294 Rockwell Automation Publication 1766-UM001O-EN-P - September 2021
Appendix H System Loading and Heat Dissipation
Validating the System
The example systems shown in Table 47 and Table 48 are verified to be
acceptable configurations. The systems are valid because:
• Calculated Current Values < Maximum Allowable Current Values
• Calculated System Loading < Maximum Allowable System Loading
System Loading Worksheet Table 49, Table 50, and Table 51 are provided for system loading validation. See
System Loading Example Calculations
on page 293.
1762-OB32T 175 0
1762-OF4 40 165
1762-OV32T 175 0
1762-OW8 2 80 90 160 180
1762-OW16
140
(2)
180
(2)
1762-OX6I 110 110
1762-IQ8OW6 110 80
Total Modules (7 maximum): 4 Subtotal: 260 180
(1) See your expansion I/O Installation Instructions for Current Requirements not listed in this table.
(2) Only applicable for Series B and Series C I/O modules.
Table 46 - Calculating the Current for Expansion I/O (Continued)
Catalog Number
(1)
n A B n x A n x B
Number of Modules
Device Current Requirements (max) Calculated Current
at 5V DC (mA) at 24V DC (mA) at 5V DC (mA) at 24V DC (mA)
Table 47 - Validating Systems using 1766-L32AWA, or 1766-L32BXB
Maximum Allowable Values Calculated Values
Current: Current (Subtotal from Table 46 on page 293.):
1225 mA @ 5V DC 1155 mA @ 24V DC 0 mA + 260 mA = 260 mA @ 5V DC 0 mA + 180 mA = 180 mA @ 24V DC
System Loading: System Loading:
33.845 W
= (260 mA x 5V) + (180 mA x 24V)
= (1,300 mW) + (4,320 mW)
= 5,620 mW
= 5.62 W
Table 48 - Validating Systems using 1766-L32BWA
Maximum Allowable Values Calculated Values
Current for Devices Connected to the +24V DC Sensor
Supply:
Sum of all sensor currents
250 mA @ 24V DC 140 mA @ 24V DC (example sensor value)
Current for MicroLogix Accessories and Expansion I/O: Current Values (Subtotal from Table 46 on page 293
):
1225 mA @ 5V DC 1155 mA @ 24V DC 0 mA + 260 mA = 260 mA @ 5V DC 0 mA + 180 mA = 180 mA @ 24V DC
System Loading: System Loading:
39.845 W
= (140 mA x 24V) + (260 mA x 5V) + (180 mA x 24V)
= (3,360 mW) + (1,300 mW) + (4,320 mW)
= 8,980 mW
= 8.98 W