GE Industrial Solutions SG Series 750 T12 UL S2 Installation Guide - Manual (Page 40)

Modifications reserved Page 40/49
OPM_SGS_ISG_M75_M75_2US_V010.doc Installation Guide SG Series 750 UL S2 & SG Series 750 T12 UL S2
3.10.2 Parallel control bus connection
In cases of parallel operation, the communication between the units takes 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 links 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”.
All the parallel units are connected to the same control bus.
This connection allows:
•
The microprocessors 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 40 ft / 12 m.
Maximal overall length of bus connection, between the first and the last unit, should not be longer than
276 ft / 84 m.
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) and
JB (1/2/3/4/5) be connected or disconnected after the system has been powered On.
JA3
JA2
JB3
JB2
JB
JA1
JA
JP2
JB
JB1 JP1
JP1
IM 0048 JP2
JP4
JP3
JB2
JA2
JP3 JP4 JP4
JP1
JP2
JP1
JP4
IM 0048
JP3
JP3
JA1
JB1
JB
JP2
JA
UPS 3 UPS 2 UPS 1
JA1 + JB1
Next parallel
unit 4, 5, 6
JA3 + JB3 JA2 + JB2
SGS_750_RPA-IM0048_01US
JP1
JP4
JP2
JP2
JA
JP1
JP4
IM 0048
JP3
JP3
Fig. 3.10.2-1 RPA System - Control bus connection
The shield of the control bus cable, connected on JA and JB must be connected to ground with the
appropriate cable clamps fitted on the parallel bus socket.
It is important to place the units in sequence of their assigned number.
A unit number from 1 to 6 is defined by the setting of parameters and displayed on the panel (P1 to P6).
This number is also marked inside and outside the packaging.