EZ-ZONE® ST Controller

A Scalable Modular PID Controller

The Ez-Zone® ST is a complete thermal system controller in a compact touch safe modular package that can be either DIN rail or back panel mounted.  The modular base measures less than 4” wide and is just under 8” long (vertical) and less than 1-1/4” deep.  Standard features are a micro-processor based PID controller utilizing Watlow’s Tru-Tune®+ adaptive control and serial communications for fast and easy configuration and set-up via a PC or laptop using free software provided by Watlow®.  An internal built-in SSR driver is included for controlling a user selected load switching SSR up-to 90A.  Optional components such as a relay heat sink, over/under controller, and an electro-mechanical contactor with power supply for power safety shutdown can also share the same modular base and only add an additional 5” to the depth of the complete package.


The Ez-Zone®ST has program selectable universal input for:

  • Thermocouple either grounded or ungrounded
  • RTD sensor either two or three wire
  • Process signal either 0~20mA or 0~10vDC
  • Potentionmeter
  • Scalable
  • Inverse scaling


Watlow EZ-ZONE ST image

Ez-Zone®ST user options

  • Load switching zero cross solid state relay
  • Load switching phase angle solid state relay
  • Heat sink for solid state relay
  • Safety shutdown definite purpose electro-mechanical relay
  • Over/Under controller
  • Burned out heater or failed SSR current monitoring
  • Remote user interface with network capability Ez-Zone®EZKB


Watlow EZ-ZONE ST image

Ez-Zone®ST Control Features

  • User selectabe: Heat/Cool, On/Off, P, PI,PD,PID or Alarm action
  • Auto Tune with Tru-Tune®+ adaptive control algorithm
  • Control sampling rates: input= 10-Hz, outputs= 10-Hz
  • Four Ramp/Soak profiles with 40 total steps
  • Real time clock and Battery backup
  • Retransmit input signal for remote recording


The Ez-Zone®ST controllers are programmed by menu driven choices that help simplify operator control.  The controller has a 200kA short circuit rating tested up to 480vAC when used with required fusing.  The compact touch safe design complies with IP2X and has agency approvals from UL® CSA, CE, RoHS, and W.E.E.E. all with a three year warranty.