Manual

36
CONTROL INSTRUCTIONS
The special features of the Protocol Plus
TM
control include:
• PID tuning
• Ramp/Soak programming of up to 64 segments
• Segment looping and profile linking
• Built-in manual reset high limit control
• Built-in process timer
• Dedicated LED display for process temperature
• Multi-purpose two-line LCD display with backlight
• Auto-tuning
• Security access
• Process temperature retransmission signal
• Digital inputs for remote profile control
• Optional relay outputs for events, alarms, or end-of-cycle signal
• Optional real-time-clock
• Optional RS232/RS422/RS485 MODBUS communications
Theory of Control Operation
The Protocol Plus is a modular microprocessor based digital temperature controller. The
Protocol Plus operates as a dual functioning controller/high limit instrument. The control
portion utilizes a time-proportioning voltage signal to control heating devices with
minimal temperature fluctuations.
The high limit portion protects the product and/or the oven from overheating. If the
product being processed has a critical high temperature limit, the high limit setpoint
should be set to a temperature somewhat below the temperature at which the product
could be damaged. If the product does not have a critical high temperature limit, the
high limit setpoint should be set 5 to 15 degrees higher than the maximum programmed
setpoint at which the oven will operate.