Remote Processing CX-10 - Manual (Page 26)

RELAY AND OPTO INPUT LINES SECTION 6
Page 6-1
Relay 7 Relay 8
A B C
P2
Figure 6-1 Relay group 1designations
Relay 5 Relay 6
D E F
P1
Figure 6-2 Relay group 2 designations
INTRODUCTION
RELAY AND OPTO INPUT LINES SECTION 6
The CX-10 has 8 relays organized into 3 groups. There
are also 8 optically buffered inputs.
Modbus registers 1 and 10-26 are used to access these
lines.
ELECTRICAL CHARACTERISTICS
Relays
All relays are normally open. They are closed when the
appropriate register for a relay has a “1" written to it. An
LED behind the relay lights up when it is energized.
Relays are rated for resistive load of 3 amperes at
125VAC or 30V DC. Minimum load is 10 milli-amperes
at 5V (dry circuit).
If you will be switching inductive circuits (such as
relays, contactors, or motors), then a transient absorber
should be placed across the relay contacts at P1 and P2.
Transient absorbers vary by voltage (AC or DC) and
power rating. Below is a table of possible transient
absorbers that may be used. These parts are available at
Digikey. Failure to use transient absorbers could result in
shortened relay life.
Littlefuse # Voltage Rating
1.5KE220CA 185 1500W
5KP180CA 185 5000W
P6KE33CA 28 600W
Operate time is 10 milli-seconds and release time is 5
milliseconds. Relays can operate with a battery voltage
of 9 volts (measured using register 9. Minimum value is
1232).
Maximum operations / hour is 1800. Maximum cycles
under resistive load is greater than 10,000 operations at
30 volts DC. Relay life increases when current through
contacts is reduced.
Opto Buffered Inputs
Eight opto buffered inputs are available at P3. Input
range is 0 - 16volts. The ground for each opto input is
common to board ground. This kind of opto input
affords good protection from transient voltages.
A minimum of 5 volts is required at an input to turn on
the opto isolator and designate that line as “ON”. Input
resistance is 2.74K ohm. Signal source must be able to
supply at least 5 milli-amps at 12 volts to turn on an
input.
RELAY OPERATION
Electrical Connection
Relays contacts are connected to P1 and P2. Relays are
wired into 3 groups. Each relay contact and common are
designated by letters A-M. Letters “I” and “J” are not
used.
2 groups have 1 common power and 2 switched relays. 1
group has 1 common and 4 switched relays.
First group schematic is shown below.
Terminal designated as C is common line for relays 7
and 8.
Second group schematic at P1 is wired similar to the first
group.
Terminal designated as F is common line for relays 5 and
6.