Watlow Series 988 Controller

2. Control mode and algorithm

Control type: supports normal control, cascade control, proportional control, differential control

Algorithm selection: Single group PID, proportional/differential control (with manual reset), dual group PID, duplex (heating/cooling) control can be selected

Self tuning function: supports automatic tuning of PID parameters, which needs to be started in the system menu. During the tuning process, the controller enters switch control mode

3. Alarm and error handling

Alarm function: Output 2-4 can be configured as an alarm, supporting lock type (manual reset required) and non lock type (automatic reset after fault relief)

Error code: including A/D conversion error, sensor over/under range error, ambient temperature error, etc. When an error occurs, the controller automatically switches to manual mode and maintains the preset output

Detailed explanation of software functions

1. General software functions

Core functions: including burst fire, communication function, dead zone control, digital events, heater current monitoring, input filtering, linearization, ramp to set point, remote set point, retransmission function, sliding line feedback, etc

Application scenario: Sudden ignition is suitable for zero crossing solid-state devices; Dead zone control prevents simultaneous activation of heating/cooling outputs; Sliding line feedback can control valve position

2. Enhanced software features (models equipped with enhanced software only)

Cascade control: precise control is achieved through two control loops (outer loop monitoring process values, inner loop monitoring heat source temperature) to reduce overshoot

Dual PID group: supports two independent PID parameters, which can be switched based on process values, setpoints, or event inputs

Proportional control: controlling the proportional value of one process variable to another, suitable for material mixing scenarios

Maintenance and Support

1. Calibration and Diagnosis

Calibration requirements: Factory calibrated. If regular calibration is required, please refer to the dedicated calibration manual

Diagnostic function: The software version, serial number, ambient temperature, A/D count, test display, and output functions can be viewed through the diagnostic menu

2. Warranty and Returns

Warranty period: 36 months warranty (from the date of first purchase and use), covering material and process defects

Return process: Contact customer service first to obtain a Return Merchandise Authorization (RMA) number. For returned products, prepaid shipping fees are required. For unused products, a 20% restocking fee may be charged

3. Technical support

Support time: 7am to 5pm Central Time in the United States

Support preparation: When contacting, please provide the controller model (12 digit number, located on the shell sticker and circuit board), user manual, configuration information, and diagnostic menu readings

Key Appendix Information

1. Specification parameters

Input type: Supports process signals such as J/K/T/N/R/S/B thermocouples, 100 Ω RTDs, 4-20mA, 0-10V, etc

Output options: Solid state relay (0.5A), electromechanical relay (5A), open collector, process output (4-20mA/0-10V), etc

Accuracy: ± 0.1% ± 1 LSD of full scale (ambient temperature 25 ℃± 3 ℃, rated voltage ± 10%)

2. Glossary of Terms

Core terms: including definitions of professional terms such as annunciator, burst fire, cascade control, PID (proportional integral derivative), dead band, etc