Using The Rs-485 Port Connector (J8) - SPX Hankison GCU Series Instruction Manual

7. To reinstitute SCHEDULED MODE, push 'Schedule On/Off
and Enter' button.
IMPORTANT: Dryer must be energized 24 hours before
refrigeration compressor is started
Operating check points
E.
1. Check that green Power-on light is illuminated
2. Check that green Compressor-on light is illuminated if
dryer is on in the manual mode or it is a scheduled on
time
IMPORTANT: Refrigeration compressor must be restarted
after power interruption.
3. Check interface panel
NOTE: Interface panel will scroll through three screens
(Current Time/Operating Status, Hours to Service and Total
Operating Hours).
a. Verify that current time is correct
b. Check HRS TO SERVICE: this indicates time remaining
until service is required; allow time for required
maintenance items to be ordered
c. Check operating status:
MANUAL MODE - Dryer is either running continuously
(not being controlled by the scheduled on/off times)
or the refrigeration compressor has been shut off
using the 'On/Off' button.
SCHEDULE MODE - Refrigeration compressor
is being turned on and off by the monitor per-
programmed schedule (see B.3. to set schedule).
d. Check Temperature indicator - indicator should read
in the green area.
e. Check Alarm/Service light If illuminated, check
Interface panel.
1) If SERVICE DRYER appears, scheduled maintenance
time has elapsed (HRS TO SERVICE is 0). Perform
needed service and reset service interval (see B.3.).
2) If ALARM appears, a dryer fault is indicated; see
Troubleshooting Guide for possible remedies.
After fault correction push Reset button to turn
Fault alarm off.
Type of FAULTS:
LOW PRESSURE - the refrigeration compressor
control circuit has opened because of low suction
pressure.
HIGH PRESSURE - the refrigeration compressor
control circuit has opened because of high head
pressure. The high pressure switch must be reset
manually once the fault is corrected. Red reset
button is located on pressure switch inside unit.
HIGH TEMPERATURE - compressed air temperature
is above the set point.
COMPRESSOR - Normally open (NO) auxiliary
contact on the compressor contactor is open
when the dryer is on.
HEATER - Normally closed (NC) auxiliary contact
on the compressor contactor is open when the
dryer is off.
6
TEMP SENSOR - Occurs if the temperature
sensor circuit is open or shorted. If open, none
of the LED's in the temperature display will
be illuminated. If shorted, all the LEDs in the
temperature display will be illuminated.
DRAIN - electric drain contains a high water level
alarm that activates if drain fails to discharge.
f. Check drain operation - push Drain (push-to-
test) button to energize electric drain. A flow of
condensate and/or air should be present at the drain
outlet.

2.3 Using the RS-485 Port Connector (J8)

This connector provides RS-485 compatible signals from
the internal master microprocessor. Using jumpers on
the headers supplied near the connector (J12), 120 ohm
termination resistors can be connected and the system can
be connected for either two-wire or four-wire operation
(half or full duplex). To connect the termination resistors,
install jumpers on J12 in the direction shown by the white
bars printed above the connector.
If the jumpers are removed no termination of the RS-485
bus is in effect. Usually, these jumpers must be in position
for proper operation of the bus.
J10 contains the two-wire/four-wire jumper. If the jumper is
set in W2 place, the circuit is set up for two-wire operation. If
the jumper is set in W4 place, the circuit is set up for four-wire
operation. Selection of jumper settings must be determined
by the customer's system. The jumpers are supplied as
standard and are installed as shown at the factory. Be sure
to set the jumpers properly for your system.
RS-485 Pinout
Following is the pinout for J8, the RS-485 communications
connector.
1 A
2 B
3 Z
4 Y
When connected in two-wire mode, the bus wires may be
connected to pins 1 & 2. Also note that when in two-wire mode,
one termination resistor jumper should be removed to prevent
the termination from being too low in value. It may be stored
on the top set of pins on J12. Those pins are not connected.
Please make sure that your connections are properly made. This
connector is a 4-pin terminal block. Mating connectors are not
supplied. The electrical signals supplied by this connector are
TIA/EIA-485A compliant. A good cable should be used to transmit
signals such as Belden 3109A or equivalent.
Communication Parameters:
RS-485 Parameters
Baud Rate 19200
Data Bits 8
Parity None
Stop Bits 1
Flow Control None
Factory Default = 1
Modbus Drop I/O
(user adjustable 1 - 247 )