176
Remote Terminals
Section 5-1
Communications Mode Settings (SRT2 Series Only)
The communications mode is set with pin 3, as shown below.
The communications mode settings using pin 3 only apply to the SRT2-series
Slaves and cannot be used with the SRT1-series Slaves, which operate in
High-speed Communications Mode at all times.
Hold/Clear Outputs for Communications Error
Pin 4 is used to set the output data status when a communications error
occurs, as shown in the following table.
Internal Circuits
The following diagram shows the internal circuits for the SRT
@
-OD16T.
The following diagram shows the internal circuits for the SRT
@
-OD16T-1.
Pin 3
Communica-
tions mode
Communica-
tions distance
Communica-
tions baud rate
Communica-
tions cycle time
OFF
High-speed Com-
munications
Mode
100 m max.
750 kbps
0.5 or 0.8 ms
ON
Long-distance
Communications
Mode
500 m max.
93.75 kbps
4.0 or 6.0 ms
Pin 4 (HOLD)
Setting
OFF
Clear output
ON
Hold output
DC static
converter
(Insulated)
Inter
nal
circuitr
y
Photo-
coupler
Photo-
coupler
ST
ST
ST: Step-down transformer
24 V DC
24 V DC
0 to 7
8 to 15
DC static
converter
(Insulated)
Inter
nal
circuitr
y
Photocoupler
Photocoupler
ST
ST
ST: Step-down transformer
24 V DC
24 V DC
0 to 7
8 to 15