RKC CB900 Modules: CB900 FD10-8*GB-NN/A/Y

Technical Dossier

Product Details And Specifications

RKC CB900 Series: Comprehensive Module Range and Technical Overview

The RKC CB900 series is a high-performance digital temperature controller manufactured by RKC Instrument Inc. (Japan), widely deployed across global heavy industry sectors including petrochemical plants, nuclear facility auxiliary systems, oil refineries, pharmaceutical batch reactors, and steel mill heat treatment lines. Its compact DIN-rail-compatible form factor, combined with multi-input sensor compatibility and dual-loop control capability, has made it a standard-specification component in distributed control system (DCS) architectures throughout Asia, Europe, and the Americas. The CB900 line occupies the mid-to-high tier of RKC's controller portfolio, positioned above the CB100/CB400 entry-level range and below the SR-Mini modular system, making it the preferred choice for applications requiring precision ±0.1°C accuracy with PID auto-tuning in a standalone package.

The Evolution of CB900 Architecture

The CB900 platform was introduced by RKC Instrument as a successor to the CB-series controllers of the 1990s, incorporating digital communication interfaces absent from earlier analog-output predecessors. Early CB900 variants supported RS-485 serial communication using RKC's proprietary protocol, enabling integration with SCADA systems of that era. Subsequent hardware revisions introduced support for Modbus RTU, expanding compatibility with third-party PLCs and HMI panels from Siemens, Mitsubishi, and Omron.

The model designation system encodes hardware configuration directly into the part number. In the SKU CB900 FD10-8*GB-NN/A/Y, the suffix breakdown is as follows: FD10 denotes the output type and control action; 8 indicates the number of control outputs or relay configuration; GB specifies the communication option (RS-485 with Modbus); NN represents the alarm output configuration; A denotes the power supply voltage class (100–240 VAC); and Y indicates the terminal/connector type. This alphanumeric encoding system remained consistent across CB900 production runs, allowing engineers to cross-reference legacy documentation against current replacement units.

As of 2024, the CB900 series has entered the mature/end-of-life phase of its product lifecycle. RKC Instrument has transitioned its active development focus to the REX-F and MA900 series platforms. However, the CB900 remains in active service at thousands of installed sites globally, and RKC continues to supply spare units through authorized distributors. For sites where CB900 units are no longer available through standard channels, DriveKNMS maintains a dedicated inventory of new-old-stock (NOS) and reconditioned units to support long-term maintenance contracts.

CB900 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly deployed configurations within the RKC CB900 product family. Units are categorized by primary function:

Temperature Controllers – Standard Output

• CB900 FD10-8*GB-NN/A/Y: Dual PID controller, RS-485 Modbus, 100–240 VAC, screw terminal, 8-relay output configuration.
• CB900 FD08-8*GN-NN/A/Y: Single-loop PID, no communication option, 100–240 VAC, relay output, standard alarm.
• CB900 FK02-8*GN-NN/A/Y: Voltage pulse output for SSR drive, no RS-485, 100–240 VAC, DIN rail mount.
• CB900 FD10-8*GN-NN/A/Y: Dual PID, no communication, 100–240 VAC, relay output, standard terminal.
• CB900 FD10-8*GB-NN/D/Y: Dual PID, RS-485 Modbus, 24 VDC power supply, screw terminal.
• CB900 FD10-8*GN-NN/D/Y: Dual PID, no communication, 24 VDC, relay output, DIN rail.

Temperature Controllers – Analog Output (4–20 mA)

• CB900 FD10-8*GB-AN/A/Y: Dual PID, RS-485, 4–20 mA retransmission output, 100–240 VAC.
• CB900 FK02-8*GB-AN/A/Y: Voltage pulse + 4–20 mA output, RS-485 Modbus, 100–240 VAC.
• CB900 FD08-8*GB-AN/A/Y: Single-loop, 4–20 mA output, RS-485, 100–240 VAC, standard alarm.

Temperature Controllers – Heating/Cooling Control

• CB900 FD10-8*GB-HN/A/Y: Dual PID heating/cooling, RS-485, relay + voltage pulse output, 100–240 VAC.
• CB900 FD10-8*GN-HN/A/Y: Heating/cooling PID, no communication, relay output, 100–240 VAC.
• CB900 FK02-8*GB-HN/A/Y: Heating/cooling, voltage pulse output, RS-485, 100–240 VAC.

Temperature Controllers – Extended Alarm & Special Function

• CB900 FD10-8*GB-NA/A/Y: Dual PID, RS-485, extended 4-alarm output configuration, 100–240 VAC.
• CB900 FD10-8*GB-NN/A/N: Dual PID, RS-485, 100–240 VAC, push-in spring terminal variant.
• CB900 FD10-8*GN-NA/A/Y: Dual PID, no communication, 4-alarm output, 100–240 VAC, screw terminal.
• CB900 FD08-8*GB-NA/A/Y: Single-loop, extended alarm, RS-485, 100–240 VAC.

Sourcing Hard-to-Find & Obsolete CB900 Parts

With the CB900 series in its end-of-life phase, procurement teams at chemical plants and power generation facilities increasingly encounter lead times of 16–52 weeks through standard distribution channels, or outright discontinuation notices for specific suffix configurations. DriveKNMS operates a dedicated obsolete and hard-to-find industrial parts division that maintains physical stock of CB900 units across multiple suffix variants.

Our sourcing protocol for CB900 units includes: direct acquisition from decommissioned plant equipment, partnerships with authorized RKC regional distributors in Japan and Southeast Asia, and a cross-reference database that maps discontinued CB900 configurations to functionally equivalent current-production alternatives. For sites requiring exact form-fit-function replacements — particularly where DCS parameter files are locked to specific CB900 communication addresses — we supply units pre-configured to match the original installation's Modbus node ID and baud rate settings upon request.

DriveKNMS maintains export compliance documentation for CB900 units shipped to regulated industries, including material certificates and country-of-origin declarations (Japan, JIS-compliant manufacturing).

Quality Control for the CB900 Range

Each CB900 unit processed by DriveKNMS undergoes a structured inspection and functional verification protocol prior to dispatch. The CB900's internal architecture — comprising a microprocessor control board, input signal conditioning circuit, output relay or SSR drive stage, and RS-485 communication ASIC — requires targeted testing at each subsystem level.

Our CB900 test procedure includes: (1) Input calibration verification — thermocouple (K, J, T, E, R, S, B, N types) and RTD (Pt100) input accuracy checked against NIST-traceable reference standards to ±0.1°C; (2) Output relay endurance check — relay contact resistance measured before and after 1,000 simulated switching cycles; (3) RS-485 communication integrity test — Modbus RTU read/write register verification at 2400, 4800, 9600, and 19200 baud; (4) Power supply stress test — unit operated at 85% and 110% of rated voltage for 30 minutes each; (5) PID auto-tune simulation — control loop response verified against a calibrated thermal load simulator. Units that fail any stage are quarantined and not offered for sale.