Precision Digital PD6730X - Manual (Page 39)

PD6730X Vantageview Super Snooper Modbus Scanner Instruction Manual
39
Response Timeout (TIMEOUT)
Enter the time the scanner will wait after a request for information has been sent to a slave device before
it will assume an error on that request. Increasing the timeout will help eliminate polling errors when
polling slow devices. Increasing the response timeout will also slow the PV update rate in systems that
are experiencing communications failures.
Note: The feet and inches display models enter this value in the format XX.X seconds, but no decimal
point is present in the display. For example: enter 20 for a poll time of 2.0 seconds.
Retries Before Error (RETRIES)
Enter the number of consecutive failures to poll a device that will result in a communications error
message on the display. This is the number of times a specific PV must be polled before the display
indicates a communication failure rather than displaying the available PV data. Increasing this number will
allow for more polling failures before a communication error is detected, which may be required for some
unreliable networks. Increasing this number will also increase how long old data is displayed before a
communication error is indicated.
Slave Mode (SLAVE)
In Slave mode, a Modbus master may write up to 16 Modbus PVs to the scanner, which can then display
and process the data in the PV Modbus registers, such as displaying the data and using them in math
functions.
Programming the scanner for Modbus Slave mode will include defining the Modbus PV registers that are
enabled, as well as selecting the time between data writes before an error is assumed. In Slave mode the
scanner accepts floating point data (Byte order: 1234 big endian).