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FC 300 Profibus
PCV Parameter Access
Parameter access via the PCV channel is performed by the PROFIBUS DP V0 cyclical data exchange, where
the PCV channel is part of the PPOs described in the chapter How to Control the FC 300.
PCV
PCA
IND
Byte
1
2
3
4
no.
Type
1:
Type
2:
Type
5:
PCV:
Parameter Characteristics Value
PCD:
Process Data
PCA:
Parameter Characteristics (Bytes 1, 2)
IND:
Sub index (Byte 3. Byte 4 is not used)
PVA:
Parameter value (Bytes 5 to 8)
CTW:
Control word
STW:
Status word
MRV:
Main reference value
MAV:
Main actual value (Actual output frequency)
Using the PCV channel it is possible to read and write parameter values, as well as readout of a number of
describing attributes of each parameter.
PCA Handling
The PCA part of PPO types 1, 2 and 5 can handle several tasks. The master can control and supervise
parameters and request a response from the slave, whereas the slave can respond to a request from
the master.
Requests and responses is a handshake procedure and cannot be batched, meaning that if the master sends
out a read/write request, it has to wait for the response, before it sends a new request. The request or
response data value will be limited to maximum 4 bytes, which implies that text strings are not transferable.
For further information, please see the Application Examples chapter.
PCA - Parameter Characteristics
15
14
13
RC
RC: Request/response characteristics (Range 0..15)
SMP: Spontaneous Messag (Not supported)
PNU : Parameter no. (Range 1..1999)
How to Access FC 300 Parameters
1
2
PVA
CTW
MRV
STW
MAV
5
6
7
8
9
10
11
12
12
11
10
9
SMP
MG.33.C2.02 - VLT is a registered Danfoss trademark
PCD
3
4
5
6
PCD
PCD
PCD
PCD
13
14
15
16
17
18
19
20
8
7
6
5
PNU
7
8
9
10
PCD
PCD
PCD
PCD
21
22
23
24
25
26
27
28
4
3
2
1
0
51
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