Series-SCD-8

Supported Applications

The Dwyer Series SCD-8 is a multi-loop DIN rail mount temperature controller designed to manage up to eight independent PID control circuits. The series supports applications requiring simultaneous monitoring and regulation of multiple thermal zones, utilizing either thermocouple or resistance temperature detector (RTD) inputs. Each loop can be configured for dual-loop control or combined with alarm functions.

System expansion is supported via SCD-2000 slave modules to accommodate requirements exceeding eight loops without additional power wiring. Configuration and monitoring are handled through standard RS-485 serial communications using Modbus ASCII/RTU protocols, or optionally via a plug-in LED display module for local setup.

Operating Conditions & Performance

The Series SCD-8 operates within an ambient temperature range of 32 to 122°F (0 to 50°C). The unit is designed as an open-type device and requires installation in a protective enclosure. Power requirements are met via a DC 24V isolated switching power supply, with voltage tolerance rated at 90% to 110% of the rated input.

Measurement capabilities vary by sensor type selected for the base unit or expansion cards:

• Thermocouple Inputs (SCD-8000/SCD-4T): Supports types K, J, T, E, N, R, S, B, L, U, and TXK. Measurement ranges span from -200 to 1300°C for Type K down to 100 to 1800°C for Type B.
• RTD Inputs (SCD-8100/SCD-3R): Supports Pt100, JPt100, and Cu50 sensors. Ranges include -200 to 600°C for Pt100 and -50 to 150°C for Cu50.
• Sampling Cycle: The system samples inputs at a rate of 1.0 second per channel across all input types.

The controller features PID, programmable PID, manual, and ON/OFF control methods. Shock resistance is rated at Max. 300m/s² (3 axes, 6 directions), with vibration resistance specified as 10 to 55Hz, 10m/s².

Configuration Options

The Series SCD-8 offers a modular architecture allowing configuration of input channels and output types via accessory cards. The base unit is available in two primary configurations: the SCD-8000 with thermocouple inputs or the SCD-8100 with RTD inputs.

Input Expansion

Additional input capacity can be added using expansion modules, provided they match the sensor type of the base unit:

• SCD-4T: Adds 4 channels of thermocouple input (K, J, T, E, N, R, S, B, L, U, TXK).
• SCD-3R: Adds 3 RTD inputs.

Output Modules

Each control loop supports two outputs. One output must be a relay or pulsed voltage type; the second can be configured for various signal types depending on the installed card (SCD-42, SCD-43, SCD-45, or SCD-46):

• Relay Output: SPST contact rated at Max. AC 250V load, 3A resistive.
• Voltage Pulse Output: DC 24V with a max current output of 40mA.
• Current Output (SCD-45): DC 4 to 20mA; requires resistive load < 500Ω. Available for OUT1 and OUT2 only.
• Analog Voltage Output (SCD-46): 0 to 10VDC; requires resistive load > 1,000Ω. Available for OUT1 and OUT2 only.

Communication & Display Options

The series supports RS-485 communication with baud rates from 2,400bps to 115,200bps. An optional SCD-LED module provides a single-row 7-segment display for viewing present value (PV) and set value (SV), as well as local parameter setup.

Key Product Differences

The Series SCD-8 is distinguished by its input sensor family. The SCD-8000 base unit is configured for thermocouple inputs, while the SCD-8100 base unit is configured for RTD (platinum resistance) inputs.

Output functionality varies by installed accessory card. The SCD-42 provides voltage pulse outputs; the SCD-43 provides relay outputs; the SCD-45 delivers 4 to 20mA current signals; and the SCD-46 supplies 0 to 10V analog voltage. Input expansion is restricted by sensor type: thermocouple base units require SCD-4T modules, while RTD base units require SCD-3R modules.

Physical dimensions for the unit are approximately 96 mm (width) x 96 mm (height) x 100 mm (depth), with a DIN rail clip mounting style. The series includes approvals such as CE, cUL, and UL listing.