RTD) I/O processor, forming an integral part of the system. It interfaces with the processor through high-density Euro-block type terminal blocks that are securely mounted onto the board.

Features

• On-Board Identification Chip: An ID chip integrated onto the board serves the purpose of identifying the board to the I/O processor. This identification aids in system diagnostics, enabling the processor to recognize and manage the SRTD board efficiently.
• Compatibility with Mark VIe Systems: In Mark VIe systems, the PRTD I/O pack collaborates seamlessly with the SRTD board. The I/O pack interfaces via a DC-37 pin connector and establishes communication with the controller through Ethernet connectivity. It's important to note that only simplex systems are supported, allowing for unidirectional communication or data flow.
• The PRTD I/O pack, when connected to the SRTD board, engages in communication with the controller via Ethernet, transmitting vital temperature-related data from the RTD inputs. This collaboration facilitates temperature monitoring and control within the system. The simplex system support ensures that the communication flow remains unidirectional, maintaining the system's reliability and simplicity.
• The board serves as a crucial component in temperature sensing and control systems, offering multiple RTD inputs and seamless compatibility with specific I/O processors, aiding in accurate temperature measurement and management within industrial setups.

Installation

• Mounting Options: The SRTD and a plastic insulator are assembled onto a sheet metal carrier designed to be mounted on a DIN rail. Additionally, there's an option where the SRTD and insulator can be affixed to a sheet metal assembly, which in turn can be bolted directly into a cabinet. These options offer flexibility in installation based on the specific setup requirements.
• Mounting the Components: The SRTD, along with the insulator, is securely attached to the designated sheet metal carrier or assembly, ensuring stability during operation. Mounting on a DIN rail or within a cabinet provides a stable and organized placement within the system.
• Wiring Setup: The eight RTDs (Resistance Temperature Detectors) are directly wired to the Euro-style box-type terminal block. This terminal block, equipped with 36 terminals and available in two types, serves as the central connection point for the RTDs.
  Typically, 18 AWG wires, specifically shielded twisted triplets, are used for wiring purposes. These wires help minimize interference and ensure accurate temperature readings.
• I/O Cable Shield Terminal: The shield terminal of the I/O cable utilizes an external mounting bracket supplied either by GE or provided by the customer. This bracket facilitates secure mounting of the shield terminal, enhancing the integrity of the shielded connections.
• Unused Terminals: Terminals 25 through 34 on the Euro-style box-type terminal block are intentionally left unconnected as part of the standard configuration or installation setup.
• Chassis Ground Connection: E1 and E2 serve as mounting holes specifically designated for the chassis ground screw connection (SCOM). Proper grounding of the SRTD board via these mounting holes ensures electrical safety and effective grounding practices within the system.

Operation

• Excitation Current for RTDs: The terminal board supplies a multiplexed (intermittent) excitation current of 10 mA DC to each RTD (Resistance Temperature Detector). This current can be configured as either grounded or ungrounded.
• Distance and Cable Resistance Limits: It allows for the connection of up to eight RTDs, located as far as 300 meters (984 feet) away from the turbine control cabinet. The system accommodates a maximum two-way cable resistance of 15 ohms.
• Noise Suppression and Signal Integrity: On-board noise suppression capabilities are integrated into the terminal board, akin to those present in the TRTD (Temperature RTD) system. These features ensure signal stability and minimize interference during temperature measurement processes.
• RTD Inputs and Signal Processing: The RTD inputs and subsequent signal processing mechanisms are depicted in the provided figure. This diagram illustrates how the RTD signals are received and processed within the system.
• Signal Sampling and Processing by PRTD Pack: The pack's A/D (Analog-to-Digital) converter samples each RTD signal and the excitation current at a rate of four times per second in normal mode scanning. In fast mode scanning, the sampling rate increases to 25 times per second, utilizing a time sample interval that corresponds to the frequency of the power system.
• Linearization and RTD Type Selection: The processor within the PRTD pack performs linearization processes for the selection of 15 different RTD types. This linearization ensures accurate temperature measurements and calibration, catering to the characteristics of various RTD types.