General Explanation: Data Recorder can connect more than one PLCs via distinct serial ports and MPI adapters. No limitation for connection number. Connected PLC's tag values reads and writes at the same time without certain order. Thus increase in the number of PLC's does not effects speed of reading data. Other advantage is that you don't need to connect PLCs to the same network in order to reach all PLCs with single scada.
Connect: You can activate only this network.
Disconnect: You can stop only this network. If all networks activated via Data Recorder connect button Data Recorder restarts this network automaticaly too.
StatusStrip: Information group at the ActiveX subsection. The first data in this group is Tag count. Then "Good" successful communication count. "Bad" is the failed communication count.
Query Byte Count: Most important information for this section. According to entered variable address informations ActiveX automaticaly calculates Modbus Rtu query and sends to the PLC. Here according to result of the query you can see the byte count that PLC should send. High number means less packet count. Packet number is more important than packet size for the Modbus Rtu protocol. To improve performance it is necessary to keep down the number of packages.
Error: Here you can see error messages from the PLC.
Rtu Network Menu: Modbus Rtu Network is the first element of this treeview menu. Second element is station, last element is the group. When element selected tag list at the right filled with that element's tags.
Rtu Network: You can see PC port settings and Rtu .NET settings here. When you right click on this area the operation menu opens. Most important parameter of MPI network settings is the pool.interval parameter. By this parameter you can set the period of the queries that sent to the PLC. This has no effect when data written to the PLC. When write command taken data transfers to the PLC without delay.
Station: You should enter station information here.
Adress: Here you should enter PLC modbus address. Each station address must be different from another.
File Repeated Queries: Enter here query repeat number for communication error.
Function Code 6 Enable-Disable: Some PLCs do not use function code 6 at data writing operation. Instead, they use function code 16 which fulfills the same task.
Discrate Max. Block Size: At Modbus protocol 8 to 2000 bits can be read at once. But at some PLCs this package can be smaller. Set maximum package size with this parameter.
Analog Max. Block Size: At Modbus protocol 1 to 125 registers can be read at once. But at some PLCs this package can be smaller. Set maximum package size with this parameter.
Group: One of the most important matters in ActiveX.All serial communication methods have limited capacity. Different groups can be created in order to use this capacity with best way. With groups "cycle" parameter some groups can be read at every cycle some groups can be read less frequently. Thus some PLC values can be read fast some values can be read slow. Applicable number of groups is 128. Other benefit of the groups is the asists arranging query byte number which will detaily explained later. Moreover, it is useful in tracking the data when communicating a lot of data.
Tag List: Table for creating a new tag, monitoring tag's values and writing new values. Group must be selected at the left side in order to make operation on this table. If group is not selected only set value can be write. When group selected only the tags that belong to that group are listed. When station or network selected all relevant tags are listed.
Adress: You should enter this column the Tag's address in the PLC. You can enter HEX value here. All you need to do is adding "h" beginning of the value.
Tag Name: System gives the unused name to added tag. You can change it later then. All tag names must be unique.
Value Type: Shown number types: Boolean, Usigned int16, Signed int16, Bcd, Usigned int32, Signed int32, Floatpoint, Long Bcd, Time Of Day, Date. We think that some number types should be explained. Floatpoint type also known as single. Date type is the day number that named as word. Beginning of date is "1.1.1990".
Read Value: The values that read from PLC shown at this column.
Write Value: The value written on this column is checked if has error first. If it has not error sent to the PLC. Data input process to the PLC is a priority. As soon as after the active query completed write operation activated without waiting other operations.
To obtain the best performance issues must be considered: ActiveX tries to read all tags within the same group once. Calculates the query that will be sent according to the address data entered to the Tag list. If entered adress are consecutive reads all list at once.Number of bytes to be read at one time is limited to 250. ActiveX reports calculated query size with "Query byte count" which resides Statusstrip. If you see different number than your calculated query size probably you made a mistake.
Let's explain the subject with a couple example. Some query examples and total byte sizes are given below.