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We are trying to built up communication of power meter pm-710 with egx-100.

We are trying to built up communication of power meter pm-710 with egx-100.

We have 10 power meters connected in daisy chain and then all the power meter are connected with egx-100. It is written in the manual of EGX-100 that its supports up to 32 devices.

The problem is that we can only get up to 8 power meters values we could not get the values and response of THIRD LAST and LAST power meters (power meter 8th and power meter 10th).

Our communication settings are as follow:
Baud rate: 4800
Parity: none
Tim out: 1 sec

Further we have change the baud rate e.g. (2400 9600 19200) and time out egx-100. but we are not getting the values from the last two power meters of the daisy chain and we have changed the setting of power meter but still same result.

Egx-100 is a gateway to convert MODBUS to MODBUS TCP/IP. We are getting the values from all power meter when they are connected in MODBUS protocol.

Regards,
GENJUA

By John Correa on 18 November, 2009 - 4:28 pm

Check the error message type in your EGX100. If the error message is TIMEOUT may be something wrong with the wiring or the termination resistor is plugged in that station. Try first to establish communication with your conflictive station with your EGX to isolate the problem.

The EGX100 supports a total of 32 open TCP/IP connections at one time with the 2.7 firmware. It appears that your application that is communicating to the EGX100 may not be properly closing the connections when done. To verify this restart your application and try to communicate first with one of the devices that you are currently having issues with. If this works, continue adding the other devices to your application to see when communication stops.

In addition the diagnostic webpages will provide you information about the Modbus Serial network that can be used for troubleshooting.

You can determine the number of active Ethernet connection from the diagnostic webpage on the EGX100.

John Correa, sometimes i get the error which is NEGATIVE ACKNOWLDGE and sometimes the error is DEVICE TIMEOUT.

i want to mention one thing here which is that when i connect the daisy chain with MODBUS i get the response from all the 10 power meters. but when i connect the daisy chain with egx-100 and i do not get the proper response. so now one thing is clear that there is no issue of connection.

Robert Willis, when i connect the devices one by one i get the good response from egx-100. but after adding the 8th 9th and 10th device, the response get bad.

Further i will check the firmware and will follow your instruction and then i will post the result here.

Thanks to both of you.

Regards,
GENJUA

Hello,

Jumping in the middle here and I might have missed something.

How about termination resistors? I assume this is 485 on the device side. Or am I missing something?

Good luck,

Mark
http://www.peakhmi.com/

By John Correa on 19 November, 2009 - 7:10 pm

Only thing that can suggest (by now) is that you change the update rate of your MB_TCP driver. May be that the amount of data from your devices is to big to be sent back by the serial line (9600 bps) and the EGX is not able to process the incoming ethernet requests may be discarding some of the request.

Try to decrease the inter-request rate or try to read fewer parameters from your devices.

Mark, ya i try with end terminal resistor as well.

John Correa, know i am reading only 2 parameter only but still same result.

Robert Willis, i am really looking forward for your reply because my firmware was 2.5.

(1) today i update my firmware to 2.7

(2) now am trying to configre the device which was not giving me response in the daisy chain. but i could not get the response from that device when its is connected alone with the egx-100.

(3) i have changed the device i put some other "NEW" devices and i get the response from the EGX-100 but when i connect the device in the chain then the whole communication disturbed.

Regards,
GENJUA

By John Correa on 20 November, 2009 - 6:00 pm

In the EGX you have the option (web page) to read parameters from individual devices. Try it one by one manually. If you can do this, then the problem is your visualization software. Also the majority of MB_TCP driver may have a "debug mode" in which you can see the log file an analyze each transaction between your software and the EGX. By the way what kind of software are you using.

John Correa yes we know about the webpage to read the parameters. We did the same to access each device one by one. We are getting good response until 7 devices are connected but when we add the 8th device the response get bad.

We can access maximum 8 power meters in the daisy chain, and there are 10 power meter PRESENT in our chain for testing. We have to connect 22 power meters in future for our project.

We are using PcVue to access the devices. We have also used POWERVIEW and MODBUS TCP/IP tester but we can access maximum 8 devices.

Looking forward for your support.

