Siemens 7SR21 Manual page 69

Observation
Cannot communicate with the relay.
Relays will not communicate in a ring
network.
Status inputs do not work.
Relay instrument displays show small
currents or voltages even though the
system is dead.
If the above checklist does not help in correcting the problem please contact the local Siemens office or contact
PTD 24hr Customer Support, Tel: +49 180 524 7000, Fax: +49 180 524 2471, e-mail:
support.energy@siemens.com.
©2010 Siemens Protection Devices Limited
7SR21 & 7SR22 Argus Commissioning and Maintenance
Action
Check that all of the communications settings match those used
by Reydisp Evolution.
Check that the Tx and Rx fibre-optic cables are connected
correctly. (Tx –> Rx and Rx –> Tx).
Check that all cables, modems and fibre-optic cables work
correctly.
Ensure that IEC 60870-5-103 is specified for the connected port
(COM1, COM2, COM3 or COM4).
Check that the Data Echo setting on all relays is set to ON.
Check that all relays are powered up.
Check that all relays have unique addresses.
Check that the correct DC voltage is applied and that the polarity
is correct.
Check that the status input settings such as the pick-up and drop-
off timers and the status inversion function are correctly set.
This is normal. The relay is displaying calculation noise. This will
not affect any accuracy claims for the relay.
Chapter 6 Page 69 of 69