Johnson JR8 Serie Guide D'utilisation page 118

CAUTION
If the total distance is less than or equal to 200m and the total number of IDUs is less than or equal to 10 sets, the
valve is powered and controlled by the master ODU.
If the total distance is longer than 200m or the total number of IDUs is more than 10 sets, a repeater is required to
increase the bus voltage.
The load capacity of the repeater is the same as that of the ODU, and it can load a bus length of 200m or 10 IDUs.
A maximum of two repeaters can be installed in the same refrigerant system.
The number of IDUs requiring power supply in the same refrigerant system is less than or equal to 30 sets.
Keep the power on/off for both the repeater and the ODUs, or the repeater use an uninterruptible power supply.
For repeater installation, please refer to the repeater installation manual. Do not reversely connect the upstream and
downstream IDU ports of the repeater; otherwise, it will cause a communication failure.
If the separate power supply function needs to be enabled in the system, need to be enabled on the master ODU. For
details, refer to section 7.5.
39
V.1