Parallel Control Bus Connection - GE 8 Series Operating Manual

5.9.2 Parallel control bus connection

In cases of parallel operation, the communication between the units take place through the control bus
cables:
Each parallel unit is equipped with an additional board "P13 – RPA Board" where the connectors J52 (A)
and J62 (B) are located.
A short control cable provided with a ferrite ring core link the parallel board "P13 – RPA Board" with the
parallel bus socket on which must be connected the control bus cables JA and JB on PCB "P34- Bus
Interface (IM0048)".
All the parallel units are connected to the same control bus.
This connection allows:
•
The micro-processors of each unit to communicate with each other;
•
The oscillators of each unit to be locked together;
•
The regulation loops to compare the output current of each unit in order to equally share the load
current.
For increased reliability, this connection is made with redundant cables.
In this way, communication is maintained between units in case one of the control cables should fail or
be accidentally damaged or disconnected.
The standard length of the control bus cable between two parallel unit is 12 m / 40 ft.
Maximal overall length of bus connection, between the first and the last unit, should not be longer than
84 m / 276 ft.
Verify that control wiring is run in individual separate steel conduit.
NOTE !
Under no circumstance should the control bus cable connecting JA (1/2/3/4/5/6/7) and
JB (1/2/3/4/5/6/7) be connected or disconnected after the system has been powered On.
UPS 1
JP1
JP2
JP3
JP4
JB
JA
B
R
JB-1
P3
JA-1
The shield of the control bus cable, connected on JA and JB must be connected to ground with the
appropriate cable clamps fitted on parallel bus socket.
It is important to place the units in sequence of their assigned number.
A unit number from 1 to 8, is defined by the setting of parameters and displayed on the panel.
This number is also marked inside and outside the packaging.
Modifications reserved
OPM_SPE_XXX_10K_40K_8GB_V020.doc
P11
JB
A
P13
JB-2
JB-1
JA (1)
JB (1)
Fig. 5.9.2-1 RPA System - Control bus connection
UPS 2
P11
JA
B A
P13
R
JA-2
JA-1
P3
P2
JA (2)
JB (2)
UPS 3
P11
JB JA
B A
P13
R
JA-3
JB-3
JA-2
JB-2
P3
P2
Next parallel unit 4,5,6,7,8
Page 37/99
Operating Manual SitePro 10-15-20-30-40 kVA / S8
JA (3)
JB (3)