Description
Key Technical Specifications
- Output Channels: 4 isolated channels
- Voltage Output Range: 0-10VDC (configurable per channel)
- Current Output Range: 4-20mA (configurable per channel)
- Resolution: 12-bit (4096 counts)
- Accuracy: ±0.25% of full scale at 25°C
- Voltage Load Impedance: 1KΩ (min) to 5KΩ (max)
- Current Load Resistance: Maximum 600Ω @ 24VDC supply
- Update Rate: 1 ms (all 4 channels)
- Isolation: 1500 VAC per channel
- Backplane Current: 200 mA @ +5VDC
- External Power: 24VDC required for 4-20mA outputs
IC693ALG220
4. Product Introduction
This module provides four isolated analog output channels for Series 90-30 PLCs, configurable per channel as either 0-10VDC voltage or 4-20mA current outputs. Each channel independently drives field devices through optical isolation, protecting the backplane from ground loops and common-mode noise. The digital-to-analog converters deliver 12-bit resolution with ±0.25% accuracy, adequate for most process control applications.
The key advantage is per-channel configurability and isolation. You can mix voltage and current outputs on the same module to drive diverse field devices—VFDs needing 0-10V references, valve positioners requiring 4-20mA signals—all from one 4-channel card. Channel-to-channel isolation eliminates ground reference conflicts when devices share different power sources or ground potentials.
5. QA & Testing SOP
Our QC process follows a rigorous 5-step protocol to ensure every unit performs to spec:
1. Incoming Inspection: We verify part numbers and examine for physical damage—heat discoloration, bent pins, corrosion, counterfeit markings. We trace lot numbers against GE/Emerson datasheets to confirm manufacturing origin.
2. Live Testing: The unit powers up in a Series 90-30 test rack. We load each channel at 0%, 50%, and 100% output levels. A Fluke 87V multimeter verifies voltage outputs within ±0.25% and current outputs within ±0.25%. All 4 channels execute simultaneously for 4 hours.
3. Electrical Testing: Insulation resistance exceeds 10MΩ between channels and backplane (measured at 500VDC). We verify continuity on all backplane pins and check for short circuits between adjacent channels.
4. Firmware/Config Backup: For reprogrammable modules, we record the exact firmware version. Photo documentation captures any DIP switch positions or jumper configurations before testing begins.
5. Final QC & Packaging: The module passes final visual inspection, receives a QC pass tag, and ships in anti-static packaging. Each unit includes a test report documenting measured values at each output point.
6. Installation Pitfalls & Guide
❗ Forgetting External 24VDC for Current Outputs
Current outputs (4-20mA) require external 24VDC power connected to the module’s power input terminals. Without this, current outputs won’t drive and LEDs stay dark. Voltage outputs use backplane +5VDC and don’t need external power.
❗ Exceeding Load Resistance Limits
Current outputs can drive maximum 600Ω at 24VDC supply. Wiring a 1000Ω load causes saturation—you’ll get less than expected current. For 0-10V outputs, loads must stay within 1KΩ-5KΩ or accuracy degrades.
❗ Mixing Isolated Channel Commons
Each channel is isolated for a reason. Tying commons together between channels creates ground loops. Use separate commons per channel unless you’ve verified all field devices share exactly the same ground reference.
❗ Wiring Polarity Backwards on Current Loops
Reversing polarity on 4-20mA outputs can damage field devices. Observe terminal markings (+/-) and verify polarity with a multimeter during commissioning.
❗ Skipping Calibration Verification
Factory calibration can drift. Verify each channel with a multimeter at minimum, mid-scale, and maximum before commissioning. If accuracy is outside ±0.25%, the unit needs recalibration or replacement.
4-Step Replacement Guide:
- Pre-install: Document channel configuration (voltage vs. current per channel) and photograph the terminal block wiring.
- Removal: Power down the rack. Disconnect the terminal block. Remove the failed module.
- Install: Install the replacement module. Reconnect the terminal block.
- Power-on Test: Apply power. Verify each channel outputs the correct value using a multimeter. Check LED indicators illuminate above minimum output thresholds.
IC693ALG220
7. FAQ
Q: Does this module support hot-swapping?
A: No. GE IC693ALG220K is not rated for hot-swap. Removing it with power applied risks backplane communication faults and potential module damage. Always power down the rack before replacement.
Q: Can I mix 0-10V and 4-20mA outputs on the same module?
A: Yes, per-channel configurability allows mixing. However, if any channel is configured for 4-20mA, you must connect external 24VDC power to the module. Voltage outputs don’t require external power, but current outputs do.
Q: What happens if a current loop opens (wire breaks)?
A: The live zero (4mA floor) provides fault detection. Current drops below 4mA, and the field device can detect an open circuit. Many control valves drive to a safe position when input falls below 4mA. Implement PLC logic to monitor for below-4mA conditions.
Q: Is this module still manufactured?
A: The Series 90-30 platform is mature. While GE/Emerson may still offer limited support, most available units are New Surplus or refurbished stock. Verify firmware compatibility with your existing modules before installation.
Q: Will this module work in a Series 90-70 rack?
A: No. IC693ALG220K is designed specifically for Series 90-30 backplanes. Mechanical and electrical interfaces differ between Series 90-30 and 90-70. You need Series 90-70 specific modules (IC697ALGxxx series) for 90-70 racks.
Q: Does replacing this module erase configuration?
A: The module itself doesn’t store channel configuration—that’s handled in the PLC program. However, if your PLC relies on configuration data stored in the module (rare for this model), backup that data before removal. For this specific module, configuration is typically per-channel in the PLC logic, not the module itself.
