COM'X 510 as a Data Concentrator (Not as a Transparent Gateway)

[Tun]

Dear Folks,

Can COM'X 510 be configured as a Data Concentrator , NOT as a Transparent Modbus Gateway?

That means Power Monitoring Expert (PME) can see COM'X as a Device (PME won't be able to see the Modbus Slaves connected to the COM'X) ?

Thank you

Tun

[Romain_Polette]

Hello @Tun , 

This is explained in the Com'X User Guide.

Explanation above is also applicable to PME.

If you want to use Com'X as a Gateway for PME :

1. Declare the Com'X 510 IP as a "Site" under PME
2. Declare each connected device (Modbus Slaves or Ethernet Slaves) with their "Local ID"

By doing this you will be able to see the device under PME.

Regards.

[Tun]

Thank you Romain for the quick input.

Pls find Connection Setup screenshot and my expectation is to use a single IP address (COM'X IP) to poll "All"  parameters of the devices (slaves) connecting to the COM'X.

(Assuming 1 slave has 10 parameters each and we have 64 devices under COM'X, total parameters = 640 parameters)

As per your comment/COM'X manual , Setting->Communication->Modbus Gateway, those downstream devices(slaves) are able to configure (up to 64 devices). With these configuration, the way I would want to poll those devices parameters are readable directly from "COM'X Modbus Registers".

Sorry that I'm not familiar with COM'X510 and pls correct my understanding if any.

Regards

Tun

[Romain_Polette]

Hello @Tun , 

Com'X has only internal Modbus Register for its Digital Inputs (refer to "Modbus Register Mapping" chapter). To log some data : Com'X is using the Modbus Map of each slave (native model, or custom model). You cannot build a specific Com'X Modbus Map containing the registers of your slaves.

There a specific PME driver for Com'X but only dedicated to get data related to WAGES connected on the Digital Inputs.

PME can poll devices connected to the Com'X (with the Local ID) but you need 1st to declare each device on PME Management Console. 

Another prerequisite is to make the Slave Devices Types connected to the Com'X known from PME:

• if you have some iEM3000 connected to the Com'X it will be easy (iEM3000 is native to Com'X and PME).
• if your devices are customs : you need to create a specific driver with the DTE for your device. In this specific case : 1 custom model need to be created on the Com'X + 1 custom driver for PME.

In any case : you need to declare each Com'X Slave to PME. If you have 64 devices connected to the Com'X, you need to add 64 devices in Management Console.

PME cannot read the data logged inside the Com'X. One way to transfert Com'X logged data into PME is to make the Com'X publish data in .csv and use the ETL to transfert the data into PME database.

Regards, 

[Tun]

Thank you again Romain for the detail. Very Clear:). 

Last questions:

1. Does PME see COM'X 510 (connected with 64 devices) as 1 device or 64 devices ?

    (COM'X declared as a Device, Not a Site, in the Management Console)

2. Is there any limitation on the max number of Modbus registers COM'X can poll from a device?

(Assuming COM'X is connecting to a single device which has 2000 parameters)

Regards
Tun

[Romain_Polette]

Hello @Tun , 

1. You can declare the Com'X as 1 Ethernet Device in PME. You need to use the device "ComX (WAGES)". But in this case you will be only able to log and monitor the Digital Inputs of the Com'X510. Devices connected to the Com'X cannot be seen. Any other device connected to the Com'X need to be declared under PME Management Consol.
2. I cannot answer what could be the behavior if you poll a device with 2000 registers. All will depend on the polling frequency and the number of the devices. If you poll the registers every hour for 1 device: I think you will not encounter any issue. If you poll the 2000 registers for the device every minute you may experience errors with the Com'X. If you poll 2000 registers for 5 devices : it will be also difficult. @Randi_Dolan do you have some advice about this config ? For example how many registers are polled if you connect one MTZ to the Com'X510 ?

Regards. 

[Tun]

Hello Romain,

Thank you again for the quick replies.

I'm clear with your answer on point: 1.

For Point:2, our requirement (tender stage) is COM'X to read and log all 2000 parameters from a single device with 15-minute interval (both read and log frequency).

I could foresee that it would heavily effect on COM'X performance if a "single" COM'X is handling this 2000 variables.

As such, what would be a "comfortable" number of COM'X qty to read those 2000 variables? 

I am thinking of sharing the load using multiple COM'X.

Regards

Tun

[Randi_Dolan]

Hi Tun,

A lot of factors need to be considered when determining the polling quantity and frequency of downstream devices.  First, how is this device connected to the Com'X?  Is it serially connected?  If so, what is the baud rate?  Next, you will have to consider how the data is being read.  If the read request is for one register and you are doing 2000 requests, this will be a lot slower than if the read request is for 100 registers and you are doing 20 requests.  Also, you will have to consider the device from which the data is requested.  How quickly can the device return the requested data.

Also, one must consider why collecting data from 2000 data points is relevant.  What is the goal of polling/logging all of this data?  Just because data is available doesn't mean it is useful.

Randi

[Tun]

Hello Randi

Thank you for your input.

Typical Connection diagram enclosed for your info.

My understanding is the application does not require 

All BTU meters are MBUS daisy-chained, connecting to the MBUS-MODBUS Converters and logged into COM'X(s) and push the CSV file to PME (in our proposal). 

The requirement is there would be about 2000 parameters to be logged per HDB Building before pushing the data out (via 3G network) to PME (remote server).

Best Regards

Tun

[Randi_Dolan]

Hi Tun,

Again, the feasibility of this configuration will be determined on how the data is obtained.  How will the data be obtained?  Will there be 2000 reads of 1 register?  Or will there be 20 reads of 100 registers?  Or something in-between?  Also, the baud rate of the devices make a difference on how much data can be read in a period of time.  And, how often is the data exported to PME?

I hope this helps your understanding.

Randi

[Tun]

Hi Randi

Thank you again for your input.

I understand the multiple variables that influence the sizing that I am currently seeking.

But for the system sizing during the tender stage where not much details are given/unknown, I am exploring whether we have some form of "rule of thumb" to size the number of  COM'X required

For example, Assuming 300 registers per read, 30 devices in a whole daisy-chain network, 15-minute interval for both polling and logging, 2400 baud rate, exporting CSV file to PME every 5 minute and etc. Not sure this kind of assumption could estimate the number of COM'X required?

Regards

Tun

[Randi_Dolan]

Hi Tun,

Using Modbus, the maximum number of registers that can be read at a time is 125 using Modbus Function Code 3.  Also, a baud rate of 2400 is slow for modern applications.  Most devices default to 19200 and can be configured to go faster than that.  Also, the Com'X can only export data, at the fastest interval, once an hour.  So, data cannot be exported every 5 minutes.  And, using a 3G network, that would be asking a lot to send that data every 5 minutes.

I really think you need to figure out what you're wanting to do to determine if it is feasible.

Randi.

[Tun]

Hi Randi

Thank you again for your inputs and patience too.

I will find out more detail on those variables from relevant parties that you mentioned here.

Again, really appreciate your inputs.

Regards

Tun