Introduction: There are two power supplies available in the S7-1500 PLC, system power and load current. Today I mainly share with you how to choose the power supply in the Siemens S7-1500PLC, and which two power supplies are available. How to distinguish between system power and load current power, this article will give a detailed explanation!
System Power (PS)
System Power Provides Internal Requirements for Backplane Bus System voltage. This system voltage will power the module electronics and the LEDs. The system power supply can also supply power to the CPU or interface module when it is not connected to a 24 VDC load current supply.
Load Current Power (PM)
Load current power is not connected to the backplane bus to power the I/O loop of the stencil. In addition, the load current supply can be used to supply 24 VDC to the CPU and system power as needed. When the backplane bus is powered by the system power supply You can also choose to supply 24 VDC to the CPU.
In this case, you can configure up to 8 input/output modules for each CPU. Confirm that the power supply capacity is sufficient in STEP7 (TIA Portal), for example for CPs and CMs, additional power is required.
The three tables below give Possible configuration for powering the template.
1. Power the backplane bus only through the CPU
24 VDC is supplied to the CPU via the load current supply.Parameter assignment of the CPU: STEP 7 <General(General) Properties navigation Properties navigation In the area navigation, select Connect the power supply voltage L+ (Connection To supply voltage L+) option so that STEP 7 can correctly calculate the power balance.
2, powering the backplane bus only through system power
The system power supply located in slot 0 on the left side of the CPU supplies power to the CPU via the backplane bus. Parameter assignment of the CPU: in the "General" setting in STEP 7 (General) In the “Properties navigation” area navigation, select the “No connection to supply voltage L+” option to enable STEP 7 to properly balance the power supply. Calculation.
3. Powering the backplane bus through CPU and system power
Providing the allowed power supply voltage to the system power supply and providing 24 VDC to the CPU through the load current power supply Voltage. The parameter assignment of the CPU is the same as the first one. In the slot on the right side of the CPU, insert up to 2 system power supplies (power segments).