15
MLV/Condenser Board —
One auxiliary board is op-
tionally installed in each unit. See Fig. 11. The auxiliary board
contains an analog output for head pressure control and dis-
crete outputs for minimum load control. The auxiliary board
responds to commands from the MBB and sends the MBB the
results of the channels it monitors via the Local Equipment
Network (LEN). See below for auxiliary board A, B and C DIP
switch addresses. See Table 8 for inputs and outputs.
Table 8 — Auxiliary Board Outputs
AUX BOARD
DIP SWITCH
1
2
3
4
5
6
7
8
Address:
OFF
ON
OFF
OFF
ON
OFF
ON
OFF
DESCRIPTION
INPUT/OUTPUT
I/O TYPE
DISPLAY MODULE POINT NAME
CONNECTION POINT
Pin
Notation
Power (24 vac supply)
—
—
—
AUX-J1
11
24 vac
12
Ground
Local Equipment Network
—
—
—
AUX-J9
+
RS485 Port (D+)
G
RS485 Port (Gnd)
-
RS485 Port (D-)
+
RS485 Port (D+)
G
RS485 Port (Gnd)
-
RS485 Port (D-)
Condenser Head Pressure Control
Speed Signal
HD_A
0-10 VDC
Head Press Actuator Pos,
SPD.A
AUX-CH9
+
Signal
-
Ground
Minimum Load Valve A
MLV-A
Solenoid
Minimum Load Valve Circuit A,
MLV.A
AUX-J2-CH3
Minimum Load Valve B
MLV-B
Solenoid
Minimum Load Valve Circuit B,
MLV.B
AUX-J2-CH4
1
2
3
4
5
6
7
8
ON
100K
100K
100K
CH1
CH2
CH
3
CH4
CH5
CH6
CH7
CH
8
TR1
TR2
TR
3
TR4
TR5
TR6
TR7
TR
8
S
TATU
S
S
IO (LEN)
LOCATION OF
S
ERIAL NUMBER
24 V
A
C
CH1
3
CH14
J9
J1
CH9
CH10
CH11
CH12
JP2
C61
CH1
3
D12
JP1
L
3
L5
U21
L2
D6
D5
Q5
Y1
D7
D
8
S
1
D
3
U1
Q1
U5
U6
U7
U
8
U9
Q10
Q11
U10
J4
J
3
J2
U4
U2
Q12
Q60
3
2 1
– G +
3
2 1
– G +
DIP
S
WITCH
Fig. 11 — Auxiliary Board with Optional Minimum Load Control or Head Pressure Control
a30-4046