Decimal Point; Control Mode - gefran 600 User Manual

When changing the decimal point the parameters Lo.S, Hi.S, oFS, Lo.L and Hi.L are affected and also the control and alarm setpoints! Make
sure to check and adjust all these parameters after changing the decimal point.
For example changing the decimal point from 0 to 1 will change Hi.S from 1000 to 100.0. As a result the unit will register a sensor fault if the
temperature exceeds 100°C. Set the HI.S parameter to 999.9 to rectify this.
The input scale is defined by the parameters Lo.S and Hi.s in the CFG menu.
If the temperature falls outside the scale defined by Lo.S and Hi.s, the controller will indicate a sensor fault.
Changing the input scale also affects the proportional band in PID control because h.Pb and c.Pb are a % of the input range.
The Gefran 600 controller allows changing of the sensor scale.
For standard temperature sensors (thermocouples, Pt100...) the Lo.S and Hi.s parameters should normally correspond with the minimum and
maximum temperature scale of the particular sensor, as listed in the input table.
Example: for a type "J" thermocouple Lo.S=0 and Hi.s=1000 .
NB: When a decimal point is selected, these parameters are affected and must be reset. For instance on a sensor input type "K" setting
dP.S=1 in the InP menu will change Lo.S=0 to 0.0 and Hi.s= 1300 (no decimal point) to130.0 (with decimal point) . When the temperature
rises above 130.0°C, the controller will thus indicate a sensor fault. The Hi.S parameter must therefor be reset to Hi.s=999.9 to eliminate this
problem.
For analog inputs (e.g. 4-20mA or 0-10V) Lo.S and Hi.s represent the zero and span of the input signal.
Example: input type is a temperature transmitter 4-20mA and a zero and span of -5-°C and +100°C respectively (4mA representing -50°C
and 20mA representing +100°C).
The correct setting for Lo.S= -50 and Hi.S= +100. If a decimal point is set (dP.S=1) then the correct setting is Lo.S= -50.0 and Hi.S= +100.0
For custom lnputs the calibration (32 step) is performed in the LIN menu. The steps are numbered from 5.00 to 5.32
Example: Custom input tyP.=53 (1-5V), corresponding to a reading of 0 to 150°C
Procedure:
divide the input signal range by 32: (5-1)/32=4/32=0.125 V
enter the corresponding value to be displayed for each step. Since the curve is not linear, look up the matching reading for each input value
on the graph or table for the input device.
step 5.00 (first step): enter value for input signal 1V ( in this case "0")
step 5.01 (second step): enter value for input signal 1.125V
step 5.02 (third step): enter value for input signal 1.250V
... continue through all 32 steps, increasing the input signal by 0.125V per step and entering the corresponding value to be displayed.
step 5.32 (final step): enter value for input signal 5.0V (in this case "150")
Now set the input range in the InP menue as follows: Lo.S=0 and Hi.S=150. This will define when the input signal is out of range.
The control type is determined by the Ctr parameter in the Hrd menu.
Most commonly used setups are:
Ctr=6 PID heating (factory default setting)
Ctr=9 ON / OFF heating (the h.Pb parameter in the CFG menu sets the hysteresis, normal setting: h.Pb=0.1)
Ctr=10 ON / OFF cooling (the c.Pb parameter in the CFG menu sets the hysteresis, normal
setting: c.Pb=-0.1)
Ctr=12 PID heating, ON/OFF cooling (c.Pb sets hysteresis, same as above): This control
mode is ideally suited for extruders with air cooling using fans. In this mode the
controller prevents overlap of the heating and cooling output.
The deadband (temperature band between heating and cooling) is set by adjusting c.SP in the CFG menu. Because overlapping of heating
and cooling is prevented by the controller, it is possible to set the deadband very small ( e.g. c.SP=0.2), thus achieving very accurate control.
This control mode is preferable to normal PID heating (Ctr=6) using the alarm function for cooling. Normal PID heating with Alarm usually
necessitates a large deadband (5-10°C) to prevent overlapping of the heat / cool operations.
Please note: you have to enable the cooling output (Out1) by setting rL.1=1 in the Out menu.
Also check that the heating output is enabled by rL.2=0 (alternatively rL.3=0 for analog control).
You also have to set the deadband c.SP in the CFG menu.
Ctr=12 PID heating, PID cooling: This control mode is ideally suited for applications where the
cooling medium (air, water, oil) is controlled via a solenoid valve or motorized valve.
The deadband (temperature band between heating and cooling) is set by adjusting
c.SP (e.g. c.SP=0.2) in the CFG menu.
The PID parameters for the cooling function are automatically set by entering the
relevant cooling medium in C.ME in the CFG menu (e.g. C.ME=2 for water cooling).
Check the note above regarding enabling of the cooling output.
8 • DECIMAL POINT
9 • INPUTS (SCALE, TYPE)
• Standard Sensor
• Analog Inputs
• Custom Inputs (user calibration)
10 • CONTROL MODE
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