Connection of model
ALR121 with
external device
System configuration
External Device is Master
ALR121 is Master
1
: n
(n:up to 32 modules)
1
:
1
External
device
External
device
External
device
External
device
ALR121
ALR121
External
device
External
device
ALR121
ALR121
ALR121
ALR121
Figure 5.5.2-2 System Configuration When Connecting External Device with Model ALR121
l
Cables for Communication Modules
Yokogawa Electric Corporation provides RS-422/RS-485 cables shown in the following table.
If other type of cables is required, user needs to prepare separately.
Table 5.5.2-2 RS-422/RS-485 Communication Cables
Model
Cable Name
Remarks
AKB161
RS-422/RS-485 cable
Between ALR (M4 terminal) to external device (M3
terminal)
AKB162
RS-422/RS-485 cable
Between ALR (M4 terminal) to external device (M4
terminal)
n
FG Connection
Set up the RS-422/RS-485 shield as follows:
Ground the FG to the protective grounding system on the external device side.
The cable shield between ALR121 and the external device side must be connected to the FG
on the external device side. FG is not available on ALR121.
ALR121
The cable shield is connected to
the FG on the external device side.
External device
FG (Grounding Terminal)
Protective grounding system
SG
SG
FG
AKB161 or AKB162 cable
Figure 5.5.2-3 FG Connection
n
Connection with External Device
In the case that the external device is communication master, the four-wire type cable should
be used for connecting ALR121 and the external device. It has 1 to 1 and 1 to n connections.
<5.5 Connection of Communication Modules >
5-42
IM 32Q06C10-31E
4th Edition : Jan.30,2015-00
