MODEM COMMUNICATION TO ABB RELAYS
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Figure 47. Hyperterminal Screen for Data Communication Entry
Steps 6 and 7 – Configuration of the Modem Parameters for the Local and Remote
Sites
The US Robotics modems used (Model 002806- V.Everything) have commands similar to those of the
previous US Robotic modems. Several differences are apparent with respect to their “S” register
configurations and auto configurability. Additional sessions may be set up to allow remote configuration.
However, it is strongly advised that remote configuration and automation dial up capabilities not be used
with the REL512 since difficulties may result since handshaking is not available.
Another word of caution should be issued in that the V.Everything modem may experience difficulties
connecting with the REL512 master/slave emulation of the port during dial-up sessions. If the MODEM is
undergoing the attachment process and the REL 512 happens to send out its time ASCII string to the
MODEM simultaneously, the modem will disconnect and display the prompt “NO CARRIER” at the host
site. This process will take a few minutes to occur and until this occurs, no communications will occur. If
a command string is sensed via the SD line (remote modem LED will illumintate) during the dialing
process, the remote modem will hang up (the remote modem OH [On Hook] ) LED will extinguish. There
is no way to overcome this limitation in operation with this model of modem.
Some important words covering the configuration of the MODEM when used with the REL512:
•
DISABLE DTR (&D0)
•
USE THE DEFAULT DISABLE OF SOFTWARE FLOW CONTROL (&I0)
•
DSR ALWAYS ON (&S0)
•
DISABLE CARRIER DETECT (&C0)
•
Thus the command string should look like this:
AT&D0&S0&I0&C0&W
Note the &W writes the current setting to the Non-Volatile RAM.
Additional tips are covered in the following tips for LOCAL modem configuration (that modem attached to
the HYPERTERMINAL Personal Computer) and the REMOTE modem (that modem attached to the
Summary of Contents for REL 356
Page 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Page 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Page 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
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