Yamatake SDC35/36 Controller Application Guide

External Digital Input (DI): Up to 4 points, assignable functions include: SP number switch, PID group switch, RUN/READY switch, AUTO/MANUAL switch, LSP/RSP switch, AT start/stop, SP ramp enable, PV value hold, timer start/stop, etc.

Current Transformer Input (CT): 2-point, paired with QN206A (aperture 5.8mm) or QN212A (12mm) current transformers, to detect heater load current (0.4-50A). Can be achieved:

When the control output is turned on: detect heater disconnection or overcurrent.

When the control output is OFF: detect SSR short circuit (still current flowing).

Remote Set Point (RSP): It can achieve external control by inputting set points from PLC or upper computer through 0-20mA/4-20mA or 0-5V/1-5V/0-10V.

Communication interface: RS-485 (Modbus RTU, slave), baud rate 4800-38400, up to 31 units in a network; There is also a dedicated Loader interface (19200 bps) connected to SLP-C35.

2.4 Power Supply and Working Environment

Power supply: 85-264Vac (50/60Hz) or 24Vdc model (selected when ordering), power consumption ≤ 12VA.

Working temperature: 0-50 ℃ (upper limit is 40 ℃ when installed horizontally), humidity 10-90% RH, no condensation.

Insulation withstand voltage: 1500Vac/1min between the power supply end and the secondary end, insulation resistance ≥ 10M Ω (500Vdc).

External dimensions: SDC35 is 48 × 48 × 65mm (panel opening 45 × 45mm), SDC36 is 96 × 96 × 65mm (opening 92 × 92mm).

Key points of installation and wiring engineering

3.1 Panel Opening and Installation

Use a dedicated installation bracket (included with the package). Insert the controller into the opening from the front, cover the bracket from the back, and tighten the screws until there is no gap - excessive tightening may cause deformation of the housing.

When three or more units are installed horizontally side by side, the upper limit of the ambient temperature is reduced to 40 ℃, and attention should be paid to heat dissipation.

3.2 Terminal isolation and grounding

The internal isolation structure of SDC35/36 is as follows (see manual diagram):

The power supply, control output 1/2, CT input, MFB input, relay output, RS-485, RSP input, etc. are isolated from each other (solid line part).

The digital input (DI1-4) is not isolated from the internal circuit (dashed part), and attention should be paid to common mode voltage.

Grounding: The grounding terminal of the power terminal must be reliably connected to the protective earth (PE) to reduce common mode interference.

3.3 Anti noise measures

The controller is sensitive to noise on the power and signal lines, especially when there are contactors, SCR power regulators, high-frequency welding machines, and other equipment on site.

Recommended measures:

Parallel CR filter (Yamatake model 81446365-001, or Matsuo 953M50033311) at the power input end.

The power cord should be as short as possible and laid separately from the signal line (with a spacing of ≥ 50cm), and should not be threaded into the same cable tray or metal tube.

The input signal lines (TC, RTD, 4-20mA) use shielded twisted pair cables, with the shielding layer grounded at one end (controller side).

The CT input line should be twisted and kept away from the power line.

3.4 Precautions for CT wiring

Open circuit is strictly prohibited on the secondary side of CT, otherwise high voltage danger may occur. When the controller is not in use, be sure to short-circuit the CT input or connect it to the controller first.

Measurement range 0.4-50A rms (50/60Hz). The transformation ratio is fixed at 800:1 (such as QN206A rated input 50A, output 62.5mA, but the controller is compatible with 0-50mA). Attention: The internal sampling resistor of the controller is fixed and does not require external connection.

Minimum ON time requirement for detection: For wire breakage detection, the output ON time should be controlled to be ≥ 0.3s; for SSR short circuit detection, the output OFF time should be controlled to be ≥ 0.3s.

Parameter setting and tuning

4.1 Using Smart Loader Package (SLP-C35)

SLP-C35 is a PC software (supporting Windows) that connects to the Loader interface on the front of the controller via a dedicated cable (19200 bps). The functions include:

Parameter Read Write and Backup

Real time trend monitoring (PV, SP, MV)

Automatic Tuning (AT) Wizard

Event configuration, DI allocation

Copying parameters of multiple controllers

First use steps:

Install the software and connect the cable (2m dedicated line).

After power on, the software automatically recognizes the device.

Read the current parameters and save them as a project file.

Modify input type, range, control mode, PID value, etc. as needed.

Write into the controller and perform functional testing.

4.2 PID Auto tuning

SDC35/36 adopts a Limit Cycle to automatically tune PID parameters. Users can choose from three control features:

Standard: Balance response and stability.

Fast disturbance response: responds faster to load changes, but may experience slight overshoot.

Reduce up and down fluctuations: more suitable for objects with high inertia and low overshoot.

Operation:

Stabilize the PV near the working point.

Set AT startup (can be done through DI or parameter AT=1).