Key Technical Specifications

• Product Model: CXP-544A KOMS-A2
• Manufacturer: KOKUSAI
• Product Type: IGBT Main Control Board / CPU Module
• Operating Voltage: 24VDC Power Supply
• Pulse Frequency Range: 20KHZ to 60KHZ
• Pulse Interval: 180 degrees mutual interval
• PWM Technology: SG3525A pulse formation
• Operating Temperature: -30°C to +65°C
• Environmental Humidity: 20% to 80% (Non-condensing)
• Physical Weight: 0.32 kg
• Communication Support: Datagram and Global Data (GD) communication

 

Product Introduction

When an RF unit in a high-frequency induction heating system starts acting up, the first place I look is the main control board. The KOKUSAI CXP-544A KOMS-A2 is exactly that component. It serves as the brain for the driver, handling everything from control power distribution to generating the precise modulation pulses required to keep the RF unit stable. If this board fails, your process stops.Engineers rely on this specific CPU module because it integrates the SG3525A PWM pulse formation directly into the high-frequency board. It outputs a 20KHZ to 60KHZ frequency range with adjustable dead time, which is critical for preventing IGBT shoot-through. I’ve seen this board handle harsh factory environments for years, though it is notoriously sensitive to power spikes if your 24VDC supply isn’t properly filtered. Treat it right, and it will keep your heating process consistent.

Quality SOP & Tech Pitfalls

The Lab Report:
We don’t just ship these out of a dusty bin. Every CXP-544A KOMS-A2 goes through a strict validation process. First, we do a visual and counterfeit check under magnification to ensure no solder joints are cracked. Next, it goes on a live test rack where we verify the 24VDC draw and measure the PWM output frequency to confirm it hits that 20KHZ–60KHZ spec. We use a Fluke 115 multimeter to check for insulation resistance and ensure there are no internal shorts. Finally, we log the firmware version, seal it in anti-static packaging, and pack it with bubble wrap.The Engineer’s Warning:
Here is where people mess up: dead time adjustment. The dead time on this board is adjustable, but if you tweak it without an oscilloscope, you will fry the IGBTs. I once watched a tech try to “calibrate” a replacement board with a screwdriver while it was powered on. He bypassed the protection logic and blew three expensive transistors in seconds. Always photograph the original board’s jumper settings before pulling it. ESD is another silent killer here; if you don’t wear a grounding strap, you might install a board that works for two days before failing mysteriously.

 

Installation & Configuration Guide

1. Pre-Installation: ⚠️ SAFETY FIRST. Lock out and tag out the main power. Wait at least 5 minutes for the internal capacitors to fully discharge. Take high-resolution photos of the existing wiring and DIP switch/jumper configurations before touching anything.
2. Removal: Label every wire with masking tape. Gently release the DIN clips or mounting screws. Do not yank the board; wiggle it straight out to avoid bending the backplane pins.
3. Installation: Copy the DIP/jumper settings exactly from your photos. This step prevents 90% of startup failures. Align the CXP-544A KOMS-A2 carefully and press it firmly into the connectors. Re-attach the mounting hardware securely.
4. Power-On & Testing: Double-check all wiring against your photos. Restore the 24VDC control power first. Watch the LED boot sequence. If the status lights don’t match the manual, kill the power immediately. Once stable, download your control logic and verify the pulse outputs with an oscilloscope before applying full load.

Compatible Replacement Models

• ✅ Drop-in Replacement: KOKUSAI KOMS-A2 CXP-544A (Reversed part number). This is the exact same board, just listed differently by some suppliers. 100% hardware and software match.
• ⚠️ Software Compatible: KOKUSAI CXP-544A (Without KOMS-A2 suffix). Same core hardware, but verify if your specific RF unit requires the KOMS-A2 firmware patch. May require 1-2 hours of parameter reconfiguration.
• ❌ Hardware Mod Required: KOKUSAI CXP-544A KOMS-A1. Older revision. Requires rewiring and potential backplane modifications. Do not use unless performing a full system overhaul.

 

Frequently Asked Questions (FAQ)

Can I hot-swap this board while the RF unit is running?
Absolutely not. This is a 24VDC control board, not a USB drive. Hot-swapping it will cause a massive voltage spike that will destroy the SG3525A PWM chip and likely take out the IGBTs. Always power down.The board arrived, but the RF unit is throwing a protection fault. Is the board bad?
Maybe, but check your wiring first. I’ve seen this fault triggered simply because a ground wire was left loose during the swap. Verify your 24VDC supply is clean and within spec before RMA’ing the board.Does this board support Global Data (GD) communication?
Yes. The CXP-544A KOMS-A2 supports both datagram and Global Data (GD) communication, which makes integrating it into a larger PLC network much easier without needing extra gateway modules.How do I adjust the dead time safely?
You need an oscilloscope. Connect it to the pulse output, power up the board with no load, and adjust the dead time trimmer until you see the exact microsecond gap specified in your OEM manual. Guessing will destroy your drive.Is this board compatible with older KOKUSAI RF generators?
Generally, yes, but you must verify the physical connector pinout. KOKUSAI updated some edge connectors in the late 90s. Send us a picture of your old board’s connector, and we will confirm compatibility before you buy.What happens if the operating temperature exceeds 65°C?
The board has built-in thermal protection and will likely shut down the RF unit to prevent catastrophic failure. However, running it at the upper limit constantly degrades the electrolytic capacitors. If your cabinet runs that hot, you need to fix your cooling, not just replace the board.