Magic 485F Adapter
Page
7
2.5 Transmitter Turnaround Delay
By the nature of the operation of the unit there will be a time delay in the switching of the unit from
transmit to receive. This time can be fine tuned to the particular installation and the length of the cable
run, resulting in quicker operation. This operation can only be tested on a trial basis and is
accomplished by the setting of SW1 Bits 1-3 on the 485F25 as described in Table 2.1, and cutting or
resoldering the tracks between the pads of J2 on the 485F9 as shown in
Figure 2.3.
1
2
3
4
Function
X
X
X
ON
RS485 termination on, termination resistor fitted
X
X
X
OFF
RS485 termination off, termination resistor not fitted
OFF
OFF
OFF
X
RS485 transmitter turnaround time = 4 us.
ON
OFF
OFF
X
RS485 transmitter turnaround time = 8 us.
OFF
ON
OFF
X
RS485 transmitter turnaround time = 16 us.
ON
ON
OFF
X
RS485 transmitter turnaround time = 32 us.
OFF
OFF
ON
X
RS485 transmitter turnaround time = 64 us.
ON
OFF
ON
X
RS485 transmitter turnaround time = 128 us.
OFF
ON
ON
X
RS485 transmitter turnaround time = 256 us.
ON
ON
ON
X
RS485 transmitter turnaround time = 512 us. (
default
)
TABLE 2.1
485F25 BIT SWITCH SETTINGS AND FUNCTION
FIGURE 2.3
485F9 LINK SETTINGS AND FUNCTION
RS485 transmitter
turnaround time = 4us
RS485 transmitter
Turnaround time = 8us
RS485 transmitter
Turnaround time = 16us
RS485 transmitter
Turnaround time = 32us
RS485 transmitter
turnaround time = 64us
RS485 transmitter
Turnaround time = 128us
RS485 transmitter
Turnaround time = 256us
RS485 transmitter
Turnaround time = 512us
(default)
R4
R3
R2
Position of links on 485F9
