MA7200 PLUS Operating Manual
TECO – Westinghouse Motor Company App-1 External PID Control
External PID I Time P2-08 is used to set the integral time (0 – 100 sec.). Setting I to= 0, disables the
integral function.
External PID D Time P2-09 is used to set the differential time (0 – 1 sec.). Setting D to =0, disables the
differential function.
External PID Bias P2-10 is used to set the offset (-100 to +100%).
External PID I Limit P1-09 is used to set the integral limit (1 – 100%).
External PID Filter P1-10 is used to set the filter time constant (0 – 2.5 sec.).
External PID Feedback Un-42 is used to monitor the feedback of the External PID Function.
External PID Input, External PID Output 1, and External PID Output 2 are monitored by Un-43, Un-44,
and Un-45 respectively.
The PID Input and Output 2 can be accessed through Analog Output Terminal AO1 or AO2 by setting the
corresponding parameter Sn-33 and Sn-34 to =12 (External PID Input) or to =13 (External PID Output)
By setting one of the digital inputs Sn25-28 to =31 (External PID Invalid), the External PID function can be
disabled by activating that input. During the External PID Invalid mode, the PID feedback, Input, Output 1,
and Output 2 are equal to zero.
By setting one of the digital inputs Sn25-28 to =32 (External PID Integration Reset), the accumulated integration
error can be reset by activating that input.
2.3 Main and External PID Parameter Interaction
As mentioned previously certain parameters are common to both the main PID loop and the external PID loop.
The following Tables, 2.3.1 and 2.3.2 show the various parameters that are available to be used in the
external PID function when the main PID loop is disabled and when the main PID loop is enabled .
Table 2.3.1 Main PID Loop Disabled
Terminals available for external PID while (main) PID is
DISABLED
(Sn-64 = 0)
Sn-05
Setting
Sn-24
Setting
Sn-29
Setting
Terminals
Available to Ext.
PID
Comment
1
0
0
AIN, AUX
VIN (0-10V) is used as the Frequency
command
1 VIN,
AUX
AIN (0/4-20mA) is used as the
Frequency command
2 or 3
AUX (0-10V)
VIN & AIN are used as the Frequency
command
0, 2 or 3
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VIN, AIN, & AUX
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Cont.