Technical data

58
Manual – MOVI-PLC® advanced DH.41B Controller
5
Parameter setting via PROFIBUS-DP
Operating Characteristics on PROFIBUS-DP
The following table shows how a write service is coded in management byte 0. The data
length for all parameters in the MOVI-PLC
®
advanced DHF41B control card is four
bytes. This service is now transferred to the MOVI-PLC
®
advanced DHF41B control
card when the handshake bit changes. Consequently, a write service on the
MOVI-PLC
®
advanced DHF41B control card always has the management byte coding
32hex or 72hex.
Parameter setting
sequence with
PROFIBUS-DP
Taking the example of the write service, the following table shows the parameter setting
sequence between higher-level controller and MOVI-PLC
®
advanced DHF41B control
card via PROFIBUS-DP. To simplify the sequence, only the management byte of the
parameter channel is shown here.
While the higher-level controller prepares the parameter channel for the write service,
the parameter channel is only received and returned by the MOVI-PLC
®
advanced
DHF41B control card. The service is not activated until the moment the handshake bit
is changed (in this example, when it changes from 0 to 1). The MOVI-PLC
®
advanced
DHF41B control card now interrupts the parameter channel and processes the write
service. However, it continues to respond to all telegrams with handshake bit = 0.
The executed service is acknowledged with a change of the handshake bit in the
response message of the MOVI-PLC
®
advanced DHF41B control card. The higher-level
controller now detects that the received handshake bit is the same as the one that was
sent. It can now prepare another parameter setting procedure.
7 / MSB 6 5 4 3 2 1 0 / LSB
00/1
1)
1) Bit value is changed
110010
Service identifier
0010 = Write parameter
Data length
11 = 4 bytes
Handshake bit
Must be changed on every new task in cyclical transmission.
Status bit
0 = No error during execution of service
1 = Error during execution of service
Control PROFIBUS-DP(V0) MOVI-PLC
®
advanced DHF41B
control card (slave)
-- 00110010XXX... →
Parameter channel is received, but
not evaluated
← 00110010XXX... --
Parameter channel is
prepared for the write
service
Handshake bit is
changed and the service
is transferred to the
MOVI-PLC
®
DHF41B
control card -- 01110010XXX... →
← 00110010XXX... --
-- 01110010XXX... →
← 00110010XXX... -- Write service is performed, hand-
shake bit is changed
Service confirmation is
received as the send
and receive handshake
bits are the same again
← 01110010XXX... --
-- 01110010XXX... → Parameter channel is received, but
not evaluated
00
I