The CPU 315-2 PN/DP is a CPU with medium-sized program memory. It is used in plants containing distributed automation structures in addition to a centralized I/O. It can be implemented as a PROFINET IO controller and as a standard PROFIBUS DP master in the SIMATIC S7-300. The 315-2 PN/DP CPU can also be used as distributed intelligence (PROFIBUS DP slave or PROFINET I-Device).
The CPU 315-2 PN/DP is an ideal platform for simple software-implemented technological tasks, e.g.:
Motion control with Easy Motion Control.
Implementation of control engineering tasks using STEP 7 blocks or runtime software Standard PID Control/Modular PID Control.
An extended process diagnosis is possible by using SIMATIC S7-PDIAG.
The integrated communication options of the CPU enable networked automation solutions to be implemented without additional components.
The CPU 315-2 PN/DP is equipped with the following:
Microprocessor; the processor can handle execution times of approx. 50 ns per binary instruction and 450 ns per floating-point instruction.
384 KB main memory (corresponds to approx. 128 K instructions); the extensive work memory for for program components relevant to execution offers sufficient space for user programs. SIMATIC Micro Memory Cards (8 MB max.) as load memory for the program also allow the project to be stored in the CPU (complete with symbols and comments) and can be used for data archiving and recipe management.
Combined MPI/DP interface; the first integrated MPI/DP interface can establish up to 16 connections simultaneously to the S7-300/400 or connections to PGs, PCs and OPs. One of the connections is permanently reserved for programming devices and one for OPs. The MPI supports simple networking of up to 32 CPUs over “Global data communication”. This interface can be reconfigured from MPI interface to DP interface. PROFIBUS DP interface: The DP interface can be used as a DP master or as a DP slave. PROFIBUS DP slaves can be operated isochronously on this interface. The PROFIBUS DP V1 standard is fully supported. This increases the scope of DP V1 standard slaves in terms of diagnostics and parameterization capability.
Ethernet interface; the second integral interface of the CPU 315-2 PN/DP is a PROFINET interface with a 2-port switch, based on Ethernet TCP/IP. It supports the following protocols:
S7 communication for data communication between SIMATIC controllers;
PG/OP communication for programming, startup and diagnostics through STEP 7;
PG/OP communication for interfacing to HMI and SCADA;
Open TCP/IP, UDP and ISO-on-TCP (RFC1006) communication over PROFINET;
SIMATIC NET OPC-Server for communication with other controllers and I/O devices with own CPU
Password protection; a password concept protects the user program from unauthorized access.
Block encryption; the functions (FCs) and function blocks (FBs) can be stored in the CPU in encrypted form by means of S7-Block Privacy to protect the know-how of the application.
Diagnostics buffer; the last 500 error and interrupt events are stored in a buffer for diagnostic purposes.
Maintenance-free data backup; the CPU automatically saves all data (up to 128 KB) in case of a power failure so that the data are available again unchanged when the power returns.
The S7 configuration as well as the properties and response of the CPUs can be parameterized using STEP 7:
General; definition of the name, system ID and location ID.
Startup; definition of the startup characteristics of the CPU and the monitoring time
Synchronous cycle interrupts; setting of DP master system, process image partition number, and delay time
Cycle/clock memory; specification of the maximum cycle time and load. Setting of the clock memory address. Enabling prioritized HMI communication
Retentivity; setting retentive areas
Clock interrupts; setting the start date, start time and periodicity
Watchdog interrupts; setting of periodicity
System diagnostics; determining handling and scope of the diagnostic alarms
Clock; setting the type of synchronization in the AS or on the MPI
Protection level; specifying the access rights to program and data
Communication; reservation of connection resources
Web; settings for the Web server of the CPU
MPI/PROFIBUS DP interface; setting the interface type. Determining node addresses. Parameterizing the operating mode and configuring the transfer areas in the case of PROFIBUS DP. Parameterizing the time synchronization
PROFINET interface; setting of addresses. Parameterizing the PROFINET properties, the I-Device functionality, the type of synchronization on PROFINET, the time synchronization using NTP procedure, the media redundancy, and the KeepAlive function. Parameterizing port 1 and port 2
Display and information functions
Status and error indications; LEDs indicate hardware, programming, time, I/O and bus errors, and operating statuses such as RUN, STOP and start-up.
Test functions; the PG is used to indicate signal states during program execution, to modify process variables independently of the user program and to output the contents of stack memories.
Information functions; the PG can be used to obtain information about the memory capacity and operating mode of the CPU, the current loading of the work and load memory, current cycle times and diagnostics buffer content in plain text.
Integrated communication functions
Global data communication
S7 basic communication
Data record routing
PROFIBUS DP master/slave
Open communication over TCP/IP, ISO-on-TCP and UDP
PROFINET IO controller
The CPU provides many extensive system functions for diagnostics, parameterization, synchronization, alerting, time measurement, etc.