Honeywell Analog Input Remote Terminal Panel (RTP) Note 6 (NOT FOR SIL2 SYSTEMS) 900RTA-L001
*Limit 10, 4 channel Analog Output modules per I/O rack.
*Limit 4 PFQ modules per I/O rack.
Total mA @ 5V =
Total mA @ 24V=
Complete columns A, D and E above.
1. Is column D total mA @ 5V less than 2000mA? Yes/No
2. Is column E total mA @ 24V less than 900mA? Yes/No
3. If the answers to 1 and 2 are YES, go to 4. If the answer to 1 or 2 is NO, use power supply 900P01-0001.
4. Multiple column D total by 5.1
5. Multiple column E total by 24.5
6. Sum results of 4 and 5. ( )
7. Divide results of 6 by 1000 ( )
8. Is the result of 7 less than 28? Yes/No
If the answer to 8 is Yes, use power supply 900P02-0001
If the answer to 8 is No, use power supply 900P01-0001
DC Power Supply
The P24 DC power supply is for use with +24V input power applications. The wattage rating is the same as
the P01, 60W.
Rack Orientation and Mounting
Racks must be mounted as indicated in illustrations throughout this manual, so as to provide for vertical
airflow through the racks. That is, racks must never be mounted vertically, and must never be mounted
with the backplane horizontal (for example, flat on a horizontal panel or tabletop). Environmental
specifications apply only to the normal mounting configuration.
Rack dimensions, including overall dimensions and patterns for drilling holes for mounting, are given in
Figure 24 and Figure 25. Vertical spacing of racks, which is required for rack ventilation and for routing
wires, is shown in Figure 26.
Figure 24 – Rack Dimensions
Remote Termination Panels
If your controller will be mounted in a separate panel with intermediate terminations between field wiring
and controller wiring, consider using RTPs to replace the intermediate terminations. Pre-wired cable
assemblies for the RTPs eliminate the need for separate wiring terminations between the controller and the
intermediate terminal boards. For details see page 217.
Environment
The HC900 Controller must be mounted in suitable equipment enclosures. That is, all components such as
the Controller rack, I/O Racks, and the 900CS Control Station manufactured by Honeywell must be
mounted in approved furniture designed for industrial applications.
Consideration should be given to the installation so that the potential for the build-up of static electricity is
minimized or eliminated.
See Environmental Conditions and Approvals on page 210.

Heat Rise De-rating
The HC900 is rated to operate at 60o C. However, for maximum reliability, the following guidelines should
be observed for applications above 52o C.
1. Locate lower-power modules (Analog Input, Contact Input, etc) beside the Controller/Scanner Module,
and keep higher-power modules (AC Output, AC Input, etc) away from it. For power consumption of
each module, see Table 4.
2. For 240 Vac applications and temperatures above 56o C, or 264Vac, 52o C, de-rate the number of ON
inputs per AC input module. (See AC Input de-rating data, see Figure 27.)
3. Limit the number of Analog Output modules to a maximum of 10 per rack. (see Figure 28)
Table 4 – Power Applied, by Module Type
Module HC900 Hardware
Power (Watts)
Field Power
(Watts)
Total Power
(Watts)
Controller C30 and C30S 6.0 0.0 6.0
Controller C50 and C50S 6.0 0.0 6.0
Controller C70 and C70S 7.1 0.0 7.1
Controller C75 and C75S 7.8 0.0 7.8
Redundancy switch module (RSM) 0.1 0.0 0.1
Power Status Module (PSM) 0.1 0.0 0.1
Scanner 1 Port (S50/S50S) 3.9 0.0 3.9
Scanner 2 Port (S75/S75S) 5.0 0.0 5.0
Analog Input (Universal) 0.8 0.0 0.8
Analog Input (High level) 1.6 0.0 1.6
Analog Output (4 points) 5.1 0.0 5.1
Analog Output (8 pts. internal 24V) 9.4 0.0 9.4
Analog Output (8 pts. external 24V) 1.1 8.3 9.4
Analog Output (16 pts. internal 24V) 18.3 0.0 18.3
Analog Output (16 pts. external 24V) 1.7 16.6 18.3
Contact Input 1.6 0.0 1.6
Relay Output 3.0 0.0 3.0
16 pt DC In (@ 24V) 0.7 2.6 3.3
16 pt DC In (@ 32V) 0.7 5.1 5.7
32 pt DC In (@ 24V) 1.1 3.1 4.2
32 pt DC In (@ 32V) 1.1 5.1 6.2
16 pt DC Out 1.7 1.2 2.9
32 pt DC Out 1.2 1.8 3.0
AC In (@120V) 0.7 1.9 2.6
AC In (@240V) 0.7 7.7 8.3
AC/DC In 0.7 7.7 8.3
AC Out 1.1 12.0 13.1
PFQ 6.7 0.1 6.8
Cable/Wiring Distance Planning
For all installations observe the following guidelines.
Maximum length of RS-232 cabling (Controller to PC) is 50 feet (15.2 meters).
Maximum length of RS-485 cabling is 2000 feet (609.6 meters).
For Ethernet connections, cable length must be less than 100m. For greater than 100m a switch is
required. The use of Ethernet cables in excess of 100 meters and/or devices other than recommended
Switches will cause transmission delays on the I/O link which could have adverse affects on Controller
performance.
You can also use fiber optic cable for connections between the controller and a remote rack. Please refer
to HC900 specification document (51-52-03-31) for more details.
With redundant CPUs, when using 2 or more I/O racks an Ethernet switch is required between each CPU
and the I/O racks. Use Honeywell-approved switches only. (see page 215)
Maximum of 2 switches between each CPU’s I/O port and all I/O racks.
Cable lengths specified in this manual are absolute. When planning for routing of cables and wires, be
certain to include vertical and horizontal routing within cabinets, raceways, and conduits.
It is advantageous to minimize length of I/O wiring. However, it is also a good idea to locate racks (and
wiring) away from adverse environmental conditions such as sources of RFI, EMI, and away from areas
with high levels of moisture, dust, and corrosive materials.