Programming Level 1 : Control; Programming Level 2 : Configuration - Chauvin Arnoux Statop 4849 Manual De Instrucciones

3.6

Programming level 1 : control

NOTE : The following procedure assumes that the SEL parameter is set to 0. The SEL function is
explained fully, later in this section. Basically the SEL function allows the user to configure which of the
parameters are available for selection in the lowest security level of the STATOP 4849. The order of the
following procedure will change if SEL does not equal 0, but all descriptions are still valid.
1. Press the Scroll key and hold in for longer than 6 seconds (16 seconds maximum), « ASP1 » will be
shown on the PV display. This is the alarm setpoint, it can be changed if necessary by using the
Raise and Lower keys. The alarm can be set to positive or negative to reverse the direction of
operation of the output relay.
2. Press the Scroll key once. " rr " appears in the PV display. This indicates the Ramp Rate (if used). A
single stage ramp function may be used to allow a " Soft Start " to the process. The ramp rate
parameter allows the process value to change at a predetermined rate and is adjustable in the range
0...200°C/minute. If the ramp rate is not being used, the " rr " parameter should be set to 0. Please
refer to § 3.10. for a full explanation of the Ramp Rate function.
3. Press the Scroll key once, " oFSt " will appear in the PV display. This stands for " offset " and is used
as a manual Reset (integral time - see point #10 below). Leave set at " 0 ".
4. Press the Scroll key once. " SHiF " appears in the PV display. This is the shift function, which allows
small compensation for system calibration errors. If for instance, the controller reading is shown to be
2 degrees high, entering a value of -2 for Shift will correct the problem without the need for recalibration.
5. Press the Scroll key once. " Pb " will appear in the PV display. This is the proportional band setting,
and may be changed if necessary by using the Raise and Lower keys. A note of the existing setting
should be taken prior to making any changes. Proportional band influences the sensitivity of the
control loop. If the band is two wide, control will be slow, if it is too narrow oscillation and overshoot of
setpoint will occur.
6. Press the Scroll key once. " tl " will appear in the PV display. This is the integral time setting (or reset).
Once again, the value may be changed by using the Raise and Lower keys. Integral action creates a
" shift " in the controller output to compensate for offset caused by the proportional band action. If the
integral time setting is too low, instability or oscillations in the process will occur. If too high, slow
response will be noticed.
7. Press the Scroll key once. " td " will appear in the PV display. This is the derivative time (rate). The
derivative action varies the output of the controller compared to the amount the process is away from
setpoint. It steadies the control in the shortest possible time. If the derivative time is set too high, slow
response or oscillations will occur. If set too low, high overshooting of setpoint will occur.
8. Press the Scroll key once to return to normal operation.
NOTE : This may all sound complicated, and in most cases it is not necessary to know of all the control
parameters. Each of the control parameters interacts with the other, and this is why it is best to at least
allow the controller to auto tune to obtain some initial settings.
3.7

Programming level 2 : Configuration

The STATOP 4849 controller is usually with default settings (see § 3.3.). If you should need to change
your controller's configured, this is easily achieved in the field.
1. Repeat the steps outlined in preceding section.
2. When you have scrolled through to " td ", press the Scroll key for at least 6 seconds (16 seconds
maximum). " LoCL " will appear in the PV display. Leave this set at " 1 ". Setting to " 0 " locks out the
front panel to prevent unauthorised tampering of setpoint, etc.
3. Press the Scroll key once. " SEL " will appear in the PV display. This is the Parameter Selection
Function and determines which parameters may be accessed at the lowest security level, i.e. accessible
without having to hold the Scroll key in for the 6 second period (level 0).
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