Siemens Simatic S7-400 - Manual (Page 541)

Interface Submodules
13-45
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
13.7.5 Conversion Time, Cycle Time, Settling Time, and Response
Time of the Analog Output Channels
Introduction
This section contains the definitions and relationships of times relevant to the
analog output modules.
Conversion Time
The conversion time of the analog output channels includes the transfer of the
digitized output values from the internal memory and the digital-analog conversion.
Settling Time
The settling time, that is, the time between the presence of the converted value and
reaching the specified value at the analog output, depends on the load. Here, a
distinction must be made between resistive, capacitive, and inductive load.
Response Time
The response time, that is, the time between the presence of the digital output
values in the internal memory and reaching the specified value at the analog
output, is, in the worst case, the sum of the cycle time and the settling time. The
worst case arises if the analog channel is converted shortly before transfer of a
new output value and converted back only after conversion of the other channels
(cycle time).
Figure 13-23 shows the response time of the analog output channels.
t
A
t
Z
t
E
t
1
t
2
t
A
= Response time
t
C
= Cycle time corresponds to n x conversion time (n = activated channels)
t
S
= Settling time
t
1
= New digitized output value available
t
2
= Output value received and converted
t
3
= Specified output value reached
t
3
Figure 13-23 Response Time of the Analog Output Channels