DIN-rail-mounted, high-density modular system has a sample cycle time of 250 ms, providing accuracy of 0.2 percent. The control method of Model SRZ is selectable between position proportional control and cascade control in addition to the typical heat only and heat/cool methods. The Brilliant PID II algorithm with enhanced tuning achieves a quick rise/drop to setpoint and with greater protection from overshoot/undershoot cause by external disturbances. True universal input includes 10 thermocouples types, RTD, voltage or current. A single module may provide up to four channels of heat-only or two heat/cool, of which up to 16 modules may be connected.