CHANGIN RELATIONAL EXPRESSION SETTINGS FROM ICS

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MIHIR RAMKRISHNA

How can I change relational expression setting from ICS in YOKOGAWA CENTUM CS-2 SYSTEMS?

We are using a large number of RL (relational expression blocks in the control computations) in our DCS. As per process requirement, the
parameters in teh RL are to be changed frequently. For this the job gets delayed as it has to be done from EWS which an instrument engineer can only do.I tried to change the RL from ICS by reducing the security of RL tag to 1 but it is not possible. Can any body suggest remedy for this? I want to use RL only....
 
Dear MIHIR RAMKRISHNA,

(I've workable solutions for you...)

RL block (Relational Logic) does not have DataItems that is alterable from ICS.

However, BDSET-1 block (Batch Data Set) offers 16 DataItems that operator can input from ICS. Namely, DT01, DT02, DT03, ... ,DT16.

Here's how it can be implemented on EWS Control Drawing...

BDSET-1 tagname = BD001
DT01 = 64.5
DT02 = 23.5

RL tagname = RL001
01 = TAG001.PV : BD001.DT01
02 = TAG001.PV : BD001.DT02

[ ST16 logic ]
C01 = RL001.X01.GE ... Y
C02 = RL001.X02.LE ... . Y
------------+-------
A01 = PMP01.PV.H ... Y N

Therefore, all that is needed here is to alter value of dataitem DT01 & DT02 of tag BD001 to switch pump PMP01 either On or Off.

While the original control logics remains unchanged.

p/s: You can add "touch input" for DT01 + DT02 onto existing pump process graphics MIMIC to make life EVEN EASIER!!!

Goodluck.
best regards,
Ralph
Yoko Tech Support
 
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