User Manual

1.5.4 Using a RS-485 port
Ext. GND
Ext. 24V
11
12
13
14
GND
+
VS
D2
-
D2
+
7521/7521D
7522/7522D
7523/7523D
7522A/7522AD
7524/7524D
7527/7527D
Ext. GND
Ex
t.
24
V
7
8
9
1
0
GN
D
+
VS
D2
-
D2
+
7000
m
odu
l
e
Note:
• The RS-485 interface can directly drive 256 sets of 7000 modules without a
repeater
7521/2/2A/3/4/7 Series Hardware User’s Manual, Ver. 1.5 Sep/2002, 7Mh-001-15 -----35