DNC Electronics explains the key distinction: "This board is an extended PLC ladder (programmable machine controller) which is loaded up onto the board containing many more EPROMs than the cheaper PMC-L on the memory card can offer."
In FANUC's Series 0-C CNC architecture, PMC (Programmable Machine Controller) ladder programmes come in two tiers:
PMC-L (PMC Light): A compact ladder programme stored on the standard CNC memory card. Limited in programme step count — suitable for machines with relatively simple sequence logic.
PMC-M (PMC Medium): An extended ladder programme stored on the dedicated A16B-1211-0901 ROM board — physically more EPROM capacity than the memory card approach. DNC confirms: "These boards are normally fitted on more complicated 0-C, 0-D, 0-F machine tool installations, allowing 0-C PMC-M ROM PLC ladder functions beyond PMC-L standard."
The implication is straightforward: the A16B-1211-0901 serves the more complex machines — those with larger operator panels, more machine I/O points, more tool change sequences, more auxiliary machine functions — where the PMC-L's step count is insufficient.
| Parameter | Value |
|---|---|
| PMC Type | PMC-M (Medium) |
| Memory Type | ROM (EPROM-based) |
| Compatible | 0-B, 0-C, 0-D, 0-F |
| Machine Types | 0-MC, 0-MD, 0-MF, 0-TC, 0-TTC, 0-TD, 0-TF |
| Format | Half or full width PCB |
| Weight | 0.24 lbs |
| Type | Non-surface-mount PCB |
Fanuc-controller.com confirms for the adjacent A16B-1211-0910 (PMC-M RAM board): "Provides extended RAM memory for PMC ladder logic execution, machine sequence control, and MMC communication functions. Plug-in module mounts on the main control unit, often paired with ROM board A16B-1211-0901 or similar."
In the PMC-M architecture:
PMC-M ROM board fault: A Series 0-C machining centre develops PMC alarms — sequence logic fails, machine functions become unresponsive. The A16B-1211-0901 ROM board is identified as the fault. Replacement (with correct ladder programme content) restores PMC function.
Series 0-C machine tool upgrade from PMC-L: A Series 0-C CNC running PMC-L requires more ladder programme capacity after machine modifications add new sequences. The A16B-1211-0901 PMC-M ROM board is installed to provide the extended EPROM capacity for the larger programme.
Q1: What is the PMC-M ROM board's role when the EPROM content is blank?
The A16B-1211-0901 is a hardware board — its EPROM chips store the actual PMC ladder programme for the specific machine tool. A replacement board with blank EPROMs cannot execute any sequence logic until the correct ladder programme is loaded. The machine tool builder or FANUC service engineer holds the original programme content — confirm this before ordering a replacement board without pre-loaded programme content.
Q2: Is A16B-1211-0901 compatible with both half-width and full-width CNC chassis formats?
CNC Electronics confirms: "Can be plugged into 16 or 32 bit 0-C masters half or full width format." The board physically supports both chassis configurations. Confirm the specific chassis format from the machine tool's panel documentation.
Q3: How does A16B-1211-0901 differ from the PMC-M RAM board (A16B-1211-0910)?
A16B-1211-0901 is the ROM board — non-volatile EPROM-based storage for the PMC ladder programme code. A16B-1211-0910 is the RAM board — volatile working memory for PMC execution. Both are needed for the complete PMC-M system. The ROM board stores the programme permanently; the RAM board provides the execution workspace.
Q4: Does replacing A16B-1211-0901 affect CNC axis parameters?
No. CNC axis parameters (servo gains, feedrate limits, coordinate offsets) reside in the CNC's main SRAM — separate from the PMC ROM board. Replacing A16B-1211-0901 does not affect stored axis parameters. Only the PMC ladder programme is affected — which must be present on the replacement board's EPROM.
Q5: What service options are available for A16B-1211-0901?
Multiple suppliers service this board: MRO Electric (exchange and repair), CNC Electronics (exchange, surplus, and repair), 4D Controls (repair service). This board has comprehensive after-market support across three continents.
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