Operating Manual EMGZ470A/472A
15
8.4
Configuration
The configuration defines the amount of process data (byte and word) that is sent
during the cyclic communication from the control system to the measuring amplifier
and from the measuring amplifier to the control system. Normally a fixed value is set
with the programming tool of the control system.
To ensure maximum flexibility, several modules (telegram structure) can be chosen.
In a single measuring amplifier only one module can be set active at a time. The
terminology and structure of the modules base on the profiles described in the variable
speed drives section of the PROFIBUS user organization.
Module 1: Full control
3 bytes are transmitted from the control system to the measuring amplifier and vice
versa in each data cycle.
Byte 0
Byte 1
Byte 2
Request telegram
(Master
→
Slave)
Control byte
(STB)
Main reference value
Higher Byte
Main reference value
Lower Byte
Response telegram
(Slave
→
Master)
Status Byte
Status
Main feedback value
Higher Byte
Main feedback value
Lower Byte
Module 2: Feedback value with status
The control system sends periodically an empty telegram. The measuring amplifier
answers with the actual feedback value and with a status byte which indicates the
quality of the feedback value. This configuration can be used after offset and gain
adjustment has been completed. It can only be used if no process parameters of the
measuring amplifier are read or modified, or if the controller is not running the
evaluation the feedback value.
Byte 0
Byte 1
Byte 2
Request telegram
(Master
→
Slave)
empty
Response telegram
(Slave
→
Master)
Status Byte
Status
Main feedback value
Higher Byte
Main feedback value
Lower Byte
Module 2a: Feedback value with status
It’s identical with module 2 but the length of the response telegram is 4 Byte. The higher
status byte is not used and therefore contains all 0.
Byte 0
Byte 1
Byte 2
Byte 3
Request telegram
(Master
→
Slave)
empty
Response telegram
(Slave
→
Master)
00000000
Higher Byte
Status Byte
Lower Byte
Main
feedback
value
Higher Byte
Main
feedback
value
Lower Byte
