Modbus address register exchange between Melsec-Q series PLC and ME96SSHA-MB Power meter

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Please assist me with the following; regarding the ME96SSHA-MB Power meter data transition with Melsec-Q series PLC;

We acquire to read various values on dedicated Modbus storage address registers at the simultaneous into a Melsec-Q series PLC via Modbus (TCP or RTU)  for calculation purposes.

Naturally, since the reading of these variables are to provide accurate instantaneous results, it is a requirement that these values are to be read at one scan.


However, as can be seen below, there is a gap in address register range – of which, if all of these are scanned simultaneously, yields an exception error when read.

This error is only avoided by scanning these data sets separately – which is not ideal for our application – since accuracy in calculations is imperative.

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Does it matter since the gap is obviuously located between system setup range and measurement range? What I mean is that 754...763 is multiplier factors, model code and so on which obviously does not have anything to do with realtime measurement, while 768...788...xxx is the realtime measurement area where you want to do the high-speed calculation.

So in other words, I would read-out 754...763 during startup of system, and then continously read 768...xxx for measurement purposes.

Or am I missing something here?

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Thank you for your reply. In short, one can see that the variables that is being applied in the setup range - that variables such as the multiplication factors, e.g, is required to correspond to that of the real-time variables being read (current, voltage, etc). This is the case since there are various layers with their accommodating factor value. The correct multiplication factor is required to instantaneously correspond to that of the applicable real-time set of variables. 

It can therefore be seen that it would be ideal if it would be possible to scan the set of variables in one-go and synchronized. 

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