Interfaces; Connection Of Several Load Cells To A Pc Via Rs-485 - HBM FIT7A Bedienungsanleitung

Interfaces

6 Interfaces
The load cell can be provided with an RS‐485 interface, a CANopen interface,
or a DeviceNet interface, as required. The reference potential of all the
interface signals is GND (supply ground) of device socket 1.
6.1

Connection of several load cells to a PC via RS-485

Line termination
+5 V
500 Ω
500 Ω
+5 V
500 Ω
500 Ω
TB
T
TxD on/off RxD
PC = Master
Fig. 6.1 Bus connection via RS‐485
Up to 89 load cells can be connected via the RS‐485 interface to a common
bus line, the total length of which can be as much as 500 m. Bus cabling for
4­wire mode is shown in Fig. 6.1.
Remember that many PCs do not have an RS‐485 interface. In this case, you
need an interface converter, such as the HBM converter (see Section 6.2).
14
TB
TA
RB
RA
TA RB RA TB
T
R
TxD on/off RxD
FIT7A_1 = Slave 01
A03924_02_YI0_00 HBM: public
TA RB RA TB
...
R
Line termination
500 Ω
500 Ω
500 Ω
500 Ω
TA RB RA
T
R
TxD on/off RxD
FIT7A_89 = Slave 89
+5 V
+5 V
®
FIT 7A