Mitsubishi Electric MELSERVO-J4 MR-J4 TM Instruction Manual page 317

11. OPTIONS AND PERIPHERAL EQUIPMENT
(b) When connecting two brake units to a servo amplifier
POINT
To use brake units with a parallel connection, use two sets of FR-BU2 brake
unit. Combination with other brake unit results in alarm occurrence or
malfunction.
Always connect the terminals for master/slave (MSG to MSG, SD to SD)
between the two brake units.
Do not connect the servo amplifier and brake units as below. Connect the
cables with a terminal block to distribute as indicated in this section.
Servo amplifier
P+
N-
Connecting two cables to
P+ and N- terminals
Brake unit
P/+
N/-
Brake unit
P/+
N/-
11 - 24
Servo amplifier
Brake unit
P+ P/+
N- N/-
Brake unit
P/+
N/-
Passing wiring