Leuze electronic GmbH + Co. KG
MA 238
i
37
Bits of the input byte (status byte) 1
10.2.2 Detailed description of the bits (input byte 0)
Bit 0: Write-Acknowledge: W-ACK
This bit is only relevant for writing slave data in blocks, see Chapter 11.1.2 (buffer data on RS 232). It
toggles when data from the PLC are sent to the MA with CTB or SFB.
Bit 2: Service Mode Active: SMA
Bit 3: Data exist: DEX
This bit is only relevant for reading slave data in Collective mode, see Chapter 11.1.1.
Bit 4: Next block ready to transmit: BLR
This bit is only relevant for reading slave data in Collective mode, see Chapter 11.1.1.
4
BLR
Next block ready (new block ready)
5
DL
Data loss
6
BO
Buffer overflow
7
ND
New data only in Transparent mode
Bit no.
Designation
Meaning
0 … 7
DLC0 … DLC7
Data Length Code (length of the following user data)
NOTE
T-bit means toggle bit, i.e. this bit changes its state on each event ("0"
p
"1" or "1"
p
"0").
Bit no.
Designation
Meaning
Input data
Description
Addr.
Data
type
Value range
Default
W-ACK
Write-Acknowledge
(write confirmation)
Write handshake
Indicates that the data was successfully sent by the PLC
to the gateway.
Write-Acknowledge is indicated via this bit. The W-ACK
bit is toggled by the fieldbus gateway whenever a trans
-
mit command has been successfully executed. This
applies both for the transmission of data to the transmit
buffer with the CTB command and for sending the trans
-
mission buffer contents with the SFB command.
0.0
Bit
0->1: Successfully writ
-
ten
1->0: Successfully writ
-
ten
0
Input data
Description
Addr.
Data
type
Value range
Default
SMA
Service Mode Active (SMA)
The SMA bit is set if the service switch is set to "MA" or
"DEV", i.e. if the device is in either fieldbus gateway or
Leuze device service mode. This is also indicated by a
flashing PWR LED on the front side of the device. Upon
changing to the normal operating mode "RUN", the bit
is reset.
0.2
Bit
0: Device in operating
mode
1: Device in service
mode
0h
Input data
Description
Addr.
Data
type
Value range
Default
DEX
Data exist
(data in transmission buffer)
Indicates that further data is stored in the transmission
buffer which is ready for transmission to the control. This
flag bit is always set to high ("1") by the fieldbus gateway
as long as data is in the buffer.
0.3
Bit
0: No data in the trans
-
mission buffer
1: Further data in the
transmission buffer
0h