janitza UMG 500 A, Руководство по эксплуатации

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Page 14
Universal Measuring Device UMG 500A
→ →
→ → →
ON
Value
S8 128
S7 64
S6 32
S5 16
S4 8
S3 4
S2 2
S1 1
S4 = ON 8
+
S1 = ON 1
=
Address 9
Setting the device address
The device address is set via an 8-fold DIP switch, which
can be reached through a cutaway on the left hand side of
the device. Addresses from 0 to 255 can be set.
The switches are marked with the numbers 1 to 8. An
arrow symbol, marked with ON, indicates the position of
the switch.
These switches S1 to S8 are coded in the DUAL SYSTEM,
i.e. each switch has double the value of the previous one
(1-2-4-16-32-64 etc.).
Figure: Example shows address 9
The position of the switches can be changed as required
using a ballpoint pen or narrow tweezers.
Do not use a pencil for this adjustment, because the lead
can break off and cause a short circuit.
Communication protocol
The communication protocol enables communication to
take place between the host system (the PC) and the
measuring stations using the master-slave principle, i.e.
the measuring stations never transmit independently, only
after being called up by the host system. The protocol
consists essentially of control characters for beginning
and end of protocol, the device address of the selected
measuring station, start address and content of desired data
and an end of protocol or acknowledge character. It does
not use a handshake signal.
All UMGs which are connected on the bus receive the data
transmitted from the PC. As soon as the device address has
been transmitted, the relevant device starts to answer the
message in relation to the required operating mode. The
other stations remain passive.
Note: Only stations with different device addresses can be
driven from a bus.
A message is only evaluated by the UMG after complete
and error-free transmission. The UMG breaks off the
connection if it does not receive further characters after
120 ms.
Dimensions
Device address
Copyright
© Janitza electronic GmbH 1995, 1996
This handbook may not be copied or reproduced by any means in whole or in part without the written permission of
Janitza.
(Dimensions in mm)