GE IC695ALG728-CB 8-Channel Non-Isolated Analog Voltage/Current Output with HART

Description

In modern process control and industrial automation systems, engineers frequently deal with smart field devices like control valves, positioners, and actuators that support HART protocol for digital configuration, diagnostics, and multi-variable data alongside traditional analog signals. Without integrated HART capability, this requires separate communicators, multiplexers, or handheld devices—adding complexity, wiring, and potential points of failure while limiting real-time access to device health in the control loop.

The GE IC695ALG728-CB addresses these challenges by combining eight high-density analog output channels with built-in HART communications in a single RX3i slot. Each channel is individually configurable for voltage (±10V, 0-10V) or current (0-20mA, 4-20mA) outputs, and with two internal HART modems, it supports simultaneous digital overlay on up to eight devices (multiplexed). This enables direct pass-through of HART data to asset management software or the control logic, providing device status, calibration, and diagnostics without interrupting the primary 4-20mA control signal.

The GE IC695ALG728-CB becomes essential in upgrades to PACSystems RX3i where legacy analog outputs need enhanced smart device integration, in plants adopting predictive maintenance strategies, or in modular setups requiring high reliability for I/O signals amid expanding fieldbus adoption. It excels in process control environments demanding signal reliability, reduced commissioning time, and ongoing visibility into field instrument performance in industrial automation applications.

The GE IC695ALG728-CB slots directly into the RX3i universal backplane, leveraging the high-speed PCI bus for rapid data exchange with the CPU. Outputs are sourced from the module’s onboard DACs, with per-channel configuration handled in Proficy Machine Edition—setting range, scaling, alarms, and HART enablement.

With HART active, the two modems time-share across enabled channels, allowing commands to pass through via PROFINET (when using compatible controllers) or direct logic access. Diagnostics include open-loop detection, over/under range alarms, and HART-specific status like device response timeouts, reported via status bits and front-panel LEDs for module health, configuration, and individual channel faults.

In the automation stack, it positions as a smart analog output layer, complementing non-HART modules like the ALG708 for basic loops while adding digital intelligence for valve positioners or variable speed drives. It supports hot insertion and works with any recent RX3i CPU, making it straightforward to layer HART capability onto existing I/O architecture without external gateways.

Opting for the GE IC695ALG728-CB brings immediate reliability through robust analog performance combined with HART’s diagnostic depth, ensuring consistent loop control while flagging device issues early—preventing unplanned outages in critical processes. Engineered for demanding environments, it maintains high accuracy (typically 0.1% of full scale) and fast update rates, delivering long-term performance where signal drift or undetected valve faults could impact throughput.

Maintenance efficiency gains are significant: built-in diagnostics and HART pass-through reduce the need for separate field trips, while alarm latching and status reporting streamline troubleshooting. Integration overhead drops substantially—no extra multiplexers or software layers required beyond standard Proficy tools, allowing teams to focus on logic rather than communication setup.

In operation, the value emerges as lower lifecycle costs: fewer devices to manage, better asset utilization through real-time HART data, and easier compliance reporting. The GE IC695ALG728-CB provides engineers with a dependable platform that bridges traditional analog control and modern digital field instrumentation seamlessly.

The GE IC695ALG728-CB is commonly deployed in oil and gas production facilities for controlling smart valve positioners on separators or injection skids, where HART diagnostics support predictive maintenance under harsh conditions and ensure critical system uptime.

Chemical processing plants use it extensively in batch reactors and distillation columns for precise dosing via current loops with overlaid HART for valve health monitoring in continuous operations.

Power generation applications, including combined cycle plants, incorporate it for fuel valve control and damper actuation, delivering noise-immune signals and device status in electrically challenging environments with demands for fast response and regulatory traceability. In pharmaceuticals, water treatment, and food processing, the GE IC695ALG728-CB shines where process control environments require high reliability, smart device integration, and uninterrupted data cycles.

IC695ALG728-DC – Later revision with potential firmware enhancements and improved manufacturability IC695ALG728-BB – Previous standard revision for compatible systems IC695ALG728-LT – Extended low-temperature variant for colder environments IC695ALG708-CB – 8-channel non-HART analog output for basic voltage/current needs IC695ALG808 – 8-channel isolated analog output without HART IC695ALG628 – 8-channel HART-capable analog input module IC695ALG704 – 4-channel non-isolated analog output for lower density IC695ALG508 – Isolated output module for higher isolation requirements

Prior to installing the GE IC695ALG728-CB, ensure your RX3i backplane is universal and the CPU firmware supports HART features if pass-through is planned—check compatibility with PROFINET controllers for full functionality. Calculate power budget carefully, including external 24V supply for field loops if sourcing higher currents.

Use high-density terminal blocks and plan wiring with proper loop isolation in mind, as channels are non-isolated—common returns are acceptable for grounded devices. Test HART communication in Proficy with a simulator or known device during configuration to verify modem operation before field connection.

For routine maintenance, monitor LED indicators and diagnostic bits for HART response issues or loop faults, and periodically validate outputs with a calibrator. Inspect terminals for secure connections in vibrating settings, and maintain a configured spare with your typical range and HART settings for rapid replacement—minimizing disruption in operational plants.