Hitachi Vector Control with the SJ300 Inverter

(5-2) How many slaves can be connected?
There are two ways of connecting slave SJ300 to one master SJ300.
(5-2-1) Parallel connection
Maximum 10 slaves can be connected to a master based on RS422B EIAJ US. Actual capability is 32 units.
In this case, every slave follows the master with a minimum delay.
s RS422 standard
Load impedance of the driver R
L
> 100 Ω
Input impedance of the receiver R
in
> 4 k Ω
s Actual spec of SJ-FB
Load impedance of the driver R
L
> 100 Ω
Input impedance of the receiver R
in
= 12 k Ω
(5-2-2) Series connection
Any numbers of slaves can be connected to a master theoretically.
Delay in response will be bigger at far end.
In case of 32 slaves with SJ300;
RL = (12 k Ω / 32) // R
T
= 107 Ω > 100 Ω
∴ Capability is 32 units
Driver
(Master)
Receiver (Slave)
R
L
R
i2
R
i1
R
i32
1 2 32
Termination resistor R
T
(Internal)
Make it ON only at the furthest place.
150 Ω
Fig 13-1. Parallel connection of Master-Slave control
Driver
(Master)
Receiver (Slave)
R
L
1
Termination resistor R
T
(Internal)
Make it ON for every unit
2 n
Delay δ 1 Delay δ 2 Delay δ 3 Delay δ n
Total delay
= δ 1
Total delay
= δ 1+ δ 2
Total delay
= δ 1+ δ 2+ δ 3
Total delay
= Σδ n
Fig 13-2. Series connection of Master-Slave control