Endress+Hauser Proline Prosonic Flow 93 - Page 193

PROline Prosonic Flow 93 FOUNDATION Fieldbus 6 PID function block (PID controller)
Endress+Hauser 193
6.3 Selecting the operating mode
The operating mode is set by means of the MODE_BLK parameter group,
(see Page 210). The PID function block supports the following operating modes:
• AUTO
• MAN
• OOS
• CAS
• RCAS
• ROUT
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Note!
The OOS block status is also displayed via the BLOCK_ERR parameter,
(see Page 201). In the OOS operating mode, you can access all the write parameters
without restriction if write protection is not enabled.
6.4 Setpoint value specification
The PID function block works with different setpoint values (reference values)
depending on the active operating mode:
• The PID function block is in the AUTO operating mode:
The setpoint value of the SP parameter, (see Page 214), is used to calculate the
manipulated variable. This setpoint value is specified manually by the operator in the
SP parameter.
• The PID function block is in the CAS operating mode:
The setpoint value of the CAS_IN parameter, (see Page 202), is used to calculate the
manipulated variable. This setpoint value is copied from an external function block
and read in via the CAS_IN parameter in the PID function block.
• The PID function block is in the RCAS operating mode:
The setpoint value of the RCAS_IN parameter, (see Page 213), is used to calculate
the manipulated variable. This setpoint value is copied from the fieldbus host system
and read in via the RCAS_IN parameter in the PID function block.
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Note!
The range of the setpoint value entry can be restricted via the SP_HI_LIM and
SP_LO_LIM parameters, (see Page 215).
6.5 Damping
Specifying a time in the PV_FTIME parameter, (see Page 212), slows down the reaction
of the internal process variables to changes in the input value IN, (controlled variable).
This output filter is useful where the input value fluctuates greatly. Where a time of 0
seconds is specified, the output value is not filtered.