The Woodward 8200-226 Servo Position Controller (SPC) is a high-performance electronic control device designed for precise positioning of hydraulic or pneumatic actuators. It is the latest released model in the SPC series, directly replacing the previous 8200-224 and 8200-225 models. This controller is widely used in gas turbines, steam turbines, internal combustion engines, and other industrial drive systems to drive single-coil actuators, supporting single or dual redundant position feedback devices.
The 8200-226 offers exceptional flexibility and reliability, accepting position demand signals via DeviceNet or 4-20 mA analog inputs, and driving the actuator through an internal PID control algorithm to achieve high-precision closed-loop position control. Users can easily configure, calibrate, debug, and troubleshoot the controller using the PC-based SPC Service Tool software.
The product is certified for CE, ATEX, CSA, and major marine classification societies (ABS, DNV, LR), making it suitable for Class I, Division 2 and Zone 2 hazardous locations, as well as marine applications. Its wide operating temperature range (-40°C to +70°C) allows it to withstand harsh industrial environments.
Key Features & Benefits
Multiple Control Modes: Supports Proportional, P, PI, PI with Lag, and PI with Lead-Lag control structures, suitable for both proportional and integrating actuators.
Redundant Demand & Feedback: Can be configured with DeviceNet and 4-20 mA as primary/backup demand sources; supports single or dual LVDT/RVDT/DC position sensors for feedback redundancy.
High Accuracy & Stability: System accuracy up to 0.25% of full scale, with configurable error alarm and shutdown thresholds, plus deadband and integrator wind-up protection.
Comprehensive Self-Diagnostics: Includes driver open/short detection, driver current error detection, feedback open-wire detection, excitation voltage monitoring, power supply monitoring, watchdog timer, and more.
Flexible Communication Interfaces: Standard DeviceNet (ODVA conformant), RS-232 service port for PC connection, 4-20 mA demand input, and 4-20 mA position monitor output.
Remote Calibration & Manual Control: Supports remote calibration via DeviceNet, as well as guided local calibration via the service tool; manual stroking mode for commissioning.
Safety & Compliance: Meets North American Class I Division 2 and European Zone 2 hazardous location requirements; complies with ABS, DNV, LR marine rules; features independent external shutdown input and alarm/shutdown relay outputs.
Controller Types & Applicable Actuators
Controller Type | Actuator Type | Description |
Proportional | Proportional (current→position) | Uses command trim integrator to eliminate steady-state error; can disable feedback for open-loop operation |
P Controller | Integrating (current→velocity) | Simplest, very robust, but steady-state error exists if null current not set correctly |
PI Controller | Integrating (current→velocity) | Used in >90% of applications; forces feedback to match demand in steady state |
PI with Lag | Integrating (current→velocity) | Adds lag filter on demand to reduce overshoot; use for critical processes |
PI with Lead-Lag | Integrating (current→velocity) | Adjusts apparent bandwidth of actuator; can increase or decrease response |
Installation & Wiring Highlights
Power & Grounding
Power line must be protected with a 5 A fuse.
The SPC chassis must be connected to Protective Earth (PE) using the ground lug; use same wire gauge as input power.
For best noise immunity, route power cables separately from low-level I/O cables.
Shields & Grounding
Use shielded twisted-pair wiring for all signals.
Terminate shield only at the SPC end (single-point grounding) to avoid ground loops.
Recommended strip length: 8 mm (0.3 inches). Do not tin (solder) the wire ends – spring terminals rely on bare stranded wire.
Hazardous Location Requirements (Zone 2 / Class I Div 2)
Must be mounted in an enclosure with IP54 or higher ingress protection.
Do not remove covers or connect/disconnect connectors while power is on unless area is known to be non-hazardous.
Substitution of components may impair suitability for hazardous locations.
External Shutdown & Reset
Shutdown Input: Normally closed (contacts closed) for normal operation; opening the contacts disables actuator driver output.
Reset Input: Normally open; momentary closure resets latched alarms/shutdowns.
Status Relay Driver Output Wiring
Alarm and shutdown outputs are unpowered (dry contacts). An external power supply (max 32 Vdc / 500 mA) must be connected in series with the output and load.
Relay driver is energized during normal operation and de-energized during alarm/shutdown condition.
Configuration & Calibration
The SPC is configured and calibrated using the SPC Service Tool software, which runs on a Windows PC and communicates via RS-232 serial port. For modern computers without a serial port, Woodward offers a USB-to-serial adapter kit (P/N 8928-463).
Configuration Steps
Create a new configuration or open an existing one (.cfg file).
Select the correct Service Interface Version (match SPC software part number).
Configure the following tabs in the Configuration Editor:
Servo Controller: Controller type, gains, null current, current limits, wind-up thresholds.
Position Demand: Source (DeviceNet only/primary, Analog only/primary), scaling, fault response.
