B&B Electronics RS-485 manual Set Turn-around Delay, Command$ = ! + CHR$addr + SC + CHR$delay

‘Clear bit 2 of states to make digital output 2 LOW states = states AND (NOT(4))

Command$ = “!” + CHR$(addr) + “SS” + CHR$(states) Print #1, Command$

At power-up digital output 0 will be HIGH, digital output 1 will be HIGH, and digital output 2 will be LOW.

Set Turn-around Delay

The Set Turn-around Delay command sets the amount of time the 485SDA10 waits to respond after executing a command. This delay is necessary when two RS-485 transmitters are sharing a pair of wires to ensure that two transmitters are not enabled at the same time. Refer to B&B Electronics’ free RS-422/RS-485 Application Note for more information on RS-422/485. The turn-around delay is stored in non-volatile memory. This command requires a data byte. The data byte is used to specify the turn-around delay. One unit of turn-around delay is equal to the transmission time of one character. This transmission time can be computed as follows:

time = (1 / baud rate) * 10

The steps to setting a module’s turn-around delay are given below:

1)Constructing the command string:

Command$ = “!” + CHR$(addr) + “SC” + CHR$(delay)

Where addr is the module’s address and delay is the turn- around delay. Refer to Chapter 3 for more information on turn-around delay.

2)Transmitting the command string:

Print #1, Command$

Example 5.6 – Set the turn-around delay on the module with address 5 to 100 character transmission times.

addr = 5 delay = 100

Command$ = “!” + CHR$(addr) + “SC” + CHR$(delay) Print #1, Command$

The module at address 5 will now have a turn-around delay of 100 character transmission times.

485SDA103798 Manual 27

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