Modbus Timing; Interconnecting Analog Outputs - Siemens SINAMICS G120XA Operating Instructions Manual

Modbus timing

● p2024[0]: Maximum slave telegram processing time:
The time after which the slave must have sent a response to the master. 0 ms ... 10000 ms,
factory setting = 6000 ms.
● p2024[1]: Character delay time:
Character delay time: Maximum permissible time between the individual characters in the
Modbus frame. (Modbus standard processing time for 1.5 bytes).
● p2024 [2]: Inter-telegram delay:
maximum permissible time between Modbus telegrams. (Modbus standard processing time
for 3.5 bytes).
Values for p2024 [1] and p2024 [2]
Fieldbus monitoring time
Setting range: 0 ms ... 1999999 ms
The more slaves that are connected in the network, the longer the fieldbus monitoring time must
be.
If process data is not transferred within one cycle of the fieldbus monitoring time, then the
converter shuts down with fault F01910.
p2040 = 0 ⇒ bus monitoring deactivated.
Fieldbus error statistics
Displaying receive errors at the fieldbus interface

Interconnecting analog outputs

If you set communication via Modbus (p2030 = 2), then the analog outputs of the converter are
internally interconnected with the fieldbus analog outputs:
● p0771[0] = 791[0]
● p0771[1] = 791[1].
The values for p0791[0] and p0791[1] are written via registers 40523 and 40524.
Interconnections between parameter p0791 and other sources are rejected.
This means that the control outputs system-specific values via the analog outputs of the
converter.
However, if you still wish to display a converter-specific value, then you must adapt the
appropriate wiring.
Example
● AO 0 should display the value written via the control with register 40523. In this particular
case, no other settings are required in the converter.
● AO 1 should display the smoothed current actual value. To do this, you must set
p0771[1] = 27 (r0027 smoothed current actual value).
In this case, a write access via register 40524 to p0791[1] results in a fault message in the
control.
SINAMICS G120XA converter
Operating Instructions, 03/2019, FW V1.0, A5E44751205B AB
p2024[0 ... 2]
Table 6-8 Baud rates, transmission times, and delays (Page 154).
p2040 = 1000 ms
r2029
Advanced commissioning
6.2 Drive control
151