Yokogawa RotaMASS 3-Series User Manual

Page 156

APPENdIX 5. PId BLOCK

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IM 01R04B05-00E-E 3rd edition July 30, 2010 -00

When configuring a simple PID control loop by
combining a RotaMaSS with a fieldbus valve
positioner that contains an ao block, follow the
procedure below to make the settings of the cor-
responding fieldbus function blocks:

1. Connect the aI block and PID block of the

RotaMaSS, and the ao block of the valve
positioner as shown above.

2. Set MoDE_BLK.target of the PID block to o/S,

and then set GaIn, RESEt, and RatE to ap-
propriate values.

3. Check that the value of MoDE_BLK.actual of

the aI block is auto.

4. Set MoDE_BLK.target of the ao block to

CaS|auto (meaning "CaS and auto").

5. Check that the value of BKCaL_In.status of the

PID block is not Bad.

6. Check that the value of In.status of the PID

block is not Bad.

7. Check that auto is set in MoDE_BLK.permit-

ted of the PID block.

8. Set MoDE_BLK.target of the PID block to

auto.

When finishing all steps in order, the PID block
and ao block exchange the respective informa-
tion and initialize the cascade connection. Con-
sequently, the value of MoDE_BLK.actual of the
PID block changes to auto and automatic PID
control starts.