Group Volume Increment command (SH) does not function correctly with volume at -inf

The Group Volume Increment (SH) serial command does not operate correctly when the Group Volume reaches -inf. The situation can arise when the same Group Volume is assigned to a user interface (eg. CC-64/CC-16) and is also controlled externally (eg. AMX/Crestron). If the external controller is only using the Group Increment/Decrement command (SH) it can become ‘locked out’ and unable to increase the Group Volume.

The serial protocol was defined with a minimum level of -60dB whereas the user interfaces also support the -inf level. If the user adjusts the Group Volume to -inf (displayed as -999.0 dB on the CC-64) the Group Volume Increment command cannot then raise the level. Additionally a Group Volume at -inf will return the same value as one at -60dB (value=0) when using the Get Group Volume (GG) command making it harder to differentiate between the two conditions.

ESP-88 (v2.042 or later)

Whenever the Group volume reaches value=0 issuing a Set Group Volume (SG) command with the value=0 will force the Group level to -60dB whether it’s at -60dB or -inf thus ensuring the Group Volume Increment command can function correctly.

Note that this will cause a visual change for the user on the CC-64, the displayed level of -999.0 dB will change to -60 dB once reset.

Issue resolved - ESP-88/00 (v3.040 or later)