Oliver-252RP Sakurai Printing Press Control System with Mitsubishi Melsec PM-120M and F1-20-MR PLCs
Product Overview
The Oliver-252RP is a printing press manufactured by Sakurai (model 52x36). Its control system incorporates Mitsubishi Melsec programmable logic controllers: the PM-120M main sequencer and the F1-20-MR compact PLC. These units work together to manage press speed, paper feed, registration, and safety interlocks. This combination represents a classic example of distributed control in offset printing machinery.
Mitsubishi Melsec PM-120M – Main Control Unit
Model: Melsec PM-120M (programmable sequencer)
Power Supply: 100-240 VAC
Program Memory: 1K steps (RAM with battery backup)
I/O Capacity: 120 points (max.)
Instruction Execution Speed: 5 μs (basic logic)
Communication: Dedicated link to F1-20-MR
Mitsubishi F1-20-MR – Compact Expansion PLC
Model: F1-20-MR
I/O Points: 12 inputs, 8 relay outputs
Power Supply: 24 VDC
Output Rating: 2 A per relay (250 VAC)
Mounting: DIN rail
Control Architecture
In the Sakurai Oliver-252RP press, the PM-120M handles the main logic: motor start/stop, clutch engagement, counter presets, and error handling. The F1-20-MR is typically dedicated to specific sections of the press, such as the feeder or delivery stacker, providing local I/O while communicating with the PM-120M via a serial link or hardwired signals.
Programming and Configuration
Both PLCs are programmed using Mitsubishi’s Medoc software (MS-DOS based) or via a handheld programmer (F2-20P). The PM-120M’s ladder logic includes dedicated instructions for rotary encoder input (for registration) and single-step sequencing for press cycles. The F1-20-MR can operate independently or as a slave, receiving commands from the PM-120M.
Industrial Applications
Original Sakurai Oliver-252RP sheet-fed offset presses
Retrofit control systems for older Sakurai presses
Documentation and spare part replacement for existing machines
Conclusion
The combination of Mitsubishi Melsec PM-120M and F1-20-MR PLCs forms a reliable control backbone for the Sakurai Oliver-252RP printing press. These units provide robust sequential logic, ease of debugging, and proven longevity in high-vibration industrial environments.
