STATUS SCIENTIFIC CONTROLS MCU3 - Calculation Examples

STATUS SCIENTIFIC CONTROLS
MCU System Installation and Hardware Configuration Manual
TD06/001
Issue:
6
Change Note:
1696
Page 1-12
1.6.1 Calculation Examples
Three examples follow demonstrating how the backup time may be calculated.
Example 1 (Typical Configuration)
A 4 channel system comprising of 3 toxic channels and 1 flammable channel. All system relays
are configured as normally energised. No analogue outputs are being provided by the system.
Module and Detector Heads
Qty
Current
Controller & Display
1
x
36
=
36
mA
Input Module & Toxic Head
3
x
8
=
24
mA
Input Module & Oxygen Head
0
x
17
=
0
mA
Input Module & Flammable Head
1
x
41
=
41
mA
Common Relays (Energised)
4
x
17
=
68
mA
Input Module Relays (Energised)
12
x
17
=
204
mA
Input Module Analogue Output
0
x
4
=
0
mA
Total Current Required under normal conditions =
373
mA
Batteries are 1.2Ahr, therefore backup time is 1200/373 = 3.2 Hrs = 3 Hours 12 mins
Example 2 (Worst Case)
An eight channel system comprising of 8 flammable channels. All system relays are configured as
normally energised. All analogue outputs are providing signals to external equipment.
Module and Detector Heads
Qty
Current
Controller & Display
1
x
36
=
36
mA
Input Module & Toxic Head
0
x
0
=
0
mA
Input Module & Oxygen Head
0
x
0
=
0
mA
Input Module & Flammable
8
x
41
=
328
mA
Common Relays (Energised)
4
x
17
=
68
mA
Input Module Relays (Energised)
24
x
17
=
408
mA
Input Module Analogue Output
4
x
4
=
16
mA
Total Current Required under normal conditions =
856
mA
Batteries are 1.2Ahr, therefore backup time is 1200/856 = 1.4 Hrs = 1 Hour 24 mins