Key Technical Specifications
| Parameter | Specification |
|---|---|
| Input Channels | 10 Total (8 Configurable, 2 Dedicated) |
| Input Config | 5V, 10V, or 4-20 mA (Ch 1-8); 1mA or 4-20mA (Ch 9-10) |
| Output Channels | 2 Current Loop Outputs (0-20 mA) |
| Extended Output | Ch 1 supports 0-200 mA hardware option |
| Interface | Single DC-37 Pin Connector to Terminal Board |
| Network | Dual RJ-45 Ethernet (ENET1/ENET2) |
| Power | 3-Pin Connector, Soft-Start Current Limiting |
| Processor | BPPx Processor Board + Acquisition Board |
| Diagnostics | Front Panel LED Status Indicators |
| Mounting | Direct Plug-in with Mechanical Stud Lock |
Product Introduction
Analog I/O in turbine control is where most field wiring headaches start. You’ve got 4-20mA loops, voltage signals, and ground loops all fighting for space in a cramped terminal board. The GE IS220PAICH2A (336A4940CSP11) is the Mark VIe’s answer to this mess. It’s not just a card; it’s a complete analog acquisition pack that plugs directly into the terminal board via a single DC-37 connector. No ribbon cables, no separate backplane wiring for the I/O itself.I’ve installed dozens of these in retrofits. The real value is the flexibility. Channels 1 through 8 can be software-configured for voltage or current, while the last two are dedicated low-current inputs. The 0-200mA output on channel 1 is a lifesaver when you need to drive a high-impedance valve positioner without adding a separate relay. Just be careful with the Ethernet cables; the dual RJ-45s are for redundancy, but I’ve seen techs plug them into the same switch port and wonder why the system doesn’t see the link. It’s a solid, compact pack, but it demands clean termination at the DC-37 connector.
Quality SOP & Tech Pitfalls
We don’t just ship these in a box and hope. Every IS220PAICH2A gets a visual inspection for bent DC-37 pins and corrosion on the RJ-45 jacks. Then it goes on a Mark VIe test rack. We inject 4-20mA signals into all 10 channels and verify the acquisition board reads within spec. We also check the soft-start circuit by monitoring inrush current during power-up. If it spikes, it’s rejected. Finally, we log the hardware revision and seal it.Here is the trap: The DC-37 connector is fragile. I’ve seen guys force the I/O pack onto the terminal board at an angle because they didn’t align the guide pins. Result? Bent pins, intermittent signals, and a $2,000 headache. Always use the mechanical studs to pull the pack flush; never hammer it. Also, verify your terminal board type. The IS220PAICH2A needs the correct TMR or simplex terminal board. Plug it into a digital I/O board, and you’ll fry the acquisition circuit instantly.
Installation & Configuration Guide
- Pre-Installation: ⚠️ Verify the terminal board part number matches the PAIC pack. Take a photo of the existing DC-37 wiring harness. Ensure the Ethernet cables are labeled ENET1 and ENET2.
- Removal: Disconnect the 3-pin power connector first. Loosen the two mechanical mounting studs. Pull the pack straight out; do not wiggle side-to-side.
- Installation: Align the DC-37 connector perfectly with the terminal board. Push evenly until seated. Hand-tighten the mechanical studs to lock it. Do not overtighten. Connect the 3-pin power; the soft-start will handle the inrush.
- Power-On & Testing: Apply power. Check the front LEDs; you should see a steady green status within 30 seconds. Open ToolboxST and verify the I/O pack is recognized. Run a loop test on Channel 1 to confirm the 4-20mA output is accurate.
Compatible Replacement Models
| Model | Compatibility Tier | Notes |
|---|---|---|
| IS220PAICH2A | ✅ Drop-in Replacement | Exact match for 336A4940CSP11. Direct swap. |
| IS220PAICH1A | ⚠️ Software Compatible | Single-channel output version. Requires ToolboxST reconfiguration. Check if you need the 2nd output. |
| IS220PAICH2B | ✅ Drop-in Replacement | Minor revision. 100% backward compatible. Verify firmware compatibility in ToolboxST. |
Frequently Asked Questions (FAQ)
Can I use this pack with a simplex terminal board?
Yes, but only if it’s the correct simplex board designed for PAIC packs. Some simplex boards are for digital I/O only. Check the terminal board part number. The IS220PAICH2A will physically fit, but electrically it might not work.What happens if I lose one Ethernet link?
Nothing. The dual RJ-45s are for redundancy. As long as ENET1 or ENET2 is connected to the controller network, the pack stays online. The LEDs will show which link is active. I’ve seen plants run for years on a single cable because the second one was never terminated.Do I need to configure the 4-20mA load resistors?
No. The load resistors are on the terminal board, not the I/O pack. The IS220PAICH2A just measures the voltage drop across them. If your current reading is off, check the terminal board resistors for drift, not the pack.Is the 0-200mA output always available?
Only on Channel 1. And it requires the specific hardware option. If you order a standard pack and try to pull 100mA from Channel 1, it will current-limit and throw a fault. Check the nameplate or ordering code for the “200mA” option.Can I hot-swap this module?
Technically, the soft-start allows it, but don’t. Mark VIe doesn’t officially support hot-swapping analog packs. You risk corrupting the I/O configuration or causing a transient spike on the field wiring. Kill the power, swap the pack, and restart. It takes 5 minutes. Not worth the risk.Why does ToolboxST show a “Comm Fault” after replacement?
You probably didn’t lock the mechanical studs. The DC-37 connector needs firm, even pressure to maintain contact. If the pack is slightly cocked, the high-speed Ethernet signals will drop. Reseat the pack, tighten the studs evenly, and reboot. 9 times out of 10, that fixes it.
