ION ModBus Master for ModBus RTU Wrapped in TCP

[Sepehr_Zarrabi]

I have an application where a number of ModBus devices (Enercept meters) are connected serially to an EGX100. Is it possible to use the PM8000 to do data logging for these devices over the TCP/IP network?

The alternative is to use an EGX300 (or Com'X510) to log the data and use FTP and ETL to import into PME but I am trying to get away from having to use the ETL if possible.

[Adam_Hardman]

Hi Sephir,

If I understand correctly you want to use the PM8000 for modbus mastering of serial modbus devices. That is possible with the PM8000. If you refer to the PM8000 User Manual (Chapter 9 - Protocols) you will find details about the prequisites. The set up of the PM8000 can be done using ION Setup.

Adam

[Hal_Etheridge]

Another option is to just use PME to do the logging...  There is a driver for the Enercept so you just need to add the device in Management Console and possibly configure SW logging in either the driver or VIP.  Since this is a device in PME all the logged data will automatically appear in the database without the need to ETL or do any other extra steps.

[Sepehr_Zarrabi]

Adam Hardman Thank you for the response. The ModBus RTU devices are not directly connected to the serial port of the PM8000. The ModBus RTU devices are connected to an EGX100, which is connected to the same TCP network as the PM8000.

Can the PM8000 ModBus master the serial devices by going through the EGX gateway? If so, can you please specify the settings I need to use in the PM8000?

[Yu_Diao]

Sepehr Zarrabi,

We did similar applications using 7550RTU or just 7550 meters, and they worked fine. Since PM8000 is also based on ION, it should work, there are just a couple modules needs to be set up, I think there may be a technique article discussing about ION meter Modbus Master over TCP already. On PM8000 manual, chapter 9, page 59/188, there is a drawing for your reference.

I would recommend this solution based on my previous experience. The advantage for this is: it provides kind of "on-board" logging for the low-end Enercept meters as long as you can keep the network between the PM8000 and EGX100 is on (i.e the server could be offline or the network to the server could be off).

Regards,

[Hal_Etheridge]

If you use custom downstream labels for the Modbus master module outputs then any data logged by the meter on behalf of the Modbus slave devices can be automatically mapped by PME to those devices.  There are label length limitations on the device that can make this hard to do in practice sometimes though.  An alternative is to setup a logical device in PME to map the logged data from the downstream device registers to the logical device.  The end result is the same in the database but the amount of work (and where the work is done) is different.

[Yu_Diao]

Yes, Hal is right about the "label length", it is a limitation posed by the meter hardware (I think), you cannot use "_" ("-" actually works...) in the framework. In most of my applications, I was able to convince the customer to just accept the shorter names. In other cases, I used "downstream device assistant" to change the name to whatever you want.

Also, another advantage to "logic device" is: the RTU/ION meters only provide logged data for Enercept, I still got to utilize all existing meter template for Enercept meter and the real time data will be provided by Enercept device driver and it saved me a lot of time to create meter diagrams for each individual meters.

[Sven_Ortmann]

Hello,

this week I was confrontation first time to configure the pm8000 as a modbus gateway for some IEM3155 slave devices.

I didn't get the communication work (neighter communication with slaves on ion setup nor PME 7.2.2)

I tried different setups of pm8000 without success.

Any dokumentation on how to configure the pme 8000 correctly to work as a modbus gateway for iem3000 devices to implement im PME software?

thank you

[Robert_Lee]

To activate the PM8000 Modbus Gateway feature, you will need to set the serial port settings to match the slave device settings, set the Comm port protocol to "Modbus Master".

In addition, you will also need to connect to the PM8000 using ION Setup to switch on the Modbus Gateway functionality via the Setup Assistant (go to Communications -> Basic Ethernet -> TCP/IP tab and modify the Modbus Gateway setting to "COM1" which should show COM1 (Modbus Master) assuming you set the protocol to Modbus Master already).

[Sven_Ortmann]

Hello Robert,

thank you, but I thing all these settings are set correctly. I will double check in next remote session.

[Robert_Lee]

I also believe that the iEM3xxx devices have a default (or maybe even fixed) port settings of Even Parity instead of our ION default of No Parity so make sure all devices have identical settings.

[Sven_Ortmann]

hello, yes I saw it and configured it correctly, but no communication until now. Strange thing, in pme with ion port a communication works with the pm8000

[Robert_Lee]

That likely implies that PME is successfully communicating directly to the PM8000 via IP Port 7700.  It sounds like port 502 might have an issue though. 

You could try to either use ION Setup or some other Modbus tool to try to connect to the PM8000 directly using Modbus TCP (using ID 255).  This would indicate that at least the Modbus TCP portion is functioning correctly.  Assuming the Modbus gateway portion is working, you might need to see if the RS-485 LEDs are blinking when attempting to reference one of the iEM devices (this would require access to the back of the device and likely opening of the panel).

When creating the gateway site in ION Setup, make sure you select port 502 for the gateway as the iEM devices don't communicate ION.