FOCUS 1.6 Functions
Page 26 BOGE FOCUS compressor control for piston compressors
In case of cyclic operation use Parameter P071 to set the cycle time. For this
reason, the switch clock must either not be used (no weekday on any channel)
or, in case of any other type of use, no priority sequence must be contained in
the respective switch clock channel (nor the sequence 0000, but only – – – –)!
When using the switch clock for base load switching purposes, parameter
P071 has to be set at zero! 26 switch clock channels (switch points) are avail-
able. Entering a weekday causes a channel to be activated. Any priority se-
quence is available for selection. In addition, shut-off is possible by using the
0000 priority sequence.
Selection of the second pressure band by means of the switch clock allows
temporary change to a lower pressure range.
Furthermore, the switch clock is equipped with a potential free change-over
contact.
As of version 1.18 the base load switching control normally uses the pressure
value of parameter P075 as the upper shut-off value and of parameter P076
as the lower switch-on value. All other necessary shut-off and switch-on pres-
sure values are automatically calculated.
The proper internal pressure switch points of the connected compressors are
to be selected such as to prevent such compressors from switching them-
selves off within the pressure band as set at the master unit. In this conjunc-
tion, possible pressure pipe losses are to be taken into account. In case of
installations with system pressure transmitter this applies also for compressor
1 (Master).
If pressure reduction (parameter P077 is used as upper nominal pressure
value, parameter P078 as lower value as of version 1.18) is applied, all other
FOCUS controls using the RS485 interface for connection to the master unit
will automatically be switched to their second pressure band.
In this conjunction, make sure not to use the digital input "Pressure Band" of
the slave compressors and that their switch clocks do not impact on their pres-
sure band:
Example with monitoring and emergency operation function
Four compressors (145 psi), all of which are equipped with a FOCUS control,
are connected by means of RS485 interfaces. Pressure at user's facility must
not completely be shut off, should however be able to be reduced. Providing
sufficient receiver / network volume, the pressure values can be set according
to the following table allowing pressure reduction by 22 psi which can be ac-
tuated by an external contact or by means of a switch clock – as regards switch
clock actuated pressure reduction, also see chapter Unplanned compressed
air requirement.
Compressor Parameter setting in psi
No P075 P076 P077 P078 P012 P013 P014 P015 P064
1 (Master) 137.8 108.8 116 87 145 107 123 86 1
2 144 106 122 84 1
3 no function 142 104 120 83 1
4 141 103 119 81 1
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