Honeywell CIPer 50 Installation & Commissioning Instructions page 71

NOTE
• Use a noise-free earth ground inside the cabinet.
• If a field device that prohibits earth grounding is connected to the system ground, an
isolation monitoring device must be used instead of earth grounding.
Connect earth ground to the respective terminal of the CPU, see Figure 60
L
LINE
N
L
LINE
N
Figure 59: Connecting and earthing multiple CPUs (RECOMMENDED USE OF SEPARATE
Example 2:
When connecting multiple CPUs to a single transformer, it is imperative that the polarity of the power supply
terminals of the CPUs and the polarity of the transformer always correspond (namely: 24V-0 of the
transformer must always be connected to 24V-0 of the CPU, and 24V~ of the transformer must always be
connected with 24V~ of the CPU).
Depending upon the individual CPU, the numbering of the corresponding two terminals may possibly deviate
from the norm (which is usually "terminal 1 = 24V-0" and "terminal 2 = 24V~"). In the following example, CPU 3
has a deviating numbering and must be connected accordingly.
NOTE
• When using a single transformer for several CPUs, each CPU ground must be wired
separately to the star-point.
• If the field device transformer is physically far away from the CPUs, earth grounding must
still be performed for the controller.
• Use one star-point to split power for multiple CPUs and field devices.
CIPer MODEL 50 CONTROLLER – INSTALLATION AND COMMISSIONING INSTRUCTIONS
TM
CPU 1
24V~0 24V~
RS485-2 + RS485-2 -
1 2 29 30
24 V~
24 V~0
NOISE-FREE EARTH GROUND
(ONLY ONE PER SYSTEM)
CPU 2
24V~0 24V~
RS485-2 + RS485-2 -
1 2 29 30
24 V~
24 V~0
NOISE-FREE EARTH GROUND
(ONLY ONE PER SYSTEM)
I/O MODULE
COM COM
24V~ 24V~0
A B
71 72 73 74
RECOMMENDED
TRANSFORMERS)
71
I/O MODULE
COM COM
24V~ 24V~0
A B
71 72 73 74
24 V~
Y
GND
31-00233-02