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/* be bumpless and will use the current Process Variable value as the
/* new setpoint.
/* The Status variable indicates when the Manual control mode is active.
/*
/* At startup in the Manual control mode, the output will be held at
/* its current value.
/*
/* At startup, in the Automatic control mode, the output will slew
/* from its initial value towards P_factor * Error at a rate determined
/* by the Integral control constant (I_out is initialized to cancel P_out). */
/*
/* For process monitoring, data may be sent to the FIFO and current
/* value table (CVT).
/* by the History_mode variable.
/* on 'n', where n is the algorithm number (as returned by ALG_NUM, for
/* example).
The first value is placed in the (10 * n)th 32-bit word of
/* the CVT.
The other values are written in subsequent locations.
/*
/*
History_mode = 0:
/*
are output to the CVT.
/*
/*
Location
/*
0
/*
1
/*
2
/*
3
/*
/*
History_mode = 1:
/*
summary values are written to both the CVT and FIFO.
/*
tag (256 * n + 4) is sent to the FIFO first.
/*
/*
History_mode = 2:
/*
are output to both the CVT and FIFO.
/*
is sent to the FIFO first.
/*
/*
Location
/*
0
/*
1
/*
2
/*
3
/*
4
/*
5
/*
6
/*
7
/*
8
/*
/****************************************************************************/
/*
/* User determined control parameters
static float Setpoint = 0;
static float P_factor = 1;
static float I_factor = 0;
static float D_factor = 0;
static float Error_max = 9.9e+37;
static float Error_min = -9.9e+37;
static float PV_max = 9.9e+37;
static float PV_min = -9.9e+37;
static float Out_max = 9.9e+37;
static float Out_min = -9.9e+37;
356 PID Algorithm Listings
There are three levels of data logging, controlled
The location in the CVT is based
Summary to CVT only.
Value
Input
Error
Output
Status
Summary to CVT and FIFO.
All to FIFO and CVT.
Value
Input
Error
Output
Status
Setpoint
Proportional term
Integral term
Derivative term
Setpoint Derivative term
In this mode, four values
In this mode, the four
In this mode, nine values
A header tag (256 * n + 9)
/* The setpoint
/* Proportional control constant
/* Integral control constant
/* Derivative control constant
/* Error alarm limits
/* Process Variable alarm limits
/* Output clip limits
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
A header
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
Appendix D
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