Serial Protocol Types; Modbus Slave - JUMO LOGOSCREEN nt Interface Description

5.1 Modbus slave

Modem
operation
If the JUMO Logoscreen nt has been configured as a slave (see Chapter 3.4
Configuration of the serial interfaces, page 12) it will respond to a Modbus
request from the master in the network.
The master controls the data exchange, the slaves only have a response
function. They are identified by their device addresses.
The master is usually a PC with a setup program or a visualization program.
The master can requests all the device variables of the JUMO Logoscreen nt
(see Chapter 7 Address tables, page 43).
In a Modbus network, only one device is allowed to take on the
master function!
- A Logoscreen nt in slave mode can be controlled by the master via a
modem over a telephone line, see the picture above.
- The paperless recorder can initialize a modem itself (also cyclically, for the
situation where the modem is switched on after the instrument).
- The recorder can use the INIT string (entry with the setup program in the
mask "RS232/RS485: Modem") to configure the modem so that it will
automatically accept ("pick up") an incoming call. The recorder can then be
remotely interrogated by the master, using Modbus commands, or send a
signal (e.g. an alarm) or an e-mail after active dial-up.
- Using a dial-up/hang-up string, the paperless recorder (slave) can send an
alarm to a PC (master) with the JUMO SVS-2000 software. The JUMO SVS-
2000 software detects incoming modem calls.
- Using a dial-up/hang-up string, the paperless recorder (slave) can also call
an Internet provider and send an e-mail.
When modem operation is active, the following parameters can be edited (only
through the setup program):

5 Serial protocol types

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