Communication driver configuration PmModbusMr - Driver for communication by the Modbus Master protocol
The West ProVU4
device is designed for temperature measurement and regulation. The PROMOTIC application communicates with the device by means of the PmModbusMr
communication driver via the RS485
serial bus via the computer's serial port, but it can also have a TCP Ethernet connectivity.
See also Communication with meters and regulators by the West Instruments company
The device can be connected to the PC using the RS485/RS232
converter via the computer's serial port (RS232
). The connection is described in the manual supplied by the manufacturer of the device.
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 communication protocol"
This preconfiguration can be created in the object: PmaFolder
- 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 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 stated in the description of the manufacturer protocol.
object named "Trend
" contains the setting in the "Storage type
" configurator, that defines saving the trend values into Database dBase backups
. The variables for the PmaTrendGroup
object are defined in the PmaData
object using the ExtTrend
If it is necessary to have the read/write value with the precision of one decimal digit, then it is possible to read/write the value from the address according to the following formula (in decimal): base address + 16384
and then multiply the value by constant 0.1
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 the OS Windows (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.
|Default PLC address||Valid device address within the MODBUS network. See:Default PLC address|
|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.