Sealevel Modbus Connect iOS App

Sealevel Modbus Connect iOS App


Hi, I’m Will Rostron I’m a tech support engineer with Sealevel Systems Today I’m going to demonstrate our new iOS app Modbus Connect The app communicates with our Modbus TCP devices over Wifi Modbus is an open communications protocol that originated in 1979 Modbus is widely supported and used throughout the world In industrial automation Data acquisition And test and measurement applications Sealevel’s Modbus Connect app Aids developers using Sealevel Modbus devices With application development Testing and troubleshooting With Modbus Connect you will be able to read and write directly to the I/O And see the actual data transmitted Modbus Connect is a universal app That runs on iPad iPhone and iPod touch platforms Running iOS version 7 or later. We will start the demo and launch the app By tapping the Modbus Connect icon There are six screens and the app starts in Settings This lets you set up the app to connect with the I/O device You can swipe to go to the next screen Or you can select the screen in the tab bar The Test Screen lets you connect to the Sealevel device and run common Modbus functions The My Device screen will show you the Modbus data type for each I/O bank The Raw Frames screen shows you the data in the most recent Modbus transaction The User Request screen lets you send customized Modbus commands The About screen provides our contact information Now let’s look at the Settings screen in more detail The app starts up with the default IP address for Sealevel eI/O modules On this screen you can set the IP address of the device Notice that multiple IP addresses are remembered during this session You can ping the device to make sure that you can reach it The default Modbus TCP listen port is 502 But it can be changed for devices on remote networks Or behind a firewall The connection timeout default is 2 seconds That’s excellent for most purposes You can change it from 1 second to 20 seconds For unusual circumstances You normally won’t change the receive timeout or the floating point format But the options are there if you need them The iOS device’s IP address is shown at the bottom But an error will appear if the Wifi connection isn’t active Next, we will look at the Test Screen On this screen you can connect to the IP address Of the module you configured on the previous screen If you have a SeaI/O module You should configure the Unit ID before you connect In the Access type, you can select the Modbus data type that you are using Modbus coils correspond to Reed relays, Form C relays and open-collector outputs Modbus discrete inputs correspond to Optically isolated inputs and dry contact inputs Modbus input registers correspond to analog inputs Modbus holding registers correspond to analog outputs Let’s connect to the device at ID 247 The connection state is shown in an icon At the top left of the screen The My Device screen shows you the Modbus I/O map for the device that you are connected to This is a SeaI/O 570 It has eight Modbus discrete inputs Eight coils and eight input registers Each of these start at address zero Once we know the Modbus types and address ranges We are ready to work with the device Since the SeaI/O 570 has eight coils Let’s change the number of coils to eight When we read the coils, we can see that the first three are set We can change the state of one of the coils And when we write to the device, the relay moves The first discrete input is connected to the first coil We can see this when we read the eight discrete inputs The repeat last read/write slider is used to automatically read the discrete inputs When the slider is all the way to the left, which is off You have to manually read the inputs As we move the slider to the right from slow To medium And fast, the message count rate changes accordingly As we move it back to the left You can see that the message count slows down When the slider is off We have to read the inputs manually The reset counts button Resets the message and error counts The Raw Frames screen shows you the Modbus data as it appears in the TCP packet The Request is from Modbus Connect to the I/O device The Response shows you the TCP packet from the I/O device back to Modbus Connect The User Request screen lets us send custom Modbus commands Let’s write all eight coils and turn them On That’s function code 15 We’ll need to tell it that we’re setting eight coils And there is one byte following FF sets all eight coils On The response 00 says that there are no errors And we end on the About screen This concludes the iPad portion of our demonstration Sealevel Modbus Connect has the same functionality on the iPhone and iPod touch You can select your device’s IP address You can ping the device Notice that the host IP address is still displayed On the Test screen you can connect to the device Read the device Even change the repeat rate And the message count follows accordingly The My Device screen shows you your Modbus map And Raw Frames shows you the raw TCP data going across the connection On the More tab, it allows you to access additional screens And you can change the position of the screens with the Edit button The User Request screen allows you to send custom Modbus functions And you can go to the About screen With Sealevel’s contact information This concludes our demonstration of Sealevel Modbus Connect

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