Watts LF007 Serie Instrucciones De Instalación página 20

Test Communication
After the utility software serial port has been configured, check for valid communication
between the computer and the module. Valid communication with the module is required
before the configuration process can start. To test the communication, set the Modbus
Address to 01 in Default Mode or set the Modbus Address to match the setting in the module.
Set the Function selector to 03 and the Register selector to 40001. Click Send to verify
communications. A data value is displayed in the Response field.
The preceding dialog box illustrates the Modbus function 03 being sent to Modbus slave
address 01. Both the command and response messages are displayed beginning with CMD
and RSP, respectively. This display format is provided for troubleshooting purposes as it displays
each byte of information being sent to and received from the module. This format can be a trou-
bleshooting tool or a way to become familiar with the formatting of the Modbus RTU protocol.
The response data value from register 40001 is located in the RSP: line. The data value
returned is a 16-bit value located in the fourth and fifth bytes in the message (00 01). The "00 01"
indicates that the register value is 0001. From the Input Register Assignments map, register
40001 contains the Modbus slave address value. In this case, the module slave address value
is read back as 0001.
In the event that the module is not detected by the software, then the RSP: line reports "RSP:
Timeout – No Response Detected!" Several things can contribute to this problem; for example,
no power to the module, bad RS-485 wiring connection(s), invalid port settings, or RS-485
half-duplex handshaking problems. All can cause timeout errors. Timeout errors must be
corrected before attempting to configure the module.
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