3. Technical specificationsProduct description
Festo.P.BE-CMMS-ST-HW-EN 0903b
35
Control via RS-485
Note
Before activating the RS-485 interface, please make sure that you
are using a completely wired null modem cable. All pins of the
cable must be occupied according to the following specification.
Pin Brief
design.
Designation
Signal direction
Description
1
DCD
Data carrier detect
Transfer device -->
end device
Data carrier signal was recorded by
transfer device
2
RxD
Receive (x) Data
Transfer device -->
end device
Line at the end device that receives a
data bit from the transfer device.
3
TxD
Transmit (x) Data
End device -->
Transfer device
Line at the end device that sends a data
bit to the transfer device.
4
DTR
Data terminal ready
End device -->
Transfer device
End device is ready for use
5
GND
Ground (earth)
None
Reference potential at 0 V
6
DSR
Data set ready
Transfer device -->
end device
Transfer device is ready for use
7
RTS
Request to send
End device -->
Transfer device
End device displays that the remote
station should send (send request)
8
CTS
Clear to send
Transfer device -->
end device
Transfer device shows reception
readiness (send permission)
9
RI
Ring indicator
Transfer device -->
end device
Transfer device receives a ring – or call
sign on the telephone line
Tab. 3.13: Design of a null modem line
Configuration in the FCT
For configuration, the following settings are required in the "Work station" window:
-
On the "Application data" page in the "Operating modes settings" tab, set the control
interface to "RS-485".
