Grundfos CIU 250, Instructions Manual

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6. GSM call-up connection to SCADA system
6.1 Call-up functional description
The call-up function is used for SCADA system communication
via the GSM network. Connection is established when the
SCADA system dials the CIU 250. The CIU 250 will automatically
"pick up the phone call" and wait for data traffic in the form of
Modbus RTU telegrams.
If legal data traffic has not been initiated within one minute,
the CIU 250 will hang up the line. This silence timeout is active
during the whole communication session. Whenever the SCADA
system has completed the Modbus communication, it hangs up
the line. This is detected by the CIU 250, which also hangs up the
line, and the call-up communication session is thereby
completed. See fig.
7 .
Fig. 7
Illustration of a GSM call-up session
6.2 SCADA PIN code protection
It is always possible to get read access via Modbus, but if the
CIU 250 is SCADA PIN-code-protected (GeneralStatus register
00029, bit 0 = 1), write access requires that the correct PIN code
(ScadaPinCode, register 00011) has been written. Writing the
correct PIN code value will trigger the write access control, and
write access will be open, which can be verified with
GeneralStatus, register 00029, bit 1 = 1).
For call-up connections with PIN code protection, the
ScadaPinCode register has to be written each time a new call-up
is made.
6.3 GSM call-up options setup
To prepare the CIU 250 for Modbus communication with a
SCADA system via GSM, some settings have to be made via
SMS commands:
• Setting a SCADA PIN code:
SETSCADACODE <access code>
will enable write access protection.
Default is an empty SCADA PIN code, meaning no protection.
• Activating the SCADA PIN code:
SCADACODE <ON | OFF>.
Default is "Off".
• Selecting the Modbus address:
MODBUSADDR <1-247>
Default value is 231.
To verify the SCADA GSM setting after completion, the SMS
command "SCADA" can be used.
For details about the use of SMS commands, see "CIM 25X SMS
commands" (supplement to installation and operating
instructions) on the CD-ROM supplied with the GSM module.
TM
04
49
05
22
09
Dialling
Connection established
Hang-up
Modbus communication
Silence timeout after 1 min
without communication
GSM network
(e.g. SCADA)
CIU 250
Hangs up
the line.
Hangs up
the line.
Session
completed.