Johnson Controls SABROE Unisab III Control, Engineering Manual

Page: 135 / 348

Engineering manual - UniSAB III 1.10.8
001930 en 2021.06
135/346
Compressor control and surveillance
When the compressor is equipped with VSD and the soft Centa coupling one of the following unloading
functions must be chosen:
• VSD normal – see subsection 6.4.3 Compressor block .
• VSD total – see subsection 6.4.3 Compressor block .
Additional unloading is not available with Centa coupling.
Table 29 shows SMC VSD cylinder unloading with the Centa coupling. Percentages shown are the ca-
pacity at maximum speed.
Cylinders 2 4 6 8 10 12 14 16
Compressor
SMC/HPC 104
HPX 704
Digital output
DO09
100%
1
DO10
SMC/HPC 106
HPX 706
Digital output
DO09 DO10
100%
1
DO11
SMC/HPC 108
HPX 708
Digital output
DO09
50%
2
DO10
TPV (1)
DO11
100%
1+2
+DO12
TSMC 108
Digital output
-
33%
2
DO09
DO10
100%
1+2
+DO11
SMC/HPC 112
HPX 712
Digital output
- DO9
50%
2
DO10
TPV (1)
DO11 DO12
100%
1+2
+DO13
SMC/HPC 116
HPX 716
Digital output
-
25%
4
DO09
DO10
50%
3+4
+DO11
TPV
(1+2)
DO12
75%
2+3+4
+DO13
DO14
100%
1+2+3+4
+DO15
TSMC 116 *)
Digital output
-
17%
4
DO09
-
50%
3+4
+DO10
-
67%
2+3+4
TPV
(2HP)
+DO11
DO12
100%
1+2+3+4
+DO13
Table 29: SMC VSD cylinder unloading configuration with Centa coupling
The digital output and solenoid valves which must be activated to provide capacity control are emphas-
ised with
bold letters.
The Thermo Pump TPV connection for the high cylinder part is also shown in Table 29. The TPV con-
nection has not been changed - it is the same as for the standard compressor.
*) Note that on a standard TSMC 116 compressor, output DO09 will correspond to 33% (4+2 cylinders).
With VSD unloading, DO09 will correspond to 17% (2+2 cylinders).