Example Heat Dissipation Calculation - Allen-Bradley SLC 500 User Manual

Example Heat Dissipation
Calculation
Peripheral Device
Slot Number Catalog
Number
0 1747-L511
1 1746-BAS
2 1746-IA8
3 1746-OV8
Peripheral 1747-DTAM
Device
User Power to NA
Peripheral
(1) The user power on the 1746-P1 power supply for Chassis 2 is being used to power a peripheral (100 mA at 24V dc).
(2) This output card uses 5.5 Watts because only 10 points are on at any one time. Using the calculated watts formula - (number of p oints energized x watts per point) +
minimum watts = heat dissipation of module - the calculated watts for the 1746-OW16 module is 5.5W: (10 points x.33) + 5.17 = 5.5W.
Allen-Bradley PLCs
If your controller consisted of the following hardware components,
you would calculate heat dissipation as shown in the worksheet on
page G-8.
DTAM
Slot
The following table details the total watts dissipated by the modules
and peripheral devices in the above SLC 500 controller. The numbers
were taken from the tables on page G-3.
Chassis 1
Min. Watts Max. Watts
1.75 1.75
3.750 3.80
0.250 2.40
0.675 6.90
2.500 0 2.50
NA NA
Calculating Heat Dissipation for the SLC 500 Control System
Chassis 1
0 1 2 3
Slot Number Catalog
Number
4 1746-IA16
5 1746-IA16
6 1746-OW16
7 1746-OW16
NA NA
NA NA
Chassis 2
Slot
4 5 6 7
Chassis 2
Min. Watts Max. Watts
0.425 4.800
0.425 4.800
5.170
5.500
5.170 5.700
NA NA
(1)
NA
2.400
Publication 1747-UM011C-EN-P - December 2001
G-7
User Power to
Peripheral
(2)