Yamatake SDC35/36 Controller Application Guide

The controller will automatically adjust the output step change, generate oscillations, and record the limit period.

After the tuning is completed, the PID parameters are automatically stored in the current group.

Notes:

When self-tuning, the final control components (heater, SSR, contactor, etc.) must be powered on simultaneously or in advance with the controller, otherwise they cannot respond correctly.

During the tuning process, it is prohibited to switch between RUN/READY or power off.

4.3 Just FITTER Technology

Just FITTER is an overshoot suppression algorithm that dynamically adjusts the output by monitoring the PV rise rate. Users can set the "overshoot suppression coefficient" (0~100), the larger the coefficient, the stronger the suppression. For processes that do not allow overshoot (such as biological cultivation and plastic extrusion), it is recommended to set it to 50-80.

4.4 Multiple sets of PID and SP numbers

The controller can store up to 8 sets of PID parameters and 8 set values (SP numbers). It can be switched online through DI input or communication. Suitable for producing equipment with multiple varieties and different temperature ranges.

Common troubleshooting and maintenance

6.1 PV display abnormality (---- or 9999)

Possible reasons: sensor disconnection, incorrect input type setting, and failure of cold end compensation.

Solution: Check the TC/RTD wiring and measure the resistance or millivolt value with a multimeter. Enter the settings menu to verify the input type (such as K-type Pt100）。 If it is a thermocouple, check the cold end compensation method (internal/external).

6.2 Controller does not output, OUT indicator light does not light up

Possible reasons: READY mode (parameter rEAdY=1), or manual mode with MV=0, or PID parameter causing output to be 0.

Solution: Check the status indicator lights "man" (manual) and "rdy" (ready). Set rEAdY to 0 or switch to AUTO mode.

6.3 Heater disconnection alarm, false alarm or missed alarm

Possible reasons: CT ratio setting error, improper current threshold, insufficient minimum ON/OFF time.

Solution: Use a clamp gauge to measure the heater current and compare it with the displayed value on the controller. Adjust the alarm threshold (it is recommended to set it to 50% of the normal current). Ensure that the control output ON time is ≥ 0.3s (if the cycle time is too short, the cycle can be increased).

6.4 RS-485 communication failure

Possible reasons: duplicate address, inconsistent baud rate, unconfigured terminal resistance, reversed wiring polarity.

Solution: Check station number (1-31), confirm that the baud rate, data bits, and parity bits of the master and slave stations are consistent. Add 120 Ω terminal resistors at both ends of the bus. SDC35/36 uses a three wire system (+, -, SG), do not connect SG to the ground.

6.5 Self tuning does not converge or oscillates violently

Possible reasons: object nonlinearity, large actuator dead zone, insufficient sampling period.

Solution: Manually adjust the PID or reduce the output cycle. For objects with large lag, the integration time can be increased.

Maintenance and lifespan management

Regular calibration: It is recommended to use a standard signal source to check PV accuracy every year, especially for cold end compensation.

Relay lifespan: The electrical lifespan of the control output relay (3A/250Vac) is approximately 50000 cycles. For frequent on-off situations, voltage pulse output+SSR or external solid-state relay should be used.

Spare parts: After long-term shutdown, at least one spare machine of the same model should be retained for quick replacement. When replacing, use SLP-C35 to upload the original parameters and download them to the new machine.

Cleaning: Wipe the panel with a soft cloth and avoid using organic solvents.

Typical application cases

8.1 Injection molding machine barrel temperature control

Configuration: SDC36, K-type thermocouple input, voltage pulse output drives SSR heating. Heating/cooling dual output (the second output is a relay controlled cooling fan).

PID parameters: Self tuning selection of "fast disturbance response" effectively suppresses temperature fluctuations caused by feeding.

Event: PV high limit alarm (to prevent overheating of the material cylinder), Loop Diagnosis 2 detects heater disconnection.

8.2 Constant temperature and humidity chamber (environmental test)

Configuration: SDC35, Pt100 input, 0-10V output to drive the power regulator for heating, and another 4-20mA output to drive the humidifier.

Multiple sets of PID: one set each for the low temperature section and high temperature section.

RSP input: PLC provides program curve (via 4-20mA), and the controller locally executes PID.

8.3 Food sterilization kettle

Configuration: SDC36, dual input for temperature and pressure (via linear input 4-20mA transmitter). The control output is a relay driven steam valve.

Event: Deviation alarm, SP slope status indication.