Siemens Simatic S7 Series User Manual

49
Analog Input Example Analog inputs can be used for a variety of purposes. In the
following example, a scale is connected to a load cell. A load
cell is a device that generates an electrical output proportional
to the force applied.
Scale
0 to 10 VDC Analog Signal to PLC
Desired Weight = 25 LBS = 5 VDC
Inspection
Station
Finished
Goods
Inventory
Package Route
Controled by PLC
The load cell in this example converts a value of weight from 0
to 50 pounds into a 0 - 10 VDC analog value. The 0 - 10 VDC load
cell signal is connected to an S7-200 PLC’s analog input.
The analog value applied to the PLC can be used in various
ways. For instance, the actual weight can be compared to a
desired weight for a package. Then, as the package is moved
on a conveyor, the S7-200 PLC can control a gate to direct
packages of varying weight.
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Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.