The IS200STAOH2A is a compact, high-performance Simplex Analog Output Terminal Board designed for use with the PAOC Analog Output Module to provide precise current control for field devices. This terminal board supports eight independent 0–20 mA analog current output channels, making it suitable for industrial control systems requiring high analog signal integrity in space-constrained environments. The IS200STAOH2A features a high-density Euro-block terminal design, supports DIN-rail or panel mounting, and offers excellent noise suppression and surge protection capabilities, making it well-suited for harsh industrial applications.
II. Key Features
1. High-Density Structure and Mounting Flexibility
The IS200STAOH2A boasts a compact design measuring 15.9 cm high × 10.2 cm wide, effectively saving space within control cabinets. It supports two mounting methods:
DIN-rail Mounting: Can be assembled with an insulator for mounting on standard rails, facilitating modular installation.
Panel Mounting: Can be fixed directly inside a control cabinet using a metal carrier.
The IS200STAOH2A is equipped with a removable 36-pin Euro-block terminal block, simplifying field wiring and maintenance. Compared to the fixed terminal block of the IS200STAOH1A, the removable design of the IS200STAOH2A offers significant advantages during maintenance operations.
2. Electrical Characteristics and Load Capacity
Output Type: 8 single-ended 0–20 mA current output channels.
Load Capacity: Maximum load resistance of 900 Ω per channel, with output voltage compliance up to 18 V.
Transmission Distance: Supports distances up to 300 meters (984 feet), suitable for controlling remote actuators.
Noise Suppression: Each output channel is equipped with a high-frequency noise filter and surge suppression circuit, effectively preventing electromagnetic interference and transient overvoltage damage.
3. Diagnostics and Identification Features
Current Feedback Monitoring: The output current for each channel is monitored via a 50 Ω sense resistor on the terminal board. The resulting voltage signal is read by the PAOC module's 16-bit ADC, ensuring output accuracy and health monitoring.
Electronic ID Recognition: The terminal board contains a read-only ID chip programmed with the board type, serial number, revision number, and connector location information. The PAOC module reads this ID during startup. If a mismatch with the system configuration is detected, a hardware incompatibility fault is generated.
4. Compatibility and System Integration
Interfaces directly with the PAOC Analog Output Module via a D-type connector.
Compatible with the Mark VIe control system, communicating with the controller via IONet Ethernet.
Supports simplex operation only; redundant operation is not supported.
III. Functional Principles (Detailed)
1. Signal Generation and Output Control
The IS200STAOH2A itself does not generate analog signals; the output current is generated and driven by the PAOC module. Internally, the PAOC module uses a 16-bit Digital-to-Analog Converter (DAC) to convert digital commands from the controller into precise analog current signals. These signals are transmitted via the D-type connector to the IS200STAOH2A terminal board and then routed through the terminal block to field actuators (e.g., valve positioners, variable frequency drives).
Within the PAOC module, each output channel includes a linear output drive circuit ensuring accurate current control within the 0–20 mA range. The output stage also includes a "Suicide Relay." If an output anomaly is detected (e.g., current over-limit, communication loss), this relay automatically opens, disconnecting the output to prevent misoperation or device damage.
2. Current Feedback and Health Monitoring
Each output channel on the IS200STAOH2A employs a 50 Ω precision sense resistor to convert the output current into a voltage signal. This signal is fed back to the PAOC module and sampled by its internal 16-bit ADC. The PAOC compares the sampled value against the expected output value. If the deviation exceeds the configured D/A_ErrLimit threshold, an "Output Feedback Unhealthy" alarm is triggered.
This "closed-loop monitoring" mechanism ensures the system can detect the following anomalies in real-time:
Open or short circuit on the output line.
Excessive load resistance.
DAC or output drive circuit failure.
Loose wiring or poor connections.
3. Noise Suppression and Protection Mechanisms
The IS200STAOH2A incorporates an RC filter network at each output to suppress high-frequency noise. Additionally, the board includes Transient Voltage Suppression (TVS) components to absorb surge voltages originating from the field environment (e.g., lightning strikes, inductive load switching), protecting the connected PAOC module from damage.
4. Communication and Diagnostic Integration
The IS200STAOH2A facilitates data exchange with the controller via the PAOC module's Ethernet communication. The following parameters can be configured and monitored using the ToolboxST software:
Output range scaling (Low_MA / High_MA).
Suicide relay enable/disable (Suicide_Enab).
Output behavior during communication loss (Hold Last Value / Power Down Mode / Predefined Output_Value).
Dither settings (DitherAmpl / Dither_Freq).
All diagnostic information (e.g., output status, relay feedback, board temperature) can be viewed in real-time within ToolboxST. Triggered diagnostic latches can be reset using the RSTDIAG signal.
IV. Installation and Wiring Instructions
1. Installation Steps
Assemble the IS200STAOH2A with its insulator and mount it onto a DIN-rail or panel.
Install the PAOC module onto the terminal board's D-type connector using the provided side mounting brackets.
Secure the PAOC module using the threaded studs adjacent to the Ethernet ports, ensuring no right-angle force is applied to the D-type connector.
Connect the Ethernet cables (ENET1/ENET2) and the 28 V DC power supply.
2. Wiring Guidelines
Use #18 AWG shielded twisted pair cables for field wiring.
Each output channel consists of a "Signal" and a "Return" terminal.
The system common (SCOM) is grounded via the E1/E2 chassis ground screw connection.
A dedicated shield terminal strip is not provided with this design; cable shields must be grounded using an external grounding bracket supplied by GE or the customer.
