Manual
IQ-INT II IQ Interface
Page 10
Reference Manual
Fig. 3.11 Communication Settings