Mega MEg40+, Manual

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Měřící Energetické Aparáty
16
5.1 installation of the instrument with the serial communication
rs485, rs232
The universal energy meter MEg40
+
can be installed also into networks with commu-
nication interface RS485 or RS232. The required communication interfaces must be
specified in the order.
The modulation rate of the communication interfaces RS485 and RS232 is 115.2 kBd.
No data transfer is possible at an increased rate with interruption of the measurement.
To interconnect, it is recommended to use a shielded twisted pair. The connection of
terminals for RS485 and RS232 communication is as follows:
INSTRUMENT MEg40
+
(direction from the instrument)
INTERFACE
RS485
INTERFACE
RS232
TxD (output) Rx+ or RxTx+ TxD
RxD (input) Rx− or RxTx− RxD
⊥
shielding
⊥
If it is necessary to additionally ensure remote communication with the instrument
MEg40
+
equipped with the USB 2.0 interface, it is possible to use the USBhost / RS485
converter to convert the USB 2.0 interface to the RS485 interface.
6/ oPEration oF thE instrUMEnt MEg40
+
Operation of the instrument MEg40
+
in the basic version includes programming the
measurement, reading the measured data of USB 2.0 communications, and taking out
the memory card with measured data and inserting an empty card if 16 MB memory
card is used.
The measurement is programmed in the instrument MEg40
+
using PC or PDA with the
running user program MEg40
+
when the PC or PDA are connected to the instrument
MEg40
+
through the communication cable MEg40
+
-PC, 1.8 m or 5 m long, with ferrite
absorbers. The procedure how to program measurements is included in the description of
the program MEg40
+
. After the function Recorder is programmed, the letter Z appears
permanently in the top R.H. corner, and after the function Registration of events is
programmed, the letter U appears permanently in the top R.H. corner of the display of
the instrument MEg40
+
.
It is possible to read the measured data through the serial communication USB 2.0 without
interrupting the measurement when the data are read into a data file in PC at the speed
of 115.2 kbit/sec. The measured data can be read into the data file also with interruption
of the running measurement, then the communication speed increases automatically to
256 kbit/sec and the communication is not interrupted due to the running measurement.