Power Line Carrier ____________________________________________________________________
RF-MCGARDPRO
Hubbell Power Systems, Inc.
–
RFL™
Products
July 1, 2022
©2022 Hubbell Incorporated
5-5
Table 5-3 On/Off Block Transport Delay and Channel Spacing
Configuration Settings
Nominal Block
Transport Delay
Minimum Permissible
Channel Spacing
Nominal Receive Bandwidth: 500 Hz
5 ms
1 kHz
Nominal Receive Bandwidth: 1000 Hz
3 ms
2 kHz
Nominal Receive Bandwidth: 1500 Hz
1.5 ms
3 kHz
Security & Dependability do not really apply to an On/Off unit. The unit should issue a block
received output any time there is enough energy in the receive band regardless of total SNR.
Instead of security, adjacent channel rejection is probably more relevant. Dependability of an
On/Off unit should remain constant as noise increases until the input circuits (or DSP numbers)
saturate.
5.1.3 Compatibility Issues for PLC Module Software
For users of older GARD Systems:
The PLC Module Software is used with the GARD Custom System Logic to meet each user’s
specific application needs. The PLC Module Logic and HPS/RFL GARD Pro system PLC
System Logic were updated and both logic versions need to agree.
Beginning in October 2011, new PLC software (indicated as V17) was released to improve the
functionality of the unit. Although these changes are transparent to the end user, certain
compatibility issues with the new PLC software and older System Logic should be noted.
Units shipped after October 2011 have updated default PLC System Logic, however if GARD
units are modified in the field and have either new PLC software with old PLC System Logic or
the reverse, the units may not perform as expected. The two scenarios are described below:
Table 5-4. Compatibility Issues for PLC Module Software
New PLC software/Old system logic
New System Logic/Old PLC software
The function to disable the Transmitter from an external input will not function.
The security against unwanted operations
in FSK mode will be slightly reduced.
The unblocking feature in FSK will not
work.
The RX SNR alarm will not work.
Because of these differences, care must be taken when swapping modules or reusing the “Whole
Chassis Configuration” files from different versions.
The following is invalid:
•
Transferring existing PLC Digital Modules with V13 software (or earlier) into
units with updated System PLC Logic (V17 software).
•
Transferring new PLC Digital Modules (V17 software) into existing units with
previous System PLC Logic revision, other than V17.
