Ritron DATAFLOW RTU Series Guía de usuario descargar pdf (Pagina 49)

Software/Programming

EXAMPLE 7

8.8 EXAMPLE 7 demonstrates the DATAFLOW RTU as a MODBUS device using stored data

access. The configuration consists of a remote RTU with another RTU connected to a MODBUS

controller. Example 7 uses RTU Programming Software as the MODBUS controller. The remote

RTU and the RTU connected to the MODBUS controller each have five digital inputs and one

analog input.

NOTE: In real applications the MODBUS controller is a PLC or a SCADA program operating

with a MODBUS driver.

8.8.1 RTU ID 1 SETUP: Example 7 requires one DATAFLOW RTU to be wired and its hard-ware

configured according to Figure B12 - EXAMPLE 6 ID 1 Wiring Diagram on page B-36. Load

Software Programming configuration file EXP7ID1.USR into RTU ID 1.

8.8.2 RTU ID 2 SETUP: Example 7 requires the other DATAFLOW RTU to be wired and its

hardware configured according to Figure B13 - EXAMPLE 6 ID 2 Wiring Diagram on page

B-37. Load Software Programming configuration file EXP7ID2.USR into RTU ID 2.

NOTE: Except the configuration files, these two setups are identical to Example 6.

8.8.3 EXPLANATION: Although the RTU can operate in two different MODBUS modes, Example 7

deals with stored access only. In this mode, only the RTU connected to the MODBUS controller

is polled, eliminating the need for RF polling.

8.8.4 Examine the configuration of RTU ID 1. It is no longer in control of the process and is simply a

ODBUS device controlled by the MODBUS controller:

· XMIT CHECK IN is set to 0.

· SEND LIST is all 0s.

· REPEAT LIST is all 0s.

· All inputs have INITIATE XMIT set to NO.

· All outputs have USED set to NO.

Examine the configuration of RTU ID 2. It controls activation of RTU ID 1.

· XMIT CHECK IN is set to 30 seconds.

· SEND LIST is set to 1.

· REPEAT LIST is all 0s.

· All inputs have INITIATE XMIT set to YES.

· All outputs have USED set to NO.

NOTE: Examine the SCADA CONFIG screen display for RTU ID 1. All entries in the list are 0

because no RF polling is taking place.

8.8.5 Example 7 demonstrates polling by stored access, using the RTU Programming Software as

the MODBUS controller. To examine the polling method, execute the EXTERNAL BLOCK EDIT

option from the UTILITIES screen.

· Set the ID to 01 and the PAGE ADDRESS to 10. Execute the UPLOAD command.

Examine memory locations 1089 to 108E. These values are the current state of RTU

ID 2 inputs 6 to 1.

· Memory location 108F is a message counter. This value is incremented every time RTU

ID 1 receives a valid message from RTU ID 2.

Change the inputs on RTU ID 2 while continuously executing the UPLOAD command. Watch the 1089

to 108F memory locations update each time.

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