Modbus RTU

note if multiple stations are connected to the rs 485 bus, then use the docid\ vo594n1omayqaztcnfxr driver instead of this one review the following information for setting up and configuring the modbus rtu driver litmus edge compatible series compatibility parameter compatible items driver type serial (rs 485) when to use serial connection to a device using modbus rtu replaces gen 1 driver(s) docid\ ufdsdcj0htv8fkv2ybetm docid\ lruq4f sopiyuhzdmguw3 learn more about docid 9115fvefze7bso1p2ltd to set up and configure this device in litmus edge, you will need to do the following step 1 set up and configure the plc device step 2 set up the plc device in litmus edge devicehub step 3 configure the list of registers step 1 set up and configure the plc device record the serial communication parameters for the device otherwise, use plc software on your machine to look up these parameters you use these parameters for setting up the driver in the next step step 2 set up the plc device in litmus edge devicehub configure the following parameters when you docid\ pal6abpzbrimdu9lvgj30 with this driver update default values to the specific setup of your device parameter value type modbus driver modbus ascii device file the file of the serial port you are using baud rate 19200 data bits 8 parity select even, none, or odd station id 0 stop bits 1 zero based addressing select enable or disable step 3 configure the list of registers when you docid 8se7z3pmrfwl1nmzcwalx to the connected device, refer to the following register table and tag parameters refer to the following additional resources docid 583p fbuozem6whgrdgkq docid\ ifbwcou90qtfodk hrysr register table note the address format in this gen 2 driver is different from the gen 1 driver ( docid\ ufdsdcj0htv8fkv2ybetm ) for the same device learn more about docid 9115fvefze7bso1p2ltd name value types address format min address max address description d bit ddddd 0 65535 discrete input contacts c bit ddddd 0 65535 discrete output coils h word, int16, int32, uint32, float32, float64 ddddd 0 65535 analog output holding registers i word, int16, int32, uint32, float32, float64 ddddd 0 65535 analog input registers h bit bit ddddddd 0 6553515 analog output holding registers i bit bit ddddddd 0 6553515 analog input registers tag parameters name select a register name from the drop down list the available options depend on the names in the register table value type select a data type from the drop down list the available options depend on the register name selected polling interval enter a value in seconds this determines how often the tag should poll the register for data tag name enter a name for the tag description (optional) enter a description for the tag address enter a tag address the value must in the decimal format, within the allowed min/max range omit the leading zeros the device might use the decimal (d), hexadecimal (h), or octal (o) address format see the register table at the bottom of the dialog box for bit tags, append the bit address without the bit separator the lowercase letters in the address format indicate how many digits you should enter in the bit address count enter the number of register values to read a count higher than 1 will generate an array of values from the address value configured and respective subsequent address values endianness (not available for all names) this option configures how the tag data will be formatted and whether bytes and/or words will be counted from the start (big endian style) or end (little endian style) of strings of data select one of the following options no swap data will be formatted in big endian style (bytes and words counted from the start) for example ab cd swap bytes only bytes will be formatted in little endian style (counted from the end) for example ba dc swap words only words will be formatted in little endian style (counted from the end) for example cd ab swap words & bytes both words and bytes will be formatted in little endian style (counted from the end) for example dc ba tag formula enter a formula for the tag to process the generated data two variables are permitted value (current tag value) and timestamp (current tag unix time in milliseconds) the following math functions are available sin cos sqrt tan power power( x ) performs the operation 10^x log log( x ) is the natural logarithm (the logarithm is in base e ) exp exp( x ) performs the operation e^x only publish on change of value select the checkbox to customize nats messages to be published only when the value parameter changes from a previous value to a new one change of value only applies to boolean, numeric (such as int or float), and simple string data types it does not apply to complex types, such as json or array poll once topics will not be affected by change of value settings these topics will still only see a single message meta data metadata summarizes basic information about data this feature allows you to define key value pair data for the device output payload later on it can then be used to find, use, and reuse particular instances of data note if you use special characters in meta data key names, the special characters are replaced with underscore characters in the payload this can cause two key names to be combined into one for example, configuring the key names a b and a&\&b will cause only one key name to be created (a b)