GE IC693CPU363 | Modular CPU 240K Base – Series 90-30 – Field Service Notes

Description

Hard-Numbers: Technical Specifications

• Processor: Intel 80486DX4, 25 MHz clock
• User Program Memory: 80 KB
• Register Memory: 240 KB (%R addressing)
• Floating Point: Supported (32-bit hardware)
• Discrete I/O: 2048 points max combined (%I + %Q)
• Analog Input (%AI): 128 words (up to 8K with option modules)
• Analog Output (%AQ): 64 words (up to 8K with option modules)
• Internal Coils (%M): 1024 bits
• Discrete Global Memory (%G): 1280 bits
• Timers/Counters: 340 combined
• Scan Rate: 0.22 ms per 1K Boolean logic (typical)
• Serial Ports: 2 (Port 1: SNP/X master/slave, Port 2: SNP/X master/slave)
• Baud Rate: Up to 115.2 Kbaud
• Ethernet Port: 1 x RJ-45 10/100 Mbps auto-sensing
• Ethernet Protocols: SRTP, Modbus TCP (Master/Slave), Ethernet Global Data (EGD)
• Max Server Connections: Up to 16 simultaneous TCP/IP connections
• Expansion: Yes (up to 7 baseplates including remote)
• Battery-Backed Clock: Yes (on-board CR2032)
• Power Draw: 1.8 A @ +5 VDC (higher than 360 due to Ethernet)
• Operating Temp: 0°C to 60°C (32°F to 140°F)
• Storage Temp: -40°C to 85°C (-40°F to 185°F)
• Module Type: Modular (plugs into CPU slot)
• Interrupts: Supported (up to 32)
• Subroutines: Supported (up to 64)
  

  IC693CPU363

The Real-World Problem It Solves

• SCADA-integrated process plants: Water treatment facilities, power plants, and chemical plants where Series 90-30 PLCs connect directly to Ethernet-based SCADA systems via Modbus TCP or SRTP
• Networked HMI systems: Manufacturing floors with multiple panel HMIs connecting over Ethernet to shared PLCs without consuming I/O slots for communication modules
• Multi-PLC EGD systems: Applications requiring cyclic data exchange between multiple Series 90-30 PLCs using Ethernet Global Data for coordinated motion and material tracking

Hardware Architecture & Under-the-Hood Logic

1. Power-up sequence initializes the 80486DX4 core, memory diagnostics, and NVRAM configuration. Simultaneously, the integrated Ethernet controller initializes and attempts DHCP (if configured) or loads static IP address from NVRAM. Battery-backed clock initializes—low battery flags %S0012. Serial ports and backplane drivers come online after Ethernet initialization completes.
2. Integrated Ethernet controller operates through a dedicated TCP/IP stack in the CPU’s microcode. This stack handles IP addressing, TCP/UDP packet assembly, and protocol execution (SRTP, Modbus TCP, EGD) independently of ladder logic execution. The Ethernet portion of the CPU has its own processing resources separate from the main 80486DX4, though they share access to CPU memory (%R) for data exchange.
3. SRTP (Serial Real-Time Protocol over TCP/IP) allows GE Fanuc programming software and HMIs to communicate with the CPU over Ethernet. The CPU acts as both SRTP client and server. As a server, it listens for incoming connections (default port 18245) from programming software for online edits, monitoring, and program transfers. As a client, it can initiate SRTP connections to other GE Fanuc PLCs or HMIs using COMMREQ blocks in ladder logic.
4. Modbus TCP provides standard industrial protocol support. The CPU can function as Modbus TCP Master (client) or Slave (server). As a slave, it responds to Modbus TCP read/write requests from SCADA systems, third-party HMIs, or PLCs. As a master, it initiates Modbus TCP requests to slave devices using ladder logic COMMREQ blocks. Modbus mapping is configured in programming software—map PLC memory (%I, %Q, %R, %AI, %AQ) to Modbus holding/input/ coils and registers.
5. Ethernet Global Data (EGD) enables cyclic data exchange between multiple Series 90-30 PLCs. Configure EGD exchanges in programming software—define PLC memory blocks (%R) to transmit at configured intervals (10-1000 ms). The Ethernet controller handles cyclic transmission independently of the scan cycle. Up to 16 EGD exchanges can be configured per CPU. EGD typically uses UDP for low-latency cyclic communication.
6. RJ-45 port on the CPU faceplate provides standard Ethernet connection (auto-sensing 10/100 Mbps). No external transceiver or AAUI cable required—unlike IC693CMM321 which needs external transceiver. Connect standard Cat5/5e/6 cable directly to the CPU port. LED indicators on the faceplate show link status and network activity. Port auto-negotiates speed and duplex automatically.
7. Maximum 16 simultaneous TCP/IP connections can be maintained. This includes SRTP, Modbus TCP, and any other TCP-based protocols running concurrently. For example, you can have 4 SRTP programming connections, 8 Modbus TCP slaves, and 4 EGD exchanges operating simultaneously. Exceeding 16 connections results in connection rejection or dropped sessions.
8. Backplane communication and expansion rack operation remain identical to standard 360. The CPU scans Rack 0 through Rack 7, gathering I/O images from each rack. Ethernet operations occur asynchronously—the Ethernet controller accesses memory independently, though both compete for memory bandwidth. Heavy network traffic can slightly increase scan time due to memory bus contention, but the dedicated Ethernet controller minimizes impact.
9. Serial ports (Port 1 and Port 2) operate independently of Ethernet. Both support SNP/X master/slave up to 115.2 Kbaud. You can run serial communication simultaneously with Ethernet—no conflicts. Serial communication uses the same COMMREQ architecture as Ethernet master connections. Port 1 and Port 2 are unaffected by Ethernet operations—they remain available for legacy devices or backup communication paths.
10. Power consumption is 1.8 A at +5 VDC—higher than standard 360 (1.6A) due to integrated Ethernet controller. The Ethernet interface draws additional current, especially during high network traffic. IC693PWR330 (5A @ +5VDC) is recommended for most 363 applications. Calculate total current: CPU (1.8A) + all module currents. The higher power draw becomes critical in high-temperature environments—derate the power supply appropriately.

