Vecow UMBC-1100, Руководство пользователя

Страница: 37 / 79

30 ©Vecow UMBC-1100 User Manual GETTING TO KNOW YOUR UMBC-1100
2.3.3 SW1~SW5 : Pull-up and Pull-down Bias Resistors
When an RS-422 and RS-485 network is in an idle state, all nodes are in listen
(receive) mode. Under this condition there are no active drivers on the network,
all drivers are tristated. Without anything driving the network, the state of the LINE
is UNKNOWN. If the voltage level at the RECEIVER’s A and B inputs is less than
±200 mV the LOGIC level at the OUTPUT of the RECEIVERs will be the VALUE
of the last bit received. In order to maintain the proper idle voltage state, bias
RESISTORs must be applied to force the data LINEs to the idle condition.
4
1
1
5
6 10
11 15
1
10
19
11
12
24
1
A2 B2 A1 B1
A32 A31 B31 B32
A2 B2 A1 B1
A32 A31 B31 B32
143
288
222
79
220 77
146
1
143
288
222
79
220 77
146
1
143
288
222
79
220 77
146
143
288
222
79
220
77
146
1
2
1
4
1
4
1 4 1 4 1 4 1 4
8
7
1
2 8
7
1
2
8
7
1
2
8
7
1
2
8
7
1
2
8
7 1
2
8
7 1
2
8
7
1
2
7 1
7 1
7 1
7 1
7
1
7 1
7 1
12
11
1
2
10
1
10
1 10 1
10
1
10
1 10 1
10 1
10
1
10
1 2 3 4 5
22 25
U18
U14
U13 U10
U9 U5
U4 U1
R10
R9
R2
R1
L4
L3
L2 L1
U18 U14
U13
U10
U9
U5
U4 U1
R10
R9
R2
R1
L4 L3
L2 L1
R24
R12
R23 R11
R22
R10
R13
R1
L8 L5
L4 L1
30
20
B81
B82
A81 A82
B2 A2
A1 B1
SW1 SW2 SW3 SW4 SW5
RS232 RS422 RS485
JCOM1
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
JCOM2
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
JCOM3
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
JCOM4
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
JCOM5
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
8
7
6
5