Feedback: Feedback device type (4-20mA, LVDT/RVDT, DC voltage), excitation, range thresholds.
Position Error: Two independent error thresholds/delays, latching behavior.
Driver: Current range, dither, fault delay, fault response.
DeviceNet: Baud rate, MAC ID, remote calibration enable.
Save the configuration file.
Load the configuration to the SPC (loading causes the SPC to shut down).
Run the Calibration Assistant:
Step 1: Introduction
Step 2: Set minimum position (0%)
Step 3: Set maximum position (100%)
Step 4: Verify calibration (step response test)
Step 5: Save calibration settings
Switch SPC to Run mode.
Calibration Methods
Service Tool Calibration: Guided wizard where user manually strokes actuator to endpoints and records feedback signals.
DeviceNet Remote Calibration: Performed by a host control system over DeviceNet (requires checking "Calibration will be performed through DeviceNet" in the Service Tool).
Diagnostics & Protection Features
The SPC provides extensive diagnostic and protection functions. Key faults are summarized below:
Fault Name | Type (Configurable) | Description |
Driver Current Fault | Alarm / Shutdown | Actual current does not match demanded current within ±20% of full scale |
Driver Overcurrent Fault | Shutdown (fixed) | Measured current exceeds demanded by >25% of full scale |
Driver Open Fault | Alarm / Shutdown | Open actuator coil detected (threshold ≈ 13 / max required current) |
Driver Short Fault | Alarm / Shutdown | Shorted actuator coil detected (threshold ≈ 1 / full scale current) |
Feedback 1/2 Open Fault | Alarm | Open wire in feedback transducer circuit (only for isolated outputs) |
Feedback 1/2 Range Fault | Alarm | Feedback voltage exceeds calibrated range ± threshold |
Position Error Fault 1/2 | Alarm / Shutdown | Difference between demand and feedback exceeds threshold for delay time |
Excitation Fault | Alarm | Excitation voltage not within ±0.2 Vrms of configured value |
DeviceNet Communication Fault | Alarm / Status | No master, slow data, MAC ID conflict, CAN bus problem, master idle |
External Shutdown Input | Shutdown (fixed) | Shutdown input contacts open |
Internal Fault | Shutdown (fixed) | Memory test, supply voltage, A/D reference, CPU power monitor, watchdog |
All alarms and shutdowns can be configured as latching or non-latching, and can be reset via the reset input or the Service Tool.
Compliance & Certifications
Certification | Standard / Body | Applicable Region / Condition |
CE (EMC) | 89/336/EEC | Electromagnetic compatibility |
CE (ATEX) | 94/9/EEC | Equipment for potentially explosive atmospheres (Zone 2, Group IIC) |
CSA (North America) | Class I, Division 2, Groups A, B, C, D, T4 @ 70°C | Hazardous locations in Canada and US (component certification) |
Marine | ABS, DNV, LR (ENV1, ENV2, ENV3) | Ships, high-speed craft, and mobile offshore units (models 8200-225 & 8200-226 only) |
DRFD to SPC Replacement Cross-Reference
The SPC 8200-226 can replace many older DRFD (Digital Remote Final Driver) models. A sample cross-reference is shown below (see manual Appendix A for full list):
Old DRFD Model | Channels | Power | Latch | Driver Ranges (mA) | SPC Replacement Notes |
0051 | Redundant | AC | Latch | ±20,40,125,250 | No direct replacement; SPC needs external power redundancy; no 125mA range |
0062 | Redundant | AC | Latch | ±20,40,125,250 | Requires two SPCs for redundancy |
0072 | Single | DC | Latch | ±10,20,100,250 | Two SPCs may need retuning |
0081 | Single | DC | Latch | ±10,20,100,250 | One SPC works; may need retuning |
0302 | Redundant | DC | Latch | ±10,20,100,250 | Two SPCs + external power redundancy |
0412 | Single | AC | Latch | ±20,40,125,250 (PI) | Two SPCs; no 125mA range |
0632 | Single | DC | Latch | ±10,20,100,250 (EHPC) | External power needed for EHPC transducer; may need retuning |
Important differences between DRFD and SPC:
SPC enclosure is not NEMA 4 rated.
SPC input power is 18-32 Vdc (DRFD uses 120 Vdc/Vac).
SPC status contacts are normally closed (NC) and rated 18-32 Vdc only.
SPC maximum output current is 250 mA.
Service & Technical Support
Woodward offers several service options to maximize equipment uptime:
Replacement/Exchange (24-hour service): Provides a like-new replacement unit quickly (usually within 24 hours). Flat rate plus core charge; core return credit within 60 days.
Flat Rate Repair: Fixed-cost repair for most standard products; includes warranty on replaced parts and labor.
Flat Rate Remanufacture (mechanical products only): Unit returned to like-new condition with full product warranty.
