Acl Timers - Comtec CDM-840 Installation And Operation Manual

CDM-840 Remote Router
Appendix M
When you disable DPC, the CDM-840 notifies the CDD-880 and modifies the timer check logic,
changing the target window to E
for this change is, with DPC disabled, the power level is set to Current Power+Margin Moving
Power>Target Power; if not changed, the timer would be at fast rate indefinitely. This change
also allows ACM to operate normally without DPC.
M.2.3.1.2

ACL Timers

Timers on both sides on the link are required to maintain quality and reduce hysteresis, with
each end having a specific and separate function:
•
CDD-880 Messaging Timers – CDD-880 timers are state-driven on when to send the next
LQRM:
o Every 500 ms, send E
Unlocked, E

o Every 60 seconds, send E
Locked, E

•
CDM-840 Power Adjustment Timers – CDM-840 timers are dependent on receipt or loss of
LQRM:
o Targeting Power adjustment (ratcheted steps)
.3 dB every 100 ms steps >1 dB

.1 dB targeting steps <1 dB

o Timeout on 60-second intervals
Two consecutive missed messages, 120 seconds

 Drop to BPSK, go to rated max power
Four consecutive missed messages, 240 seconds

 Recovery Mode, loss of LQRM, remove
 Stay at BPSK until next LQRM
/N below .5 dB and/or ModCod is not at maximum. The reason
S 0
/N data
S 0
/N outside target window or max ModCod mismatch.
S 0
/N data, keep-alive
S 0
/N = Target (target window ±.5 dB)
S 0
M–10
demod from active control list
MN-CDM840
Revision 3