16.11
Date Code 20171006 Instruction Manual SEL-400 Series Relays
DNP3 Communication
DNP3 in the Relay
Modem Support
The relay DNP3 implementation includes modem support. Your DNP3 master
can dial-in to the relay and establish a DNP3 connection. The relay can automati-
cally dial out and deliver unsolicited DNP3 event data. When the relay dials out,
it waits for the CONNECT message from the local modem and for assertion of
the relay CTS line before continuing the DNP3 transaction. This requires a con-
nection from the modem DCD to the relay CTS line.
NOTE: Contact SEL for information
on serial cable configurations and
requirements for connecting your
relay to other devices.
Either connect the modem to a computer and configure it before connecting it to
the relay, or program the appropriate modem setup string in the modem startup
string setting MSTR. Use the PH_NUM1 setting to set the phone number that
you want the relay to dial. The relay will automatically send the ATDT modem
dial command and then the contents of the PH_NUM1 setting when dialing the
modem. PH_NUM1 is a text setting that must conform to the AT modem com-
mand set dialing string standard. Use a comma (,) for a pause of four seconds.
You may need to include a nine to reach an outside line or a one if the number
requires long distance access. You can also insert other special codes your tele-
phone service provider designates for block call waiting and other telephone line
features.
The relay supports backup dial-out to a second phone number. If PH_NUM2 is
set, the RETRY1 setting is used to configure the number of times the relay tries
to dial PH_NUM1 before dialing PH_NUM2. Similarly, the RETRY2 setting
configures the number of times the relay tries to dial PH_NUM2 before trying
PH_NUM1. MDTIME sets the length of time from initiating the call to declaring
it failed because of no connection, and MDRET sets the time between dial-out
attempts.
DNP3 Settings
DNP3 configuration involves both Global (SET G) and Port (SET P) settings.
The Global settings govern behavior for all DNP3 sessions, serial or LAN/WAN.
The Port settings apply to specific DNP3 sessions only.
There are two Global settings that directly configure DNP3. These settings, EVE-
LOCK and DNPSRC, define the behavior of Fault Summary event retrieval and
the DNP3 session time base. See Reading Relay Event Data on page 16.21 for
more information on EVELOCK. The DNPSRC setting can be either LOCAL or
UTC (default). See Time Synchronization on page 16.10 for more information on
the DNPSRC setting.
The DNP3 protocol settings are shown in Table 12.16 on page 12.10 and
Table 12.17 on page 12.11. The DNP3 protocol settings are in the port settings
for the port that you select for the DNP3 protocol. You can use DNP3 on any of
the serial ports (PORT F and PORT 1–PORT 3) or Ethernet port (PORT 5), but
you can only enable DNP3 on one serial port at a time. You may enable as many
as six DNP3 sessions on the Ethernet port, independent of the number of serial
DNP3 sessions enabled.
Warm Start and Cold Start
The DNP3 function codes for warm start and cold start reset the relay serial port
or DNP3 Ethernet session. These function codes do not interrupt protection pro-
cesses within the relay.
NOTE: RTS/CTS hardware flow
control is not available for a DNP3
modem connection. You must set the
port data speed slower than the
effective data rate of the modem.
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