need s7 program help Urgent

Hello All

On a projecet, i find that network
AN M 89.2
JC M001
CALL FC 17
IN0 :=DB30.DBW228
IN1 :=0
IN2 :=1000
OUT3:=PQW240
CALL FC 17
IN0 :=DB30.DBW236
IN1 :=0
IN2 :=1000
OUT3:=PQW242
M001: NOP 0

When i try find go to location for DB30.DBW228 just find on that network..Anybody have idea where come data to DB30.DBW228.Anybody help me.

Best regards
nec.

The code looks like raw upload from the PLC and the IN and OUT parameters which would normally have text desctriptors have the default IN0, OUT0 etc..

In answer to your question, the Data Word DB30.DBW228 is an input parameter to FC17 at that location, it is not being written to.

Which means if it cannot be cross referenced as being anywhere else, it is either static data entered via the programmer, indirectly addressed or updated from an HMI/SCADA station.

Do you have a documented project file somewhere, which will tell you what the code is doing and what the tags are?

help

dear PeterW

I have upload that program from plc.have not any documentiation.On hmi that data just readble..I sen to you all program..May you help me how come data to db30.dbw228.That data transfered to pqw240

In the object manager, you will find ONE object: DB30, then open that object you will find DBW228, which includes DBB228 and DBB229, in another words: DBX228.0-DBX228.7 and DBX229.0-DBX229.7. You will find the Value .

looks like this is writing to an analog output to operate a control valve or set a setpoint for a VSD.

Some where else in the code something should write to that word then FC17 probably does some scaling a sets a value to the PQW. Do an cross reference and you should find where else it is written to.

I'm sorry I won't be able to look as I am stuck with control logix software at the moment and have no access to step 7.

I would look in the cross-reference for any access to DB30.

It is quite typical to write in STL something like

OPN DB30 // Opens DB30
..
..
L MW300 // this calculates something
L 10
*I
L MW302
+I
T DW228 // This writes the result to DB30.DBW228

However, DB30.DBW228 will not appear in the cross-reference ! DB30 will.

JesperMP said:

T DW228 // This writes the result to DB30.DBW228

Click to expand...

Search the xref for both DB30 and DBW228 accesses.