When working with industrial control devices like the Yamatake SDC20, always follow the safety precautions outlined in the user manual to avoid injury or damage to the equipment.
Yamatake (Azbil) SDC20 is a compact, digital indicating controller designed for precise PID control of temperature and other industrial variables. While it is a legacy model, it remains widely used in various manufacturing environments for its reliability and straightforward interface. Core Functionality is a single-loop controller that utilizes PID control with "RationaLOOP"
—an Azbil proprietary algorithm designed to improve control performance by minimizing overshoot and providing better disturbance rejection compared to standard PID. Key Technical Specifications Input Types:
Multi-range capability supporting thermocouples (K, J, T, E, R, S, B, N, PL II, WRe5-26), RTDs (Pt100), and DC voltage/current (4-20mA, 0-5V, etc.). Control Outputs:
Available in several variations including relay, voltage pulse (for SSR drive), and current (4-20mA).
Dual 4-digit LED display. The upper display (green) typically shows the Process Value (PV) , while the lower display (orange) shows the Setpoint (SP) Standard 1/8 DIN size ( Navigation and Programming The controller interface consists of four primary keys:
Used to switch between operating modes and to confirm setting changes. Para (Parameter) Key: yamatake sdc20 user manual
Cycles through the parameter settings within a specific group. Up/Down Arrows: Used to increase or decrease values during configuration. Operation Modes
The manual categorizes settings into different "Banks" or setup groups: Operation Bank:
Daily adjustments like Setpoint (SP) and Auto-tuning (AT) initiation. Control Bank:
Tuning parameters including Proportional Band (P), Integral Time (I), and Derivative Time (D). Setup Bank:
Deep-level configuration such as input type selection, range limits, and output scaling. Quick Setup Steps
Ensure power is connected to the correct terminals (typically 1 and 2 for AC power) and that the sensor input matches the terminal diagram on the side of the unit. Input Configuration: When working with industrial control devices like the
Enter the Setup Bank to define the sensor type. If the input type does not match the physical sensor, the unit will display an "AL01" (Sensor Error). Auto-Tuning (AT):
To automatically calculate PID values, navigate to the AT parameter in the Operation Bank and set it to "1" (ON). The controller will oscillate the output to learn the thermal characteristics of the system. Common Error Codes PV input failure (sensor burnout or incorrect wiring).
Configuration data error (usually requires a factory reset or hardware check). Internal memory error.
Since Yamatake rebranded to Azbil in 2008, searching for the manual requires using both names. Here are the safest sources:
Warning: Avoid "free manual" websites that require credit card info. The SDC20 manual is legally available for free as a legacy support document.
The SDC20 interface looks simple (an 8-segment LED display and 4 buttons), but it is modal. Since Yamatake rebranded to Azbil in 2008, searching
For the SDC20 to control a process without oscillation, you must run auto-tuning. The manual describes two types:
How to start AT (from manual):
Warning: Do not start AT if the process is already stable near setpoint. The manual recommends starting AT at least 50% below setpoint.
7. Maintenance and Troubleshooting
The Yamatake SDC20 is a compact, programmable temperature controller often used in HVAC, industrial ovens, food processing, and other applications requiring reliable temperature regulation. This blog post summarizes the key features of the SDC20, how to set it up, practical usage tips, troubleshooting pointers, and safety/maintenance advice to help you get the most from the device.