Fridgewatch 2100 Controller Mk4
Section 3
Publication 3-58
Issue 1.1 : 01/08
Page 103 of 152
CAUTION
If a 4-way valve is used but S62 = 1 or 3 is set by
mistake, both solenoid valve coils will be energised at
the same time and will eventually burn out.
S63 P4 (4 to 20 mA analogue inputs): unused/type
The value assigned to S63 depends on the type of slide valve position
indication fitted to the compressor; refer to Table 13 and Table 14 and the
following notes. Note the application limitations in the footnote to Table
14.
The LVDT fitted to HallScrew 2000, 3100 new series, 3200 and 4200
series compressors, provides a 4 to 20 mA signal enabling P4 to indicate
the position of the compressor capacity slide valves.
The type of HBLVDT usually fitted to HallScrew 3100 new series, 3200
and 4200 series compressors provides a 4 to 20 mA signal but without
means of calibration on the LVDT. Calibration of P4 is done in
Fridgewatch software, i.e. Fridgewatch 2100 needs to be told when the
4 to 20 mA signal corresponds to minimum and maximum slide valve
position. This facility is provided by S63 setting 4 and the procedure
described in 12.5. Calibration of LVDT 4 to 20 mA Signal – HS 3100 New
Series, HS 3200 and HS 4200 Series Compressors.
Early HallScrew 2000 series compressors fitted with an LVDT or NLVD
and current 2000 series compressors fitted with a HBLVDT all have
calibration of the 4 to 20 mA signal provided on the LVDT. For these
compressors S63 can be set to 3.
NOTE: If S63 is set to 3 or 4, S98 and S99 must both be
set to 0.
HallScrew 2100 and 3100 old series compressors are not fitted with an
LVDT and, therefore, have no 4 to 20 mA signal to connect to P4 for slide
valve position indication. The three slide valve position reed switches
fitted for minimum, intermediate and maximum slide valve position must
be wired to terminals x29/x32 on the 3MIO1 and 3MIO2 cards; refer to
Fig 24 and Fig 26. For these compressors, without an LVDT, S63 cannot
be set 1 to 4.