Fridgewatch 2100 Controller Mk4
Publication 3-58
Section 3
Page 36 of 152
Issue 1.1 : 01/08
T
RANSDUCER
A
B
C
P1 Temperature
No 1 Set Point
No 2 Set Point
No 1 Start Value
No 2 Start Value
No 1 Stop Value
No 2 Stop Value
P2 Pressure
or
1
Temperature
No 1 Set Point
No 2 Set Point
No 1 Start Value
No 2 Start Value
No 1 Stop Value
No 2 Stop Value
Select Any One Box From Column A, One From B and One From C. Other Permutations are NOT Permitted.
1
Hardware modification are required if this input is used for connecting a second temperature transducer; refer to Table 2.
Table 3 Rule for Selecting Controlling Parameters for Two Start Value/Set Point/Stop Value Sets
When two start value/set point/stop value sets are used, either
temperature or pressure can be used as the controlling parameter, or a
combination of both types; for example, start on temperature, stop on
pressure, control on temperature. However, different parameters cannot
be used for the same types of control variable. For example, No 1 and
No 2 start values can both be temperature or pressure, but it is not
possible to use temperature for No 1 start value and pressure for No 2
start value. This important rule is illustrated in Table 3.
6.1.2. Digital
Outputs
Fig 18 and Fig 19 illustrate the usual application for each digital output.
However, if any digital output is
NOT
used for the purpose illustrated, it
may be used for a different purpose provided the indicated behaviour is
suitable for that purpose.
6.2. Installing
Transducers
It is essential to select transducers with physical characteristics within the
design maximum and minimum operating conditions. For pressure
transducers, the pressure range is clearly marked on the transducer; no
adjustment is provided. Transducers must conform to the parameters
defined in Table 10.
Pressure transducers can be teed into pressure gauge lines as shown in
Fig 10; an isolating valve must be fitted. Pipe runs should be routed to
prevent oil logging.
Temperature transducers can be supplied for tank or pipe mounting as
shown in Fig 10.
If transducer wiring is not long enough to reach the Fridgewatch 2100
panel, intermediate connections using local terminals boxes may be
necessary.
6.3.
Using Fridgewatch 2100 to Drive Relays
The Fridgewatch 2100 compressor and auxiliary start signals must only
be used to drive a low consumption 24 V dc relay (40 mA maximum);
these relays are usually located in the starter panel. The volt-free
contacts on the relay should be used to switch the starter contactors. A
suggested low consumption relay would be an Omron LY2 (RS
Components part number 329-799).