Regards,
GENJUA

By John Correa on 21 November, 2009 - 8:10 pm

One test that you are missing is checking the load to the EGX RS-485 port. May be that you are exceeding the load capacity of the port. You can use a RS-485 repeater to relief the port or try checking the signals with an oscilloscope connecting station one by one.

By Schneider italy on 22 November, 2009 - 6:13 pm

Hi Genjua,

I know very well your problem. We normally suggest to connect a maximum of 6-8 devices for a continuous polling. EGX or ETG could manage a maximum of 32 devices on modbus RTU but 16 TCP connections. You have to consider that to READ/WRITE data from a single devices, two TCP connections will be opened. That's why you could read data from only 8 devices (16/2 = 8).You have to say to PCVUE to read devices with delay not simultaneously or buy another EGX

By Wassim Daoud on 23 November, 2009 - 12:20 pm

Hello Genjua,

I wonder what is whole length (circumference of the daisy chain) of the transmission cable you are using? What does the meter's manual say about the maximum distance for 4800 baud rate transmission?

Also i would check the cable's resistance type as it has a big factor.

Hope this was helpful

Wassim Daoud
Global Solution Architect

I suggest you take a look at the time-out of the slaves. Try putting the time-out of the 9th and 10th slave at 2 seconds.

Hi,

I have similar problem here using EGX. I have 13 devices (relays) connected in daisy-chained to EGX. If all device are powered, i have good connection. however, if 1 of the device is off, the whole loop is affected and loses communication to others, though only 1 is off.

I would like to solicite your idea on what went wrong.

thanks,
rda

Schneider's Technical library:

http://www.schneider-electric.us/support/product-support-resources/technical-library/?event=category&cat=0b008926804d0356

lists two documents in English for the EGX100, one called installation instructions 63230-319-200, and the other the EGX100's Users Guide, 63230-319-204.

Problem is, both are identical in content.

The user guide indicates termination and biasing on what appears to be a terminal block on a graphic image of the device, but nowhere is there an explanation of the details of the bias or termination. Maybe it has switchable termination that is or isn't activated, but I'll never know. The manual isn't on the web site. And I even got suckered into registering to try to access the installation guide. Thank heavens my clients don't use Schneider PowerLogic.

So, sorry, I'm stuck. Good luck, guys, with such poorly documented devices.

RDA which software you are using for COMMUNICATION?

well all you have to do is just adjust the timeout.

i was facing the same problem in the beginning then i adjust the timeout after that i got the goood response.

Regards,
Genjua

Rda: Based on your description it appears that you do not have the time-out set properly on the device that is polling the meters on the RS485 Network. Modbus is a Master Slave Protocol and communication to each device must finish or timeout before the next one starts. When you are using a Modbus TCP/IP to Modbus bridge in the link, you have both the "Client Timeout" and the bridge timeout that can be adjusted. Typically the client time-out should be longer than the bridge time-out. In addition, please verify that you have the proper termination and bias enabled for your network configuration.

Thanks Robert & Genjua, typically what is the proper setting for client & bridge timeout?

It depends on the number of devices (slaves) and the number or parameter you read, and also on your communication configuration parameters.

If you do not need to refresh your data fast, try first with a slow rate, like 1 second or more, if everything goes fine, try decrease that time until you get what is best for your application,

Best regards,

Gonzalo Jimenez
http://www.linkedin.com/in/gonzalojimenezyamasaki
http://sites.google.com/site/gonzalojimenezyamasaki

Hi Genjua,

I too will soon implement a similar project with 9 PM 710 and 4 Micrologic 5.0P, all linked in a daisy chain to an EGX 100 and to a PC running powerview.

I would be grateful to have your help on that matter regarding how connections are made, the setting of the egx and software etc for successful comm (i have not received the powerview kit yet).

Plz feel free to contact me directly at jordan.choo [at] umail.uom.ac.mu

Your help would be highly appreciated.

Yonick

Hi genjua,

I too, i'm implementing a comm. network between several PM 710, 5.0P and 5.0H via EGX 100 to powerview with TCP/IP.

Connections so far has been ok. The prob. is with launching the powerview...it says that i need to start the powerlogic network server first and i cannot do so, even after dloading and installing the patch given by Schneider electric.

Any recommendations on your part, plz?

when i start it manually, it says "error 1053:the service did not respond to the start in a timely fashion..." !!!!!???