I have a waste treatment system that uses a Horner PLC with a built in HMI on it. It also has an Ethernet to Cellphone interface that connects the PLC to the Internet at all times. This connection is used for several things:
1st to allow debugging and program updates remotely.
2nd To allow a proprietary Horner program to display and operate the HMI just as if you were there.
3rd The PLC sends out emails with several functions. It sends data files for data collection. It also sends emails to inform the technicians and the engineers that there is a fault. Along with the fault email it attaches a .csv file so the technician and engineers can know what the fault is.
Our problem is that since the IPhones that the company uses were updated with IOS 7, the .csv files don't come through the IPhone properly and won't display right.
So I am going to set up this program on their IPhones and hope that the PLC can communicate with several IPhones at the same time. Since I know that they will all jump and grab their IPhones anytime they have a fault email. So can this program on several IPhones access the same PLC at the same time?
Each PLC can communicate with several iPhones at the same time. How many depends on the available TCP sockets in the PLC. This can be anywhere between 16 and 64 -or more- depending on brand and PLC model. I am not sure about Horner PLCs, but you should be able to find this information from your local dealer or PLC manufacturer. You must ask for "Available TCP Sockets", or "Simultaneous TCP Connections" or something to that effect. I hope this helps. The ScadaMobile or Modbus Gem apps do not have any limitation on this regard.