PAS600L - Time to Refresh - IEM3155

[Kevin08]

Hello Community !

I'm working on a project which embeded PAS600L device & I need help.

I'm looking to know the minimum time periode (in sec) we can ask to the PAS600L for energy consumption measured by 22x IEM3155 linked in DaisyChain ?

We're looking for less than 2s.

Thanks in advance,

Kevin

[Thierry_Baudard]

Hello Kevin,

My understanding is that you want to collect the 22 meters in a time interval of 2 seconds.

It means that the average time will be 2s/22=90 ms to request each meter so  it is a demanding architecture very close  to the maximum performance of a modbus SL fieldbus ! (or too high...?) 

It depends of the Panel Server of course but also of the response time of the iem meters themselves.

So not possible to definitively answer to your question without test on the architecture !

Some advises:

  - find the "just enough" inter frame delay in the PAS 600 parameters (default settings on PAS=10 ms but depending of the performance of the downstream products, this time must be sometime increased up to 50ms or more )

  -  Upper modbus TCP client must request each meter ONLY for the energy modbus registers (and not for other registers!)

  -  use the Panel Server as a transparent gateway without discovery of the iemmeter in the Panel Server web page . the discovery in Panel server generates an additional and periodic traffic to check if the downstream products are still connected

(use the discovery feature when you commission your installation to check that iemmeters are reachable ... but delete it in the Panel Server before  connection of  the upper modbus TCP client)

  -  keep in mind that the disconnection of one iem meter, will generate time out issues with impact on the polling of the whole installation

One question: typical collecting time interval for energy monitoring is X minutes. What is your use case ? is it for  control ? / load shedding ? other?

BR  

[Tun]

Thanks for your inputs @Thierry_Baudard .

Not sure it is relevant to ask PME's "Daisy-Chain Calculator" in this forum?

How does PME's Daisy-Chain Calculator defines a specific response time (e.g 2 sec) that we are discussing here?

As far as I understand, it does only defines the maximum number of downstream devices in a single daisy-chain. 

Best Regards

Tun