Communication by the Modbus RTU
protocol with AMiT
IO modules of the DMM
series.. See Communication with the IO modules by the AMiT company
This preconfiguration can be activated when creating a new object (e.g. by "New object ..."
in the local object menu or after pressing the Insert
key after selecting the object) and is included in the group: "/ Communication / Modbus"
This preconfiguration can be created in the object: PmaFolder
The preconfiguration creates an object of the PmaComm
type and data for the corresponding number of analog and digital inputs and outputs. Also the panel with complex Pmg
objects is created for displaying their status. This allows to define the required number for the specific connected device.
The preconfiguration is created for serial link Modbus RTU
. The modules use the RS485
bus for communication. It is important to ensure that additional communication parameters are correctly configured (device address, port number, transfer rate, parity, ...) The configuration procedure of the devices is described in the documentation provided by the manufacturer. The communication parameters in the PROMOTIC application are defined in Setting the parameters of the serial link
of the PmaComm
object and in Parameters
of the PmaCommGroup
- The preconfiguration is created including the panel (object of the PmaPanel
type) is functional also a Web panel
- The panel is used for communication testing and it is not essential for the communication functionality.
In the PmaComm
object named "Comm
" the communication parameters are set (Serial port
, Baud rate
object named "data
" includes a "Parameters
" tab where Special Parameters
are defined (see PmModbusMr - Driver for communication by the Modbus Master protocol
). On the "Data
" tab, the items are imported by data extension of items defined in the PmaData
object (see ExtComm
). Each Data
corresponds to the selected device type by its structure and name.
Some types of the I/O modules (DMM-DI24
) allow to use any of the binary inputs as counters. In this mode it is possible to read the walues but also write (reset the counter). Detailed specifications and limitations is described in the documentation supplied by the manufacturer.
This preconfiguration is not designed for modules of the DMM-FCx
type. These devices allow only reading/writing to the specific addresses in the Modbus communication that has specific meaning.
These configurators can be set before the preconfiguration is created:
|The name of created object||Name of the object created in the tree of Pma objects. The maximum name length is 30 characters. This is a system name, so it must contain only alphanumeric and must not contain any diacritics, empty string, spaces and the first character must not be a number.
|Serial port||Selection of the communication serial port.
The value can be change by the OpenPort method.
The value can be detected by method GetProtParam("SerPort").
After the preconfiguration is created, the "PmaComm > Setting the parameters of the serial link > Serial port" configurator will be set to this value.
- The object is not connected to any port after starting the application and the serial port can be selected dynamically by the algorithm (by the PmaComm.OpenPort
COM1, COM2,..,COM66 - The specified serial port is opened after starting the application. This port must be correctly configured and accessible in Windows OS (no one can use it).
For serial link each PmaComm object must have defined another communication port. For example, if one PmaComm object communicates through COM1, then next PmaComm object can communicate for example through COM2 (COM3, ...) but it mustn't communicate through COM1.
|Baud rate||Selection of the baud rate (bps, bit per second).
This configurator sets the initial value of the BaudRate property.
After the preconfiguration is created, the "PmaComm > Setting the parameters of the serial link > Baud rate" configurator will be set to this value.
|I/O module address||Valid device address within the MODBUS network.
After the preconfiguration is created, the "PmaCommGroup > Parameters > Special Parameters > Default PLC address" configurator will be set to this value.
|Communication refresh rate [ms]||The period in milliseconds to be used for reading the current data by the PROMOTIC application.
After the preconfiguration is created, the "PmaCommGroup > Parameters > Communication refresh rate [ms]" configurator will be set to this value.
|Number of analog inputs||Allows to enter the number according to the device type|
|Number of digital inputs||Allows to enter the number according to the device type|
|Number of digital inputs used as counters||Allows to enter the number according to the device type|
|Number of digital outputs||Allows to enter the number according to the device type|