Technical data

MESOMATIC Automation und Messtechnik GmbH D-71394 Kernen
4.4.2. Bidirectional channel (identifier 0xFF)
The bidirectional (acyclic) channel allows to transmit to and receive from the DK900
commands and/or data, via the Profibus.
Commands and/or data ® DK900
Master DK900 (slave) Explanation
!0
(ACK/NAK)
Settting zero
!B
(ACK/NAK)
Gross
!N
(ACK/NAK)
Net (taring)
!R
(ACK/NAK)
Reset
!A abcd
(ACK/NAK)
Set / reset outputs
Table 2a Summary of the serial functions available
The command:
!A m abcd
is for set / reset the outputs.
If m=1 (31Hex), the digital outputs (A0 ... A5) can be set.
a always 0 (30Hex)
b always 0 (30Hex)
c = Required status for output A5 + A4
2
7
= 0 / 2
6
= 0 / 2
5
= 1 / 2
4
= 1/ 2
3
= 0 / 2
2
= 0
2
1
= Output A5
2
0
= Output A4
d = Required status for output A3...A0
2
7
= 0 / 2
6
= 0 / 2
5
= 1 / 2
4
= 1
2
3
= Output A3
2
2
= Output A2
2
1
= Output A1
2
0
= Output A0
If m=3, (33Hex), individual Bits of the outputs A0...A5 can be set separately or reset.
a = 0 (30Hex) reset individual bit
= 1 (31Hex) set individual bit
b = always 0 (30Hex)
c = always 0 (30Hex)
d = 30Hex Output 0
31Hex Output 1
32Hex Output 2
33Hex Output 3
34Hex Output 4
35Hex Output 5
Data ¬ DK900
Master DK900 (slave) Explanation
*I
viiiiiinxxxxxxxx Request the actual value
(gross/net)
v = sign
iiiiii = actual value
n = No. of digits after the
decimal point
xxxxxxxx = free
Table 2b Summary of the serial functions available
The toggle bit must be changed in order to trigger transmission. A new transmission is
started as soon as the toggle bit has changed from 0 to 1 or vica versa. The response is
invalid unless the toggle bit received has the same state as the request. The Master must,
therefore, wait for the DK900’s response until it can transmit a new command (data request)
to the DK900. “Acknowledge” is set when the response to a telegram without data response
was ACK, or data were delivered in response to a telegram with data response.
The response time to commands which read or write data amounts to appr. 10 milliseconds.
Commands which cause a response of the DK900 (e. g. tare) have an execution time of 0.3 to
2 seconds at maximum (depending on, among others, the mean value rate parameterised).
Therefore, the response to such commands cannot appear on the Profibus before this time has
elapsed.
DK900 14