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Universal Measuring Device UMG 500A
PC or similar
with RS-232-
Interface
○
○
○
RS485
RS232
(V24)
Interface
converter
UMG
Station 1
UMG
Station n
UMG
Station 3
UMG
Station 2
Serial interface
Universal Measuring Device UMG 500A is fitted with an
RS-485 serial interface. This enables up to 32 Universal
Measuring Devices to be driven on a common bus with a
total length of up to 1000 m. With the aid of a communi-
cations protocol, measurement data can be read from each
connected UMG and setting data (e.g. current transformer)
can be transmitted to each UMG.
Figure: Connection example for serial interface
Connection PC to interface converter
The interface converter can be plugged in directly to the
COM port of a PC (25-pin plug) via the adapter provided
(socket-socket).
Great care must be taken to ensure that the
parallel port of the PC (25-pin socket) is not
used, because otherwise damage to the device
can occur.
Alternatively, a connecting cable (25-pin, socket-socket)
can be used instead of the adapter. This cable must not be
longer than 5 m.
The RJ-11 socket of the interface remains unused.
Communication parameters
The following transmission parameters are permanently
set on the UMG 500A:
baud rate
9600 bd
data bits
8
parity
N
stop bits
1
These parameters must also be set at the PC, e.g. using the
DOS command:
mode com1:9600,n,8,1
Bus connection
All measuring stations (UMG 500 A) are connected with
one another via a four-core screened cable and to the 4-pin
terminal strip of the interface converter, whereby the
screening is not connected. The pin assignment is given in
the following plan:
UMG(s)
Converter
Recommended cable type: JY(St)Y 2 x 2 x 0.6 or similar.
Maximum cable length: 1000 m.
16
15
14
13
1
2
3
4
RxD A
RxD B
TxD A
TxD B
