Microprocessor controller for three-step motorized valves, 48×96 / 96×96 (1/8DIN – 1/4DIN) size.
Manufactured using SM Technology, the instrument provides a complete operator interface, protected by a Lexan membrane that ensures level IP65 faceplate protection.
It has 4 keys, two green LED displays, each with 4 digits, 4 red indicating LED's for the 4 logic or relay outputs, and a further 3 LED's that are programmable to indicate the various operational states of the instrument. 10 led red bargraph indication can be associated with analogue outputs for control, inputs, deviations or valve position.
The main input for the process variable is universal and provides the possibility to connect many types of input sensor: thermocouple, resistance thermometer, thermistor, linear inputs, potentiometer, all with the possibility of custom linearisation that can be defined using the faceplate keys.
The type of input is selected from the faceplate keys and no external shunts or adapter are required.
It is possible to activate correction of the input using a linear function defined by way of two points on it.
A second auxiliary isolated analogue input is available, which can also be configured for a linear input or, potentiometer for valve position feedback.
It is possible to configure the 2 available isolated digital inputs for selection of up to 4 local setpoints; start, stop and reset of internal timer; Auto/Man, Loc/Rem functions; alarms memory reset; input hold function.
This instrument has up to 4 relè (3A, 250V) or logic (12Vdc, 20mA) outputs, 2 of which will be dedicated to the open/close valve functions and up to 2 isolated analogic outputs, in voltage or current.
Every output function is configurable from keypad; available functions are control output (open/close valve); alarm output; timer controlled output; digital input repetition; retransmission of process value, setpoint, deviation, alarm setpoint or value read from digital communication.
A further isolated output (10 or 24Vdc, 30mA max.) is available for powering external transmitters or potentiometers.
The serial communication interface RS485 (RS232C compatible) makes it possible to read or modify any parameter and to govern the instrument online (local/remote manual/automatic commutation, internal timer control, direct control of outputs).
Protocols available: MODBUS RTU and CENCAL (Gefran).
Using these protocols it is possible to write to any of the instrument parameters.
Specific parameters are present for the valves control, i.e. the actuator stroke time, the minimum pulse time, the impulsive intervent treshold, the dead zone; also the control type is configurable with or without potentiometer feedback; with PD or PID algorithm.
All the programming procedures of the instrument are facilitated by the grouping of the parameters in function blocks (CFG for the control parameters, Inp for the inputs, Out for the outputs, etc) and by the possibility of selecting a simplified menu for entering the most frequently used parameters.
The instrument can also select the parameters to display depending on the hardware configuration, automatically hiding those that are not influential.
To simplify the configuration even further, a programming kit is available for PC, which includes a menu driven configuration program for Windows and the necessary cable to connect the instrument (see data sheet cod. 80021).