C0240111-04-05-GB
3.2 Connecting more than one unit
Caution:
perform the following operations before touching the cards in order to prevent
electrostatic discharge:
x
wear the bracelet (connected to the earth circuit) and the heel strap
x
the card should be closed inside an antistatic bag protecting it from electrostatic
discharge: remove it from the bag and place it on the light-blue mat with the yellow
edge or on the dark-blue mat.
x
You can now work on the card.
Several intercommunicating cards can be connected together on units “L” or “XL”.
There are two connection types: “base-expansion” on the expansion serial line and “master-slave” on the
“plan” serial line. The “mixed” connection, instead, combines the two above connections. Details are
shown below.
3.2.1 “BASE-EXPANSION” CONNECTION
In the “base-expansion” connection, the entire intelligence of the unit resides in the base. The connected
expansions are exclusively used as additional I/O. The cards must be connected together with a three-
wire shielded cable connected from terminal J23 of the base to terminal J3 of expansion “E” or to
terminal J11 of expansion “M” (see figure 3.1).
Figure 3.1:
“base-expansion” connection
The expansions must be given a specific address depending on the type of chiller and the enabled
functions:
EXPANSIONS FOR HERMETIC COMPRESSORS:
Additional function
Function, chiller type
Expansion
address
Expansion
type
Recovery enable
Chiller with heat recovery
1
E
Recovery enable
Multi-use
Heat pump with total heat recovery
2
M
Freecooling enable
HP relay enable
Low temperature control enable
Low pressure transducer enable
Freecooling chiller
Chiller with HP relay
Low temperature chiller
Any chiller with hermetic
compressors where low pressure
monitoring is required
3
E
9