iRemote - application
iRemote - Konfiguration
iRemote
Introduction
The Apple iPhone comes up with a compact and smart platform including a huge amount of possibilities for individual applications for business usage as well as for private purposes. These applications can interact with all the extensive functions of the device to offer the user an interactive touch-controlled interface, which enables a variety of different forms of communication.
Radio-transmission devices for data utilisation developed by the company Funk-Electronic Piciorgros GmbH have been extended by ethernet functionality. The following described software enables the user to control a radio-transmission-unit (RTU-710E) while switching targeted binary outputs.
The applied protocol is called modbus over IP. The target device can be characterized as a pair of IP-address and portnumber. The targeted outputs can be accessed via a freely adjustable modbus command.
The executed sending operation is conveyed to the user as an acoustical signal, a short vibration tells the correct reception of the answer from the target device.
User interface
The application iRemote contains two interfaces the user can interact with. The first one can be seen on the right side. It is the executable interface which puts the user in a position to send out up to ten individual commands. The view is based on the look-and-feel of the radio handset that provides comparable functionality using radio transmission.
The keypad shows the keys zero to nine and two additional keys with special functions. Thus the key labelled C leads to the configuration view of the application. This will be described in the next chapter.
Pressing the key labelled with E stops the execution of the program and switches back to the home-screen of the iPhone like its own home button.
Putting pressure on a numeric key effects the execution of a transmission operation. As soon as the touch of a key has been registered, the user is informed by an acoustic signal. Following a connection to the target device (RTU) is initiated and the command is send.
Afterwards the application waits for a response from the remote RTU. Having received the answer it is proved to be correct. If this test is passed successfully, the user feels a short vibration as affirmation.
In the case of a failure checking result or if no response could be received, the device does not vibrate and after a time of 15 seconds the keypad is released again and a relating error message is immediately shown. Thus the application is ready for the next execution command.
While starting iRemote it can not be assumed that the iPhone provides a valid connection to a network. This is done by the policy of acting energy-efficient. This situation is detected and the application has the additional task to build up the connection. This can be realised as a longer delay time. Executing the next operations can than be done much faster. Normally the time between the acoustic and the vibrating signal takes less than one second.
The letters that can be seen on the numeric labelled keys have no relevance for the execution and can be ignored.
Configuration
The concept of this application iRemote includes the individual and independent configuration for each of the ten numeric keys in the main interface. The configuration view is reachable by pressing the key labelled C. the keypad view is then flipped and changed into the configuration view which can be seen beside.
On top of the view the user can first select the key he wants to configure with his next steps. In the example the key labelled 3 is selected.
Following the target IP-address and the corresponding portnumber of the controlled RTU can be edited. Dependant on the configuration of the router connected to the RTU it is possible to reach several RTUs with the same IP-address. They just have to have varying port-dependencies by which they can be selected.
The content field includes the modbus command that is meant to be send. The protocol is described in the next chapter. The field can contain any data for sending, but for the main functionality of the application it is important that the data is modbus-conform and the switch underneath is true.
Further more it is essential that the transport protocol is selected as TCP. Alternatively UDP as a connectionless communication can be selected. But this option is currently not supported by Piciorgros devices.
The content of the fields is changed as soon as another keynumber is selected in the upper bar. In the background this action effects that the current values are stored in a database as parameters for the current key. From the same database the new contents are read and displayed in the view. This means that the parameters are saved with each selection of a new keynumber. The same happens when the user touches the Done-Button in the upper right corner to get back to the main control keypad view.
Modbus over IP
The modbus over IP protocol is a way of transmitting information where a TCP/IP-package containing a modbus command is used.
A modbus command is structured with leading header information to notify the target device how to handle the following payload. After that, the pure modbus command as it is used for serialised radio communication, is appended. This consists of the type of remote action, the amount of affected registers and the raw data used for executing the command. The normal behaviour of appending a crc-checksum is omitted because the TCP frame itself ensures an assured transmission.
The following table describes the meaning of bytes from the modbus command. This data represents the content of the according text field.
| bytes | example | description |
| 1,2 | 10 | write-command |
| 3-6 | 012C | starting register for writing action (fixed address for binary outputs of the target RTU) |
| 7-10 | 0001 | command to write one register |
| 11,12 | 02 | command to write two bytes (verification for bytes 7-10) |
| 13-16 | 0004 | new content for the register |
The remote RTU is effected that the value 04 [hex] is written to register 012C [hex] (which equals 300 [dec]). The outputs are switched like 0000 0100. that means seven outputs are switched to zero while the third one is gets the logic value one.
Implementations
The application is a licensed product for the usage on an Apple iPhone or iPod Touch. Both devices are equipped with a 320 x 480 pixels touch screen display and the possibility to connect to the internet via WLAN or if it is an iPhone also via GPRS and EDGE.
Thus the application is as far as possible independent from the location. The target device can be connected to the internet everywhere in the world, too. The applications communication with the device can either happen in the internal network or completely detached from this.
The switched outputs can be analysed specifically for the attached implementation and used as input for connected systems like pumps or visualisations.
Possible expansions
At the moment the prior supported protocol is modbus over TCP. The application enables the user to control devices developed by the company Funk-Electronic Piciorgros GmbH. In future it could be possible that this communication is also enabled with the UDP protocol.
For special implementations it might be possible to adjust the keypad view. Thus e.g. the geographical location of the controlled RTUs in the network could be shown as a picture. The positions of the keys could be adjusted to the graphic.
