Description
Product Introduction & Engineering Value
When you’re tuning precise control loops—like positioning a heavy-duty hydraulic actuator or throttling a critical steam valve—jittery analog output resolution can ruin product quality. The GE PACSystems RX3i IC694ALG392 steps in with 8 software-configurable analog channels, giving you clean 15-bit resolution across both voltage and current ranges without touching a single hardware jumper.
Engineered to operate on the high-speed RX3i PCI backplane, this card processes setpoint conversions fast—updating all eight output channels in under 8 milliseconds. It offloads scaling tasks directly to local hardware, letting the main CPU write engineering units straight to %AQ registers while maintaining steady signal outputs even during transient processor reboots.
Technical Specifications
| Parameter | Specification Details |
| Output Channels | 8 Single-Ended/Grouped Channels |
| Output Ranges (Current) | 0 to 20 mA, 4 to 20 mA |
| Output Ranges (Voltage) | 0 to +10 VDC, -10 to +10 VDC |
| D/A Resolution | 15-bit (1 part in 32,768) |
| Update Rate | 8 ms max for all 8 channels |
| Current Loop Compliance | 0 to 850 Ohms @ 24 VDC external loop supply |
| Voltage Load Resistance | 2,000 Ohms minimum load |
| Backplane Power | 110 mA @ 5 VDC |
| User External Power | 24 VDC ± 10% (requires 216 mA maximum) |
| Diagnostics | MODULE OK and USER SUPPLY front panel status LEDs |
Field Application & The “Trench” Experience
The Trench Story: A municipal wastewater facility ran into a critical fault during a storm surcharge event when Channel 3 on an aging output card failed high, locking an influent bypass damper wide open. The maintenance crew grabbed a surplus IC694ALG392, unclipped the 36-pin terminal block without pulling field wiring, snapped the module onto the RX3i baseplate, and uploaded the original PAC Machine Edition hardware profile. The new card immediately took over, restoring 4–20 mA loop control to the damper actuator in under 20 minutes.
- Variable Frequency Drive (VFD) Speed Reference: Commanding multiple pump motors via 4–20 mA velocity setpoints across water treatment trains.
- Proportional Steam Control Valves: Delivering 0–10V positioning signals to boiler feed valves requiring smooth 15-bit step transitions.
- Chemical Dosing Pump Control: Precise milliamp pulsing for acid/caustic neutralizer dosing systems in industrial wastewater treatment.
- IC694ALG392
- IC694ALG392
Transparency SOP: QA & Testing
- Physical Inspection: Checking backplane card-edge contacts, guide rails, terminal latching mechanics, and case housing integrity.
- Backplane & User Supply Power-Up: Plugging into an RX3i baseplate (IC695CHS012) under 24 VDC external field power to verify
MODULE OKandUSER SUPPLYstatus illumination. - 8-Channel DAC Calibration Test: Driving all 8 channels through step commands (4mA, 8mA, 12mA, 16mA, 20mA / -10V, 0V, +10V) using a Fluke 773 process meter to confirm output linearity within 0.1% full scale.
- Loop Impedance Load Testing: Simulating realistic field load profiles (stepping resistance from 100 to 750 Ohms on current loops) to verify current regulation stability.
- Holding-State & Fail-Safe Test: Testing channel behavior under simulated CPU stop states to verify configured Default/Hold Last State behaviors.
The Veteran’s Tech Trap Guide
⚠️ Missing 24 VDC External User Power: The MODULE OK LED might glow green from backplane power alone, but if your external 24 VDC supply isn’t wired to terminals 35 and 36, the USER SUPPLY LED will stay dark and all outputs will sit dead at 0 mA or 0 V. Always verify user supply voltage directly across the terminal block.
⚠️ Configuring Default/Hold Values: In PAC Machine Edition, you can set channels to either drop to 0mA/0V or HOLD their last known state if the PLC CPU enters STOP mode. For critical valves or burners, setting this wrong can result in runaway conditions during a routine CPU pause. Always review the “Output State in STOP” hardware settings before putting the rack live.
PRO TIP: Need to drive a 4–20 mA loop with high line resistance? Make sure your external 24 VDC field supply stays above 21.6 VDC under full 8-channel load. If voltage sags, channels trying to drive 20 mA into high-impedance loops (>600 Ohms) will clip and freeze at a lower output limit.
Dynamic FAQ
Q: Can I mix voltage and current outputs on the same IC694ALG392 module?
A: Yes. Each of the 8 channels is configured independently inside PAC Machine Edition software. You can set Channel 1 to 4–20 mA for a VFD reference, Channel 2 to -10/+10V for a servo positioner, and Channel 3 to 0–10V without issue.
Q: What happens if an external wire snaps on a 4–20 mA output channel?
A: While voltage outputs tolerate open circuits, an open loop on a current channel stops loop current completely. The IC694ALG392 detects low compliance voltage conditions and generates a diagnostic fault flag in %I status memory, enabling your PLC code to sound an alarm.
Q: Is the directly backward-compatible with older GE Series 90-30 systems?
A: No. The uses the PACSystems RX3i backplane interface and is built for RX3i universal baseplates. For legacy Series 90-30 racks, you would typically look for the IC693ALG392 module.
Q: What is the lead time and warranty on your surplus stock?
A: Our fully bench-tested New Surplus and Refurbished units are ready in stock for immediate same-day dispatch, backed by a complete replacement warranty and shipped in ESD anti-static packaging.
Start Chat
