Multiloop controller handles up to 16 channels

Author : M Babb

05 September 2009

GF_LOOPER is an advanced series of multi-runner controllers offered in 8 to 16 zone configurations, with complete and easy to use functions for a variety of applications. The operator interface is based on an LCD TFT colour touch screen, 3.5 and 5.7 inch, designed for very easy use.


The work and configuration pages are identified by keys with intuitive icons that give immediate access to selected functions.

Predefined password levels, compatible with operator authorisation, guarantee controlled access to functions.

The supervision pages offer a complete view of the zones, each with its own PV, SP, output power, and main alarms status levels.

All of the control zones can be switched on or off with a single button, and all of the setpoints can be simultaneously changed by the same engineering quantity with two up/down keys.
Selecting the page of a single zone displays the status of all of its parameters, with PV and SP in different colours and a bargraph for intuitive indication of shifts.

An icon constantly signals zone status and any fault conditions, such as input interrupt, short circuit, partial or total load interrupt.

If the password level is compatible, the SP, alarm thresholds, AUTOmatic/MANual status can be changed and the zone switched on/off from this page.

The various pages can be selected directly from the touch screen and, with the 3.5” model, also with 6 mechanical keys with pressed key feedback.

The ability to name and save entire recipes of work parameters for all of the zones provides quick and simple management of device setup for various processes and guarantees error-free operation at all times.

The upper part of the graphics page displays a number of system icons for immediate access to alarms management, change password, calendar/clock setting, and data and recipe storage pages, and also displays active functions.

Alarms are displayed on specific screens with clear messages and can be recognized and reset with keys.

Four passwords are provided for different protection levels, ranging from maximum protection (allowing only the active setpoint to be changed) to a level giving access to all parameters.
The data storage page lets you save both work parameters and HW configuration parameters in separate files.

Saving the configuration parameters simplifies replacement of an I/O module with Hot Swap functions.

A trend page shows the diagram of up to 8 variables, with different colours, the zooming up to “x 128”, the scale ranging, the possibility to select the sampling time starting from 1 sec.

The data are saved in the internal memory and can be exported in a “CSV” format file to a USB key.

For greater flexibility, GF_LOOPER offers a clock/calendar function that switches all of the zones on/off at preset times and days of the week.

Different types of control can be selected for each zone, from simple ON/OFF to precise Heat/Cool control with individual double PID.

Selection of optimum control parameters for each zone is made easier by Selftuning and Autotuning functions, activated by keys.

GF_LOOPER diagnostics always display any critical process conditions, such as interrupted or short-circuited inputs, and signal total and partial load break with video alarms and physical outputs.

Control of Modbus RTU serial communication signals any communication interrupts.

GF_LOOPER interconnects with other control systems, data storage systems, and supervisors via Ethernet, RS485, and USB ports.

Available protocols: Modbus RTU (Master), Modbus TCP, Profibus DP.

The following functions can be activated for specific applications with hot runners: softstart, control with rapid burst firing for solid state relays, and specific diagnostics to detect unwanted variations in power supply and input breaks, with ability to continue to supply average power calculated during the last 5 minutes of operation.

Choice of integrated or distributed control architecture makes GF_LOOPER a flexible solution adaptable to equipment of different sizes and with different performance and modularity requirements.

Advanced control algorithms provide excellent management of process variables.
Various types of control are possible: ON/OFF, P, PI, PID, both heat or cool only and heat+cool.
In addition, cooling can be set by specifying the fluid used: air, oil, water.
Calculation of the best process parameters is extremely rapid and efficient thanks to the use of sophisticated automatic tuning processes.

The use of advanced tuning lets you check the best PID parameters under all conditions.

Two alarm thresholds (minimum and maximum) for each zone.
For each alarm, you can select:
* the control variable to be assigned
* the threshold value
* the hysteresis value
* 5 properties (with latch, disable at power-on, deviation/symmetrical, absolute/relative, direct/inverse).
* LBA, HB, SBR alarms can be set; the presence of the alarm is displayed on the screen via LEDs.

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