
5
SETTING OPERATION CONDITIONS
59
(b) MEMOBUS Frequency Reference Unit (o1
−
03, o1
−
04)
Enabled when bit 0 of register No. 0F is “1”. The frequency reference units, the frequen-
cy reference and output frequency monitors from master are indicated. The unit is 0.01
Hz when bit 0 of register No. 0 is “0”.
(c) MEMOBUS Slave Address (H5
−
01)
The slave address number is set. Set another slave address number connected on the same
transmission line.
21 22 23
9
10
25 27 26
33
18 19 20
1
2
3
4
5
6
7
8
13 14 15 16 17
11 35 36
42 43
41
40
37
ª
ª
E
E
OFF
485
422
SW1
SW2
1
2
Fig.
18
Arrangement of Control Circuit Terminals, SW1 and SW2
(3) Functions of SW1 and SW2
(a) SW1 (for terminating resistor)
Provide a terminating resistor to each receiver side when transmission is perfomed by
RS
−
422A (four
−
wire system) between one master and one slave. Provide a terminating
resistor in devices (both ends) connected to the communication cable when transmission
is performed by RS
−
485 (two
−
wire system) between one master and more than one slave.
The VS
−
616G5 is provided with a built
−
in terminating resistor. Switch the resistor ON/
OFF by SW1.
Table 27 Functions of SW1
Communication Cable
Connecting Method
SW1 Setting
Four
−
wire system (1 to 1)
Switch both 1 and 2 to the ON side (numbering side).
Two
−
wire system (1 to n)
Switch 1 to the OFF side and 2 to the ON side only for devices (both ends)
connected to the communication cable. For other devices, switch both 1 and
2 to the OFF side.
(b) SW2
Table 28 Functions of SW2
Transmission Method
SW2 Setting
RS
−
422A (four
−
wire system)
To 422 side
RS
−
485 (two
−
wire system)
To 485 side