Dear all,
1. I have a question about CR1000 data logger, belong to modbus communication. Can we simultaneusly setup CR1000 ports:
- RS232 of CR1000 (called PORT A): act as modbus Master <----> RS232 GPRS modem (with private IP) <-------> Country region Celtullar GPRS network <------> SCADA software (with modbus serial slave driver).
- CS I/O of CR1000 (PORT B) <------> NL240 ethernet interface module (act as modbus slave) <-----> Ethernet media <---> SCADA software (with modbus TCP master driver).
- SCADA software: Install on the PC with static IP address.
Requirements: PORT A (primary) redundancy with PORT B (secondary). If PORT A fault then system automaticaly switch over to PORT B for transfer data from CR1000 to SCADA. If PORT A change to good then system reverse from PORT B to PORT A..
The reason PORT A act as modbus Master: RS232 GPRS modem have only Private IP (in many country, we can't get publish/static IP with GPRS network!), so that from SCADA system I can't see the IP address to connect to RS232 GPRS. Therefore I have to config PORT A as modbus master!
PORT B have static IP so we can connect derectly by modbus Master (from SCADA).
2. Sumary: Can I setup RS232 port and CS I/O port of CR1000 to simultaneusly transfer data? Or anyone have a better solution for media redundancy as my requirement ?
Thank!
This simple answer is yes, but you should probably read up on the help for the IProute command which you may need to use to ensure outgoing traffic (master-slave) goes out through the desired interface.
Thanks! Have you got a better solution (hardware & software) for redundancy or/and GPRS connection?
It depends on the level of redundancy you need. Having a local network connection in addition to a GPRS/3G connection gives you duplicate levels of hardware and connection media. If you do not have the local network connection you could look at the new RV50 3G/4G modem we are selling. It offers dual network support (only one at a time) plus it also offers advanced features such a VPN support (although we have not tested or support this). Having the modem setup a VPN tunnel is one way of avoiding the fixed IP issue although it needs extra hardware (and knowledge) at your end.
Yes. I need only 2 lines: One line is optical (main) and one line is GPRS (3G, backup). I known that CR1000 can setting for automatic sending data to Lognet via TCP (CR1000 act as TCP Client, and Lognet is TCP Server), or via RS232 (modbus or any??). Could you briefly explain some solutions (lognet or Modbus, or any OPC ...) CR1000 redundancy communication to HMI PC with diagram. Please remember that my 3G network must be using private IP (my country do not support DDNS or publish IP of 3G network!). Thank you so much!
I would not recommend Modbus or OPC if historical data is what you need as neither protocols deal with this well.
If you use Loggernet you can get the logger to check the main path to the Loggernet server is good (using either an IP Ping or Pakbus route check) and the Logger call-back through the main route or backup when needed (changing the way back to the Loggernet server using the IPRoute command). When the logger does a call-back to Loggernet, then Loggernet will collect all data it had not previously collected from that logger, which means you should loose no data even if there is a delay in the switchover or both lines go down for a while. You can get also get all the data in one file if the logger is calling back to one port on the Loggernet server, no matter which route (they would both need to be IP connections).
If, on the other hand, getting real-time data into a Scada package is what you need and there is no possibility of getting a fixed IP 3G service or setting up a VPN tunnel for the GPRS connection, what you have proposed is maybe the only way of working. There are complications as you know. The main one being the Scada program will be the one that has to patch together the data it collects from the two routes. The logger would also need to be programmed to start sending data via the backup route if it detects the connection via the main route is down (using the IPPing command I would suggest).
I
Dear aps,
Yes. I sumary your explain by my understand:
- If using Loggernet, I can program CR1000 to actively sending data to loggernet via TCP/IP (CS I/O port + ethernet module) and/or via 3G (RS232 + modem GPRS) via Pakbus.
In addition: I can using OPC option to provider data to other SCADA if I want.
- If using modbus: I can program CR1000 to actively sending data to loggernet via TCP/IP (CS I/O port + ethernet module) and/or via 3G (RS232 + modem GPRS) via Modbus directly to SCADA with modbus drivers.
But, my SCADA must be program or config task that can redundancy process to received data from 2 routes (from one source CR1000).
What about the delay time of real-time data in 2 solutions above? and the redundancy switch-over time?
Note: I need SCADA because it fexibility in proccess data and report, historical, ... Especialy, easy to connect from subsystem to the centre system.
Thanks!
To answer your questions:
1) although a rather dated standard I believe you could use our OPC package to make data collected by Loggernet available to the Scada package.
2) The logger does not send data using the Modbus protocol to Loggernet (it would use our own Pakbus protocol). If you did not want to use Loggernet, you could program your SCADA system to receive data from the logger normally using Modbus. If the connection goes down, the logger would have to detect this (perhaps if it gets failed pings to the Scada host) and then switch to sending data via the 3G modem to the same port on the SCADA host which is acting as a Modbus slave. Thinking about this further, if the logger was always sending the data (as a master) then the SCADA system might not notice the change of route, so there may not be a data stiching issue.
In both cases the time delays (Loggernet and Modbus) the time to get real data depends mainly on how often the logger is programmed to calls back to Loggernet / the Scada system. This could be set to happen every few seconds in needed.
The delay for the changeover depends on how sensitive you want to make detection of the failed connection. If using PingIP you might for instance want to check 3 or 4 times a second or so apart for a reply before deciding the connection is down as pings can get lost sometimes. On failure you then could set a flag to tell the next transmission to be send via the backup route.
If you are running a modern SCADA software package, they generally have a SQL database link. Loggernet has an available LNDB addon that can be purchased. With LNDB, the data is pushed by Loggernet into an LNDB database and the SCADA software can directly pull from the database.
It is worth looking into.
Yes. The aps's answer is realy clear. JDavis's reply is the good idea, we'll note this as one solutions which we can chose.
Thank so much for your support!