Voltage Drop Considerations - Honeywell SEC-H-600 Installation Instructions Manual

Power Estimate Examples
Two example estimates are provided here, as follows:
• System 1, 8 door readers
• System 2, 10 door readers
SYSTEM 1, 8 DOOR READERS
This system requires 8 door readers and additional IO points requiring one SEC-H-RIO module. Two readers attach to the
Security Controller, the other 6 readers require 3 SEC-H-R2R modules (2 readers each). All readers draw 0.04A maximum, such
that power/battery calculations (Table 2) factor this in.
• Min. power supply (W) = 7.2W + (3 x 1.7W) + (1 x 6.0W) = 7.2W + 5.1W + 6.0W = 18.3W
• Min. backup battery (Ah) = 2.40Ah + (3 x 0.56Ah) + (1 x 2.0Ah) = 2.4Ah + 1.68Ah + 2.0Ah = 6.08Ah
In this case, a single 30W Enclosure Power Supply provides ample reserve, and the equipment could be housed in two
enclosures as follows:
• SEC-ENC-H-2 (large): SEC-H-600 controller, one SEC-H-RIO module, two SEC-H-R2R modules.
• SEC-ENC-H-3 (small): one SEC-H-R2R module.
The sealed lead acid Backup Battery in this case might be two 12V 7.0Ah types in parallel, providing 14.0Ah total. Between the
two Security Enclosures, module assemblies are wired together using 3-conductors for power/backup battery ("PS-", "PS+",
"BB").
SYSTEM 2, 10 DOOR READERS
The system requires 10 door readers and additional IO points requiring two SEC-H-RIO modules. Two readers attach to the
Security Controller, the other 8 readers require 4 SEC-H-R2R modules (2 readers each). Readers draw 0.13A maximum, such
that power/battery calculations (Table 2) factor this in.
• Total min. power supply (W) = 10.0W + (4 x 5.0W) + (2 x 6.0W) = 10.0W + 25.0W + 12.0W = 42.0W
• Min. backup battery (Ah) = 3.33Ah + (4 x 1.67Ah) + (2 x 2.0Ah) = 3.33Ah + 6.68Ah + 4.0Ah = 14.01Ah
Assuming that all equipment is located relatively nearby, it could be housed in two large enclosures, with each enclosure's 30W
power supply providing ample 15Vdc power to equipment inside, as follows:
• SEC-ENC-H-2 A (large): SEC-H-600 controller, one SEC-H-RIO module, two SEC-H-R2R modules (26W).
• SEC-ENC-H-2 B (large): One SEC-H-RIO, two SEC-H-R2R (16W).
Between Security Enclosures, module assemblies are wired together using 2-conductors for battery backup, that is "PS-" and
"BB". In this case, the sealed lead acid Backup Battery in this case might be two 12V 12.0Ah types in parallel, providing 24.0Ah
total.
NOTE: If the SEC-H-R2R and/or SEC-H-RIO expansion modules are mounted in remote locations from the Security Controller
and its backup batteries, or if a large system with multiple local power supplies, additional factors apply. See the next
sections "Voltage Drop Considerations" and "Maximum Output Load Considerations."

Voltage Drop Considerations

When using an Enclosure Power Supply and backup battery to power the Security Controller plus all expansion modules, and
some modules are not mounted in the same enclosure with the SEC-H-600, you must be aware of voltage drops in the
connecting "trunk power" cabling. Typically, this applies only if modules are located in different locations—that is, not in the same
enclosure or in adjacent enclosures.
NOTE: The 15Vdc power supply and the backup battery(ies) charged by the Security Controller must always be located in the
same Security Enclosure as the Security Controller.
Undersized selection of cabling can result in unacceptably high voltage drops, and expansion modules/attached readers may not
operate correctly—especially during emergency (battery backup) operation.
SEC-H-600 SECURITY CONTROLLER
7 95-7759—07