GE IC694ALG392 Analog Output Module for RX3i PACSystems
The GE IC694ALG392 is a versatile analog output module designed for the PACSystem RX3i platform. It provides eight single-ended output channels configurable for voltage or current signals. Engineers can select unipolar 0 to +10 volts or bipolar -10 to +10 volts for voltage outputs, and 0 to 20 milliamps or 4 to 20 milliamps for current outputs. Each channel offers 15- to 16-bit resolution depending on the selected range, ensuring fine granularity for precise control applications.
Technical Specifications and Performance
The module updates all channels individually every 8 milliseconds, making it suitable for fast-changing processes. Factory calibration achieves accuracy of 0.625 µA for 0 to 20 mA, 0.5 µA for 4 to 20 mA, and 0.3125 mV for voltage ranges per count. Absolute accuracy in voltage mode is ±0.25% of full scale at 25°C (typical) and ±0.5% maximum, with ±1.0% over the full operating temperature range. The module draws 110 mA from the +5 VDC backplane supply and 315 mA from a +24 VDC user supply. An external power source between 20 and 30 VDC (ideally 24 VDC) is required, with a maximum ripple of 10%.
Output Channels and Signal Types
Each of the eight channels can be independently configured for voltage or current output. When operating in current mode, the module detects open-wire faults and reports them to the CPU diagnostics. This feature helps maintenance teams quickly identify loose or removed wiring. Additionally, the module supports holding the last known value upon power loss or can reset to zero, depending on the configuration. This safety feature prevents erratic actuator behavior during system interruptions.
Resolution and Accuracy
The resolution varies by range: 4 to 20 mA offers 0.5 µA per LSB (16-bit effective), 0 to 20 mA provides 0.625 µA per LSB (15-bit), and both voltage ranges deliver 0.3125 mV per LSB (16-bit). The high resolution allows precise control of valves, motors, pistons, and agitators. The module is factory-calibrated, ensuring consistent performance across all channels.
Power and Compatibility
The GE IC694ALG392 integrates seamlessly with Series 90-30 and 90-70 PLCs, as well as RX3i PACSystems. It receives 5 VDC power from the backplane and requires an external 24 VDC supply for loop power. The module automatically adapts its power consumption based on the supply source. Users must provide environmental protection due to the system's low IP rating; moisture and extreme temperatures can affect reliability.
Applications and Integration
This analog output module is ideal for modulating control loops beyond simple on/off actions. It can link internally to the controller's PID algorithm for automatic regulation or interface with manual loaders for manual mode. Typical applications include controlling actuators, re-transmitting signals to data loggers, and connecting to measuring instruments, totalizers, converters, and isolators. The module's 8-millisecond update rate makes it excellent for fast-paced industrial processes.
Conclusion
The GE IC694ALG392 offers engineers a reliable, high-resolution analog output solution for RX3i PACSystems. With flexible signal ranges, open-wire detection, and fast update rates, it meets the demands of precise process control. Proper external power and environmental protection ensure long-term performance in harsh industrial environments.