Danfoss FCM 300 Operating Instructions Manual page 9

FCM 300/FCD 300/VLT 2800 response time
The update time via the prodibus connection can be
divided in two parts: 1) The communication time, which
is the time it takes to transmit data from the master to
the slave (FCM 300/FCD 300/VLT 2800 with profibus),
and 2) the internal update time, which is the time it
takes to transmit data between the FCM 300/FCD
300/VLT 2800 control card and the profibus.
Data
Control word/Main reference (part of PPO)
Status word/Actual output frequency (part of PPO)
Parameter read (PCD 1-8)
Parameter write (PCD 1-2)
Parameter write (PCD 3-4)
Parameter write (PCD 5-8)
Parameter read (PCV)
Parameter write (PCV)
Acyclical data (single read, write)
System update time
The system update time is the time it takes to
update all the slaves in the network when using
8
FCM 300 / FCD 300 / VLT
®
2800 / DP V1 PROFIBUS
Communication time (t
com
transmission speed (baudrate) and the type of master
in use. The minimum obtainable communication
time with the FCM 300/FCD 300/VLT 2800 with
PROFIBUS is approx. 100 msec per slave, when
using DP communication with 4 bytes of data (PPO
type 3) at 3 Mbaud. More data or lower transmission
speed will increase the communication time.
The internal update time (t
of data in question as there are different channels for
the data transfer where time critical data e.g. control
word has highest priority. The internal update time for
the different types of data are stated below.
Update time, t
FCD 300/ VLT 2800
Max. 26 msec.
Max. 26 msec.
40 msec.
160 msec.
320 msec.
640 msec.
41 msec.
40 msec.
-
cyclical communication. The drawing below
shows the value which is obtainable in theory
at 2 input and 2 output bytes.
MG.90.A5.02 - VLT is a registered Danfoss trademark
) depends on the actual
) depends on the type
int
int
FCM 300
Max. 65 msec.
Max. 65 msec.
40 msec.
160 msec.
320 msec.
640 msec.
41 msec.
40 msec.
40 msec.