Quick Sizing & Sourcing Snapshot
- Manufacturer: GE Fanuc (Emerson Machine Automation Solutions)
- Part Number: IC697CHS750
- System Platform: Series 90-70 PLC / PACSystems RX7i
- Hardware Type: 5-Slot Rear-Mount I/O Rack (Chassis)
- Architectural Role: Provides the mechanical mounting frame and VME-based backplane bus for 5 IC697 modules and 1 Power Supply, distributing 5V DC power and high-speed parallel data signals between cards.
- Key Specifications: 5 I/O Slots, 20A @ 5V DC Backplane, Rear-Mount, 254mm Depth.
System Architecture & Operational Principle
The is a passive mechanical chassis and backplane assembly, sitting at Purdue Level 1/2 (depending on if it holds a CPU or just I/O). It is designed specifically for the GE Fanuc Series 90-70 ecosystem (and forward-compatible with RX7i).
Physically, it is a “Double-Width” rack (occupying 12 inches of horizontal panel space) intended for Rear-Mount installation. This means the metal frame bolts to the back of a control panel cutout, with module fronts (LEDs/Wiring) facing the operator, and field cables entering from behind the panel via a hinged access door.
Upstream, it receives 120/240V AC or 125V DC via an IC697PWR711/PWR720 Power Supply module plugged into the dedicated top slot. The PSU converts this to 5V DC (and +/-12V on some models) which is distributed along the VMEbus Backplane (P1/P2 connectors) to all 5 I/O slots.
Downstream, it hosts a mix of IC697 modules: CPUs (IC697CPU771/772), Discrete I/O (IC697MDLxxx), Analog I/O (IC697ALGxxx), and Communications (IC697CMMxxx). The backplane uses the proprietary VMEbus parallel architecture for inter-card communication. It supports daisy-chaining up to 8 racks total in a system using expansion cables, making it a staple for distributed I/O in large process skids (e.g., Boiler Burner Management).
Core Technical Specifications
- Slot Count: 5 I/O Slots (Plus 1 dedicated Power Supply Slot)
- Mounting Style: Rear-Mount (Panel Cutout), Vertical Orientation Only
- Backplane Bus: VMEbus (Parallel, P1/P2 Connectors)
- Power Rating: 5V DC @ 20A (100W) Backplane Distribution
- Dimensions (H x W x D): 11.15″ x 12.60″ x 7.5″ (283 x 320 x 190 mm)
- Enclosure Depth: 254 mm (10 inches) – Requires deep cabinet
- Wire Capacity: Up to 40 x #14 AWG wires via bottom cavity/door
- Cooling: Passive Convection (Front-to-Rear airflow, no fans)
- Expansion: Supports J2 Backplane Kit for extended signaling
- Material: Heavy-Gauge Steel / Aluminum (Double-Width frame)
- Environmental: 0°C to +60°C, 5-95% RH (Non-Condensing), IP20
Customer Value & Operational Benefits
Clean Panel Aesthetics (Rear-Mount)
The “Rear-Mount” design is the primary value for OEM skids and food-grade plants. By bolting the rack to the backof the panel, you keep the field wiring (terminal blocks) hidden behind the wall, leaving only the module faces (LEDs, removable front connectors) visible to the operator. This prevents fork trucks from snagging wires and keeps washdown spray off terminal blocks, cutting panel cleaning time by 30% and reducing inadvertent wire pulls during maintenance.
High-Current Backplane (20A)
Unlike flimsy DIN-rail carriers, this rack’s backplane is a thick, plated PCB distributing 5V @ 20A. This supports high-density Analog Input cards (e.g., IC697ALG230 x 5 = 16 channels each) without voltage drop. You avoid adding external 5V power distro blocks, saving 2-3 DIN slots per rack and ensuring the CPU sees stable 5V even during cold-start inrush.
VMEbus Data Throughput
The parallel VME backplane ensures deterministic, low-latency data exchange between the CPU (Slot 1) and I/O cards (Slots 2-5). In high-speed packaging lines or turbine vibration monitoring (using IC697HSC115), this beats serial backplanes (like Profibus/TCP) for scan time consistency, preventing “missed counts” or jitter in motion loops.
