Rlmax = .085(rmin) – Fire-Lite M302(A) Two-Wire Conventional Detector Monitor Modules User Manual
Page 3

Figure 5.
RISER POWER SUPPLY AND WIRE RESISTANCE CALCULATIONS
The power source must be capable of supplying a minimum amount of current to a riser circuit of monitor modules. It is accept-
able in some jurisdictions to supply the minimum current required to allow a percentage of monitor modules to be in the alarm
state while the remaining monitor modules are in the standby state. The formulas below are provided for calculating the maxi-
mum current required from a power supply (Imax) to support a riser circuit of monitor modules with a percentage of monitor
modules in the alarm state.
Imax = Vmax/Rmin
Rmin = 2060/( 2.68 * Na) + (N )
Where:
(Na)
is the number of monitor modules required to be supported in the alarm state; and
(N)
is the total number of monitor modules on a given riser circuit.
Example:
Na = 5, N = 15
Rmin = 72.5 = 2060/( 2.68 * 5) + (15 )
The constants were derived by reducing equations that utilize the internal resistances of the module under worst case conditions.
Designing a system where it is permitted to support a percentage of modules in the alarm state allows a longer wire run for the
riser circuit. The following formula is provided for calculating the maximum resistance (Rlmax) of the wire run for the riser circuit.
Rlmax = .085(Rmin)
The constant was derived by reducing equations that were written from a low battery supply voltage of 20.4 VDC and the min-
imum supply voltage of 18.8 VDC required for proper operation of the module.
The following table is provided for calculating the maximum cable length allowed for a given riser circuit if Belden cable is used.
Resistance of a pair of conductors in 1000 feet of Belden cable:
Belden 9571 (18 AWG solid copper, twisted pair)
12.6
Ω
Belden 9574 (18 AWG solid copper, twisted-shielded pair)
12.4
Ω
Belden 9572 (16 AWG solid copper, twisted pair)
8.2
Ω
Belden 9575 (16 AWG solid copper, twisted-shielded pair)
8.2
Ω
Belden 9580 (14 AWG solid copper, twisted pair)
5.0
Ω
Belden 9581 (14 AWG solid copper, twisted-shielded pair)
5.0
Ω
Belden 9582 (12 AWG solid copper, twisted pair)
3.2
Ω
Belden 9583 (12 AWG solid copper, twisted-shielded pair)
4.0
Ω
C300 SERIES CONTROL MODULE SWITCHING POWER SUPPLY
F400-09-00
3
I56-631-06
1 (-)
2 (+)
MODULE
(+)
(-)
CONTROL
9
8
7
6
5
3
4
J1 & J2
FORM C RELAY OPERATION
WHEN BOTH TABS
J1 & J2 ARE BROKEN
RELAY CONTACT RATINGS:
RESISTIVE:
INDUCTIVE:
PILOT DUTY:
2 A @ 30 VDC
1 A @ 30 VDC (.6 PF)
.6 A @ 30 VDC (.35 PF)
.3 A @ 110 VDC (.35 PF)
.3 A @ 120 VAC (.35 PF)
FROM PANEL OR
(+)
(-)
SEE REQUIREMENTS ON PAGE 4.
POWER SUPPLY, LISTED FOR FIRE
PROTECTION WITH BATTERY BACKUP
(+)
(-)
(MONITOR LOSS OF PRIMARY POWER)
CONTACTS SHOWN IN STANDBY.
CONTACTS MAY HAVE SHIFTED TO THE
ACTIVATED STATE DURING SHIPPING.
CONTROL MODULE MUST BE MADE TO
COMMUNICATE WITH THE PANEL PRIOR
TO CONNECTING CIRCUITS CONTROLLED
BY THE MODULE.
TO NEXT
(+)
(-)
DEVICE
CONNECT MODULES TO LISTED COMPATIBLE
ADDRESSABLE FIRE-LITE CONTROL
PANELS ONLY.
32 VDC MAX.
SEE FIRE-LITE PRODUCT MANUAL
FOR WIRE SPECIFICATIONS
(+)
(-)
PREVIOUS DEVICE
SWITCHED RISER
CIRCUIT FOR
INTERFACE MODULES
C300 CONTROL MODULE
IS NOT REQUIRED IF
SWITCHABLE POWER
IS AVAILABLE.
COMMUNICATION LINE
C304(A)
A2396-631
NORMALLY OPEN
NORMALLY CLOSED
RELAY COMMON
(SHIELD)
(SHIELD)