Parker Hannifin S.p.A. - Divisione S.B.C. LVD User’s Manual
85
Broadcast message to write a parameter from Master to LVD
Broadcast data write
Data length
7 bytes
Field Name
Cmd & Len
Data Address
Data
Contents
5 bit command and 3 bit length
16 bit data address
32 bit data
Identifier
ID2
ID1
ID0
-
-
-
-
-
ID10 ID9
ID8
ID7
ID6
ID5
ID4
ID3
1
1
1
X
X
X
X
X
0
0
1
0
0
0
1
1
Data
In the case of parameter writing, this portion contains the value of the
parameter.
In the case of modification of one or more bits, contains the mask of the bits to
be modified.
Data Address This is the address of the parameter involved in the operation (see the table in
the heading
Serial addresses and parameter lengths
).
Cmd & Len
Sub-field
Value
Significance
Cmd [0..4]
0
not used
1
Write
2
SET bit Pr = Pr .OR. Data
3
RESET bit Pr = Pr .AND. (.NOT.Data)
4
TOGGLE bit Pr = Pr .XOR. Data
5 - 31
not used
Len [5..7]
0- 4
Number of significant bytes in Data field
Alarm message from LVD to Master
Error
Data length
3 bytes
Field Name
Addr
Error
Contents
Pr27+1
Pr23
Identifier
ID2
ID1
ID0
-
-
-
-
-
ID10 ID9
ID8
ID7
ID6
ID5
ID4
ID3
A2
A1
A0
X
X
X
X
X
0
0
0
1
0
0
0
A3
A0:A4
Slave LVD address (Pr27+1), valid values 1..15.
If the Drive enters alarm status it will transmit this message on the bus.
To calculate the minimum sampling time, use the formula:
Tc
min
= ( Nr + Nt + 5 ) * 0.12
where: Tc
min
is minimum sampling time in msecs
Nr is the number of LVDs that receive the reference
Nt is the number of LVDs that transmit the feedback signal
Typical SBCCAN timing in real time mode is shown in the figure on the next page.