Yes, CONTROL = CONTROL for loop 1
No, math functons and 8 segment characterizer are not needed, they are used for pressure compensated 3 element control.
> character used for navigation through menus, not as 'greater than'.
** asterisks are critical settings **
1) ALGORITHM LOOP Rate
19 X 23 X cannot be used because that setting is limited to 2 HLAI (high level Analog inputs)
see page 82 (paper) Algorithm Data set up Group:
** For 3 high level analog inputs, the setting for Loop Rate = 1 6X 2 3X **
2) The use of the square root function in the UDC depends on whether the transmitter(s) are configured for pressure output (which uses 'square root' on the UDC) or square root within the DP transmitter (which uses 'linear' setting on the UDC).
Most modern DP transmitters can be either pressure output or flow output (where the pressure is square rooted).
If the transmitters are square root output, then you do not use the square root function in the UDC, you
use the "linear" setting in the UDCs's
INPUTx > XMITTRn parameter.
3) PID loop action: (direct or reverse)
Feedwater flow (loop 1) is reverse action: as steam flow FT PV decreases, PID calls for higher output.
Drum level flow (loop 2) is reverse action: as the level decrease the PID calls for higher output
** Your CONTROL2 > ACTION = direct. Should be = reverse **
4) Ratio & Bias settings (under INPUTx)
Your ranges of 0 to 28 for feed water flow and steam flow seem problematic.
The summer's output = the remote setpoint of loop 1, the feedwater loop.
Since the output of a PID loop ranges from 0-100, and that value has the steam flow value added to it, there's a problem feeding numbers of this range to a loop whose PV range is only 0 to 28.
Although the inputs can be scaled by a ratio and bias setting, the output of PID loop can not, it will always be 0-100%.
I suspect the work-around is to scale the feed water and steam inputs up by some factor, so that the range is greater then that of the PID output. But my notes aren't here, I'll have to check on Monday.
(The ratio and bias settings under INPUTx apply a Y = Ax +b correction to the input;
where ratio = A and bias = b)
5) Output rate (under CONTROL and CONTROL2)
Output rate should be disabled, unless you have a compelling reason to define the output slew rate.
The parameters that follow Output rate, PCT/MIN UP and PCT/MIN DOWN affect the output slew
rate.
6) PID B is sometimes used for loop 2 drum level
Algorithm > CONT 2 ALG + PID B or PID A
PID B definition from manual, page 86 paper; 97 pdf:
PID B: Unlike the PID-A equation, the controller gives
only an integral response to a setpoint change, with no
effect on the output due to the gain or rate action, and it
gives full response to PV changes. Otherwise controller
action is as described for the PID-A equation.
7) "SP Track" parameter under CONTROL
Feedwater loop 1 sometimes uses PV track, where local SP tracks PV
when in manual mode.
8) Setpoints:
Drum level Loop 2 uses a local setpoint
Feedwater flow Loop 1 uses a remote setpoint from loop 2's output.
The manual suggests that such is automatically configured on UDC 6300, page 175:
"Loop #1 Remote Setpoint is fixed as loop #2 output."
I'm not sure what CONTROL2 > LSP = 1 means in a cascade context..
Dan
