Carrier 040-420 User Manual

Page 64

Control Modules

Turn controller power off before servicing controls. This
ensures safety and prevents damage to controller.

PROCESSOR MODULE

4 IN/4 OUT MODULE

(SIO), LOW-VOLTAGE

(DSIO), AND

EXV DRIVER MODULE (DSIO)

The PSIO, DSIO and

SIO modules all perform continuous diagnostic evaluations

of the condition of the hardware. Proper operation of these
modules is indicated by

(light emitting diodes) on the

front surface of the

and on the top horizontal sur-

face of the

and SIO.

RED LED Blinking continuously at a to

rate

indicates proper operation. Lighted continuously indicates

a problem requiring replacement of module. Off continu-
ously indicates power should be checked. If there is no in-
put power, check fuses. If fuse is bad, check for shorted
secondary of transformer or for bad module. On the
module, if the light is blinking at a rate of twice per sec-
ond, the module should be replaced.

GREEN LED On a

and an SIO, this is the green

LED closest to COMM connectors. The other green LED
on module indicates external communications, when used.
Green LED should always be blinking when power is on. It
indicates modules are communicating properly. If green LED

is not blinking, check red LED. If red LED is normal, check

module address switches. See Fig.

Proper addresses are:

(Processor Module)

01 (different when CCN

connected)

DSIO (Relay Module)

DSIO (EXV Driver Module)

(4 In/4 Out Module)

modules indicate communication failure, check COMM

plug on

module for proper seating. If a good connec-

tion is assured and condition persists, replace
module.

If only DSIO or

module indicates communication

failure, check COMM plug on that mode for proper seat-
ing. If a good connection is assured and condition persists,
replace DSIO or SIO module.

All system operating intelligence rests in

module ,

the module that controls unit. This module monitors con-
ditions through input and output ports and through DSIO
modules (low-voltage relay module and EXV driver
module).

The machine operator communicates with microproces-

sor through keypad and display module. Communication

between

and other modules is accomplished by a 3-wire

sensor bus. These 3 wires run in parallel from module to

module.

On sensor bus terminal strips, terminal 1 of

Module

Address

ule is connected to terminal 1 of each of the other modules.

Fig. 18
Selector Switch Locations

Terminals 2 and 3 are connected in the same manner. See
Fig, 19, If a terminal 2 wire is connected to terminal sys-
tem does not work.

II Chillers, processor module, low-voltage

relay module, and keypad and display module are all pow-
ered from a common

power source which connects

to terminals 1 and 2 of power input strip on each module. A

separate source of

power is used to power options

module through terminals 1 and 2 on power input strip. A
separate source of 12.5

power is used to power EXV

driver module through terminals 1 and 2 on power input

strip.

ADDRESS

SELECTOR