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| Operation & Maintenance Instructions TOPAX L1/L4/L5 | Data Readout
7.1 Current output
You can read out the measurement vales as a 0/4-20 mA signal over the current output.
By setting the 4-20 mA signal, resolution is indeed lost; defective cable connections are,
however, immediately recognizable.
With the start value and end value parameters, you can decide which section of the mea-
surement range you register over the current output.
As an alternative, you can also use the current output as a permanent register output and
assign the actuating variable of S1 or S2. In this case, the start and end values should not
be taken into account.
7. RS485 Serial interface (optional)
The devices can be supplied with an optional RS485 interface for data bus integration. The
interface does allow for readout of all data and settings. All information for the communi-
cation is available on request.
7.3 Assembly of a Data Network (TopView).
With the (optional) RS 485 computer interface it is possible to transfer data to a PC. Fur-
thermore multiple TOPAX L/LFs can be connected to a network. Each TOPAX L/LF (with
RS 485) has to be allocated an address for this purpose.
The maximum length of data transfer amounts to 1000 m. Up to 14 TOPAX L/LFs can be
connected with a PC to a network. The data line has to be attached directly to the TOPAX
L/LF’s RS 485 terminal:
Casing
Connection
Allocation
wall assembly
terminal
18
+
A
17
-
B
mounting
sub-D
3
+
A
8
-
B
CAUTION!
Separate connection sockets or junction boxes within the data line have to be
avoided. One must use a cable type “KAT.5, XXAWG4/1 (Lapp cable) or better.
The manufacturer is not liable for this.
Due to electromagnetic compatibility the cable’s screen has to be connected on both sides
before the device connections large surface area and conduct well with the protective
earth. For this it has to be confirmed that no potential current loss can escape over the
screen.
Today’s computers are equipped with a serial computer interface RS 232 (9-pin Sub-D
connector) and/or with a USB-connector. In this case an additional connector converter
has to be inserted in the PC (RS 485 to RS 232 or RS 485 to USB).
10 ohm cut-off resistances.
At both ends of the network the data line has to be cut off with a resistance of 120 ohm.
It is possible to put the switch for the resistance on the last TOPAX L/LF in the network