    

    IC693CPU363

Field Service Pitfalls: What Rookies Get Wrong

• Field Rule: The Ethernet port requires initial configuration before communication works. Use VersaPro or Proficy to configure IP address, subnet mask, gateway, and DNS settings. Static IP addressing is strongly recommended—DHCP support is limited and unreliable in industrial environments. Verify IP uniqueness on the network before deployment. Set static IPs outside the DHCP range to avoid conflicts. Configure the port before relying on it for production.

• Field Rule: Modbus TCP requires explicit configuration. In programming software, map PLC memory to Modbus addresses:
  • Modbus Coils (0x) map to %I and %Q
  • Modbus Discrete Inputs (1x) map to %I
  • Modbus Holding Registers (4x) map to %R and %AQ
  • Modbus Input Registers (3x) map to %AI and %RVerify mapping after configuration. Modbus tools can test connectivity before SCADA integration. Don’t assume automatic mapping—configure it explicitly and test with a Modbus client utility.

• Field Rule: Maximum 16 simultaneous TCP/IP connections. Count everything: SRTP programming connections, Modbus TCP masters, Modbus TCP slaves, EGD exchanges, HMI connections. If you need more, install a second Ethernet module (IC693CMM321) in an I/O slot—this provides additional connections up to 16 more. Monitor active connections in programming software. Plan connection allocation during system design—don’t discover the limit during commissioning.

• Field Rule: Keep Ethernet cables separate from power. Minimum 6 inches separation, preferably in separate conduit. Use shielded Cat5e/6 cable with properly grounded foil shield. Industrial Ethernet cable (IP67-rated connectors) is recommended for harsh environments. If you must cross power, do it at 90 degrees. Network performance in industrial environments demands proper cable management—don’t treat Ethernet like office networking.

• Field Rule: The 363’s Ethernet is integrated—no external module required. Use all 10 I/O slots (including Slot 1) for actual I/O. The Ethernet port is on the CPU faceplate itself. Don’t reserve slots for communication modules unless you need additional protocols (Profibus, DeviceNet) beyond TCP/IP. The RJ-45 is right there on the front—use it.

• Field Rule: EGD exchange interval must match application timing requirements. Fast cyclic exchanges (10-50 ms) are needed for motion coordination; slower exchanges (500-1000 ms) work for general data sharing. Configure identical exchange intervals on both sides of the EGD connection. Mismatched timing causes data synchronization errors. Test EGD communication with known data values before trusting it in production. Monitor EGD statistics for lost packets or excessive retries.

• Field Rule: Do the math before powering up. IC693CPU363 = 1.8A @ +5VDC minimum. Add every module’s current draw. For most 363 applications, use IC693PWR330 (5A @ +5VDC) as minimum. The Ethernet controller adds approximately 200 mA over the standard 360 base draw. Never exceed power supply rating—brownouts corrupt NVRAM and force full reload. Calculate carefully, especially in high-temperature environments where power supplies are derated.

• Field Rule: CPU363 has built-in Ethernet—you generally don’t need a separate CMM321 unless you require two physically separate networks (network segmentation) or additional protocol support beyond what the 363 provides. Two Ethernet stacks require independent IP configuration and consume more resources. Plan for segmentation or redundancy explicitly—don’t just throw in a second Ethernet module without a clear purpose. The 363’s built-in port is usually sufficient.

• Field Rule: Ethernet client mode (initiating connections) requires COMMREQ blocks in ladder logic, just like serial master mode. The CPU doesn’t automatically act as a client. Write COMMREQ blocks to open TCP connections, send Modbus TCP requests, and handle responses. Configure COMMREQ parameters: IP address, port number, function code, memory mapping. Test COMMREQ blocks with known target devices before production. Client mode is logic-driven—write the code.

• Field Rule: Check the faceplate LEDs first. LINK LED = green steady when connected to a switch. ACT LED = green flashing when network traffic occurs. If LINK is dark, you have a physical layer problem: bad cable, unplugged port, switch down, or IP conflict. Fix physical layer before diving into software configuration. The LEDs tell you instantly if Ethernet is alive—use them as your first diagnostic step.

• Field Rule: Always back up configuration before making IP changes. If you switch to DHCP, note the assigned IP address immediately (from switch DHCP table or network scanner). If you can’t connect after IP change, connect via serial port (Port 1) to read the current IP configuration. Maintain a serial backup connection whenever making network changes—don’t paint yourself into a corner where Ethernet is your only access and it’s unreachable.

Commercial Availability & Pricing Note