Connect Tech DFlex-4/104 - Manual (Page 81)

Chapter 4: Appendix H - 20mA Current Loop 4-31
DFlex-4/104 User's Manual, ver. 0.04
Current Loop Cable Wiring
You can wire DFlex-4/104 adapters with the 20mA Current Loop
option in various ways to communicate with 20mA Current Loop
peripherals. This section will descibe a few examples of current
loop cabling schemes.
Figure 21 describes a 4 wire cabling scheme between a port on
the DFlex-4/104 adapter to another port on the DFlex-4/104
adapter.
Figure 21: Current Loop wiring diagram (4 wire)
1
8
2
7
RxD +
TxD +
RxD -
TxD -
4
7
9
8
20mA
20mA
TxD +
RxD -
RxD +
TxD -
3
2
6
1
XMTR
HCPL 4100
RCVR
HCPL 4200
TxD Source
TxD Return
RxD Source
RxD Return
Optically isolated station
(Passive transmitters/receivers)
Non-isolated station
(Active transmitters/receivers)
Port 1
DB-9 male
Port 2
DB-9 male
I
SRC
XMTR
HCPL 4100
RCVR
HCPL 4200
I
SRC
Note:
The example above illustrates a 20mA current loop cable wiring
configuration between one port of an DFlex-4/104 adapter and
another port of an DFlex-4/104 adapter. This example shows
wiring for both active and passive modes