IS220PAOCH1A, REV F - Analog Output I/O Module

SPECIFICATIONS:

Part Number: IS220PAOCH1A, REV F
Manufacturer: General Electric
Series: Mark VIe
Product Type: Analog Output I/O Module
Number of channels: Eight current output channels
Analog Outputs: 0-20 mA, up to 900 Ω
Accuracy: ±0.5% over -30 to 65oC (-22 to 149 oF) temperature
Size: 8.26 cm high x 4.19 cm wide x 12.1 cm
Operating Temperature: -30 to 65°C
Availability: In Stock
Country of Origin: USA
Manual: GEH-6721D

FUNCTIONAL DESCRIPTION:

IS220PAOCH1A, REV F is an Analog Output I/O Module manufactured and designed by General Electric as part of the Mark VIe Series used in Distributed Turbine Control Systems. The PAOC is the electrical interface between one or two I/O Ethernet networks and an analog output terminal board. It includes a shared processor board used across all Mark VIe distributed I/O packs, along with a specialized acquisition board for analog output. The unit supports up to eight simplex 0–20 mA current loop outputs and features an analog-to-digital converter for current feedback on each channel. It accepts input through dual RJ45 Ethernet ports and a three-pin power connector, while output is delivered via a DC-37 pin connector that links directly to the terminal board. Diagnostic LEDs provide visual status, and an infrared port enables local serial communication for diagnostics.

PAOC COMPATIBILITY:

The PAOCH1A is designed for use with the TBAOH1C analog output terminal board and the STAO board, but is not compatible with the DIN-rail mounted DTAO board. Control mode defines the number of I/O packs in a signal path:

• Simplex: one I/O pack with one or two network connections
• Dual: two I/O packs with one or two network connections
• TMR (Triple Modular Redundant): three I/O packs, each with a single network connection.

Although the PAOC can be physically mounted on TBAOH1A or TBAOH1B boards, it will not achieve full analog signal accuracy due to circuit differences in those revisions. Therefore, it is only fully compatible with the TBAOH1C version. If connected to an earlier version, the PAOC will detect and report a compatibility issue, but no hardware damage will occur from incorrect installation.

PAOC I/O PACK INSTALLATION:

• Connect the PAOC I/O pack(s) directly to the terminal board using the DC-37 pin connector.
• Secure the I/O pack(s) by fastening them with the threaded studs located near the Ethernet ports. These studs align with a mounting bracket designed specifically for the corresponding terminal board style.
• Ensure the bracket is positioned to avoid placing lateral stress on the DC-37 connector during installation. This alignment typically needs adjustment only once during the product's operational life.
• Depending on the system configuration, attach one or two Ethernet cables. Either Ethernet port on the I/O pack can be used. In dual configurations, ENET1 is typically connected to the network associated with the R controller.
• Attach the power cable to the side connector of the PAOC to supply power. The built-in soft-start feature manages inrush current during power-up, so disconnecting power before connection is not required.

OPERATION:

The processor board is paired with an acquisition board tailored to the specific function of the I/O pack. When input power is applied, a soft-start circuit gradually increases the voltage supplied to the processor board. This initiates a sequence where the local power supplies are activated, and the processor reset is cleared.
Following this, the processor performs self-diagnostic checks and loads the appropriate application code from flash memory based on the I/O pack type. It then verifies compatibility by reading identification data from both the acquisition board and the terminal board to confirm proper alignment with the loaded code.

If the components match correctly, the processor initiates Ethernet communication by requesting a network address via the standard DHCP protocol, using a unique identifier obtained from the terminal board. Once the Ethernet setup is complete, the processor configures internal logic, starts the application, and activates the acquisition board to begin normal operation.

• High-speed processor with RAM and flash memory
• Two fully independent 10/100 Ethernet ports with connectors
• Hardware watchdog timer and reset circuit
• Local ambient temperature sensor
• Infrared serial communications port
• Status-indication LEDs
• Electronic ID and the ability to read IDs on other boards
• Substantial programmable logic supporting the acquisition board
• Input power connector with soft start/current limiter
• Local power supplies, including sequencing and monitoring

ANALOG OUTPUT HARDWARE:

The PAOC features eight simplex analog outputs, each providing 0–20 mA with 18 V compliance. A 16-bit digital-to-analog converter (DAC) manages and drives an external transistor amplifier, which regulates the output current.

To monitor internal conditions, a built-in temperature sensor detects excessive heat and alerts the control system if necessary. Each output channel includes a mechanical, normally open relay that governs whether the output is active. When the relay is de-energized, it interrupts the connection between the PAOC analog output and the external load connected to the terminal board.

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FREQUENTLY ASKED QUESTIONS:

What is the function of the Analog Output I/O Module (PAOC)?

The PAOC provides up to eight simplex 0–20 mA analog outputs used for controlling external devices. It interfaces between the control system and field equipment via a terminal board.

Which terminal boards are compatible with the PAOC?

The PAOC is fully compatible with the TBAOH1C terminal board and the STAO board. It is not compatible with the DTAO DIN-rail mounted board. Although it can be mounted on TBAOH1A or TBAOH1B, it will not achieve full signal accuracy on these older revisions.

How does the PAOC regulate analog output?

Each channel uses a 16-bit DAC to control an external transistor amplifier. The current output is then managed based on the DAC's input values.