User guide
Watlow EZ-ZONE
®
 RMH Module  • 34 •  Chapter 2 Install and Wire 
Connecting and Wiring the Modules
RMH Module Connections
The RMH module can be installed as a stand-alone 
limit controller or can be interconnected on the DIN 
rail as shown below with other RM family modules. 
When modules are connected together as shown, 
power and communications are shared between mod-
ules over the modular backplane interconnection. 
Therefore, bringing the necessary power and commu-
nications wiring to any one connector in slot C is suf-
ficient. The modular backplane interconnect comes 
standard with every module ordered and is generic 
in nature, meaning any RM modules shown below on 
RM Controller
 Module
RM High Density
 Module
RM Access
  Module
RMCxxxxxxxxxAxx
RMHx-xxxx-xAxx RMAx-xxxx-xxx
Slot C
Slot C
Slot C
_
_
_
_
_
_
_
_
Slot A
Slot A
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
Slot D
_
_
_
_
_
_
_
_
Slot D
_
_
_
_
_
_
_
_
Slot D
Slot A
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
_
Slot E
CE
CD
CF
99
98
RUI
EZKB-_ A _ _- _ _ _ _
RM Controller
  Module
RM Expansion
  Module
RMCxxxxxxxxxAxx
_
_
_
_
_
_
_
_
Slot A
_
_
_
_
_
_
_
_
Slot D
_
_
_
_
_
_
_
_
Slot E
_
_
_
_
_
_
_
_
Slot B 
RMEx-xxxx-xxxx
Slot C
_
_
_
_
_
_
_
_
Slot A
_
_
_
_
_
_
_
_
Slot D
_
_
_
_
_
_
_
_
Slot E
_
_
_
_
_
_
_
_
Slot B 
Split Rail Configuration
Standard Bus 
 Address 4
Standard Bus 
 Address 5
Standard Bus 
 Address 1
Standard Bus 
 Address 2
Standard Bus 
 Address 3
Standard Bus
Inter-module
  Bus
CY
CX
CZ
CE
CD
CF
99
98
Slot B 
_
_
_
_
_
_
_
_
Slot B 
_
_
_
_
_
_
_
_
Slot E
_
_
_
_
_
_
_
_
Slot E
_
_
_
_
_
_
_
_
Slot B 
_
_
_
_
_
_
_
_
CY
CX
CZ
CE
CD
CF
99
98
CY
CX
CZ
CE
CD
CF
99
98
CY
CX
CZ
CE
CD
CF
99
98
CY
CX
CZ
CE
CD
CF
99
98
Slot C
Power Supply
Low Voltage
  Class 2
Standard Bus
Modular backplane interconnect
the DIN rail can use it.
Notice in the split rail system diagram that a 
single power supply is being used across both DIN 
rails. One notable consideration when designing the 
hardware layout would be the available power sup-
plied and the loading affect of all of the modules 
used. Watlow provides three options for power sup-
plies listed below:
1. 90-264 Vac to 24Vdc @ 31 watts (Part #: 0847-
0299-0000)
2. 90-264 Vac to 24Vdc @ 60 watts (Part #: 0847-
0300-0000)
3. 90-264 Vac to 24Vdc @ 91 watts (Part #: 0847-
0301-0000)
With regards to the modular loading affect, maxi-
mum power for each RM module is listed below:
1. RMCxxxxxxxxxxxx @ 7 watts / 14VA 
2. RMEx-xxxx-xxxx @ 7 watts / 14VA 
3. RMAx-xxxx-xxxx @ 4 watts / 9VA
4. RMLx-xxxx-xxxx @ 7 watts / 14VA 
5. RMHx-xxxx-xxxx @ 7 watts / 14VA 
6. RMSx-xxxx-xxxx @ 7 watts / 14VA 
So, in the split rail system diagram, the maximum 
current draw on the supply would be 38 Watts.
  - 2 RMC modules consumes 14W
  - 1 RMH module consumes 7W
  - 1 RME modules consumes 7W
  - 1 RMA module consumes 4W
  - 1 Remote User Interface consumes 6W
With this power requirement (38 watts) the second or 
third power supply could be used.
Another hardware configuration scenario that could 
present itself (graphic not shown) would be a con-
figuration that requires more than one supply. Lets 
make some assumptions pertaining to the split rail 
system diagram shown below. The power supply 
used is the 91W supply. The top DIN rail now has 
the following modules:
  - 2 RMC modules consumes 14W
  - 1 RMA consumes 4W
  - 11 RME modules consumes 77W
  - 2 RMH modules consumes 14W
As can now be seen, the total power requirement 
exceeds 91W. In this case, another power supply 
would be required. To incorporate another supply in 
this system simply disconnect pins 99 and 98 on the 
remote DIN rail and connect another appropriately 
sized power supply for the remote modules to those 
same pins.
When using a split rail configuration ensure that 
the interconnections for the Inter-module Bus and 
Standard Bus do not exceed 200 feet. Standard Bus 
and the Inter-module Buses are different protocols 
and both are required for split rail configurations. 
Without having both connected communications be-
tween modules would not be possible.
Note:
Unit is not provided with a disconnect, use of an 
external disconnect is required. It should be located 
in close proximity to the unit and be labeled as the 
disconnect for the unit.










