messages 01 to 04).įurther the address of the variable in the station is entered in the Data-sent in the Addr variable.
MODBUS MACRO TO SEND FROM MODBUS SERVER DRIVER
The driver sends these messages but does not wait for response - therefore it is not relevant to set address 0 for messages that are to read (e.g. for the messages received by all stations (if the Modbus protocol is used on higher network level, then the broadcast may not be allowed). The address 0 is used for the broadcast, i.e. for the Modicon, valid Slave addresses are in the range of 0-247). This address is entered on the " Data-sent" tab of the message in the Slave variable (e.g. The address of the Slave station from which it is read or to which it is written, must be entered in each message. For example by the "XX-User defined opened function" type message it is possible to compose any Modbus message types, that are not directly supported by the driver. The communication description by means of the PmaCommMsg objectThe PmaCommMsg object can be used for special communications, that cannot be executed by the PmaCommGroup object. Increasing these values (if the device allows it) may cause higher communication speeds because the transmitted data can be sent in a lower number of communication messages. The preset values are 64 for Bo and Bi, 32 for Ro and Ri (if the preconfiguration for a specific device is not used - see Preconfigurations / Communication / Modbus).
These values depend on the device type to communicate with (some devices support transmissions of low register numbers in a single message, other support higher numbers) - this specification can be found in the device documentation or must be tried/tested. Maximum number of variables received in one messageįor each area ( Bo,Bi,Ro,Ri) the maximum number of variables to be transmitted in one communication message is defined here.
While communicating, the "Data item address" is modified as a sum of the relative item address (defined in the ItemID identificator) and the area base address. the addresses do not begin with 0, but with 1 or 40001, etc.). For another PLC types the addresses my be different (e.g. (if the preconfiguration for a specific device is not used - see Preconfigurations / Communication / Modbus). The addresses for these areas are preset to 0. Here, the addresses of the beginnings of the data areas are entered ( Bo, Bi, Ro, Ri). This parameter can be modified and read in the script during runtime by methods: SetSpecParam ("SlaveAddr") and GetSpecParam ("SlaveAddr"). the "D" character means default, (it means that the address is taken from this configurator). The ItemId identifier may look like for example " ", where: Macro expression can be used for input (it is evaluated after starting the application). The text can be written manually, or it can be assembled in the window opened by the button to the right of the configurator.
MODBUS MACRO TO SEND FROM MODBUS SERVER HOW TO
The " ItemID" configurator tells the driver how to receive or send the item value. ItemId is the text identifier of the item that is used for addressing the item in the device. When writing into the variable, only the single variable is sent (if the " Auto send when writing to item" configurator is checked).ĭescription of the " ItemID" configurator: The driver uses optimalised internal communication messages for reading the data from the device.Īll variables are read (if the " Data refresh enabled" configurator is checked). The variables in the PmaCommGroup object (or even better the variables in the PmaData object with ExtComm data extension) can be of arbitrary number, type and order. For usual data transmissions it is more favourable than using the PmaCommMsg object. The communication description by means of the PmaCommGroup objectThe PmaCommGroup objects can be used for this driver.
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