IDEC MICROSmart FC6A Series, Ladder Programming Manual

Page: 417 / 604

FC6A S
ERIES
MICROS
MART
L
ADDER
P
ROGRAMMING
M
ANUAL
FC9Y-B1726 19-27
19: PID C
ONTROL
I
NSTRUCTION
Settings
The PIDD (PID with Derivative Decay) dialog box contains the Device tab, Controller tab, and Tuning tab.
The devices used with the PIDD instruction are configured in the Device tab.
The initial values of the PIDD instruction parameters are configured in Controller and Tuning tabs.
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Device tab
1. S1 (source 1): Control Register
Specify the first device of the data register range that stores the PIDD instruction control parameters.
Starting from the specified data register, 100 words of data registers are used. The devices that can be specified as data
registers are data registers D0000 to D7900 and D10000 to D61900.
When the PIDD instruction initialization input is turned on, the control registers are initialized with the values set on the
Controller and Tuning tabs.
For the control registers, see "S1: Control Registers" on page 19-34.
2. S2 (source 2): Initialization Input
Specify the device that initializes the PIDD instruction control registers and control relays.
The device that can be specified as the initialization input is an external input or internal relay.
The parameters set on the
Controller and Tuning tabs in the PIDD instruction dialog box are the initial values of the PIDD
instruction control registers and control relays. These initial values are downloaded to the PLC as the user program and stored in
the PLC's ROM. When the initialization input is turned on, the initial values of the PIDD instruction in ROM are stored in the
control registers and control relays.
When the initialization input is on, the initial values are stored with each scan. To only initialize the values one time, use the
initialization input in combination with the SOUT (single output up) instruction or the SOTD (single output down) instruction.
3. S3 (source 3): Control Relay
Specify the bit devices that will control PID control and store the status of PIDD instructions.
Starting from the specified internal relay, 32 internal relays are used. The devices that can be specified are internal relays M0 to
M7960 and M10000 to M21210. Special internal relays cannot be specified.
The role of each control relay bit is different. The operation of the PIDD instruction, such as direct control action/reverse control
action, derivative action enabled/disabled, self tuning enabled/disabled, and auto mode/manual mode/cascade control mode,
can be toggled by turning the corresponding bit on and off.
For the control relays, see "S3: Control Relay" on page 19-21.
4. PIDD No.
Assign a unique number from 0 to 31 to identify each PIDD instruction.
When performing the cascade control, specify the master PIDD instruction by its PIDD number.
1.
2. 3.
4.