Siemens SIMATIC ET 200SP Function Manual

OPC UA communication
9.3 Using the S7-1500 as an OPC UA server
Communication
242 Function Manual, 11/2019, A5E03735815-AH
Subscription: Error in the sampling times
As of firmware V2.5 of the SIMATIC S7-1500 CPU, the OPC UA server can transmit the
status code "GoodOverload" when using subscriptions, if an overload of the CPU occurs
when sampling the items.
As of firmware V2.8 of the SIMATIC S7-1500 CPU, the OPC UA server can also enter this
event into the diagnostic buffer.
Requirement
In the OPC UA properties of the CPU, the option "Subscriptions: Sampling time errors"
(OPC UA > Server > Diagnostics) is selected.
Error-free subscription
In the case of an OPC UA subscription to various elements (such as tags), the OPC UA
server of the SIMATIC S7-1500 must check the elements for value changes at specified
intervals (sampling interval). This check, referred to as "sampling", requires some time,
which depends on the number and the data type of the items. After the sampling is
completed and a publishing request has been received, the server sends the elements to the
client.
Figure 9-51 Error-free subscription

Siemens SIMATIC ET 200SP Specifications

General

System Type	Distributed I/O System
Mounting	DIN Rail
Communication Protocol	PROFINET, PROFIBUS
IP Rating	IP20
Category	I/O Systems
Supply Voltage	24 V DC
Modularity	Yes
Hot Swapping	Yes
Storage Temperature	-40°C to +70°C
Digital Inputs	Yes
Digital Outputs	Yes
Analog Inputs	Yes
Analog Outputs	Yes
Communication Interface	PROFINET, PROFIBUS
Number of Modules	Up to 64
Relative Humidity	5 to 95% (non-condensing)
Operating Temperature	-25°C to +60°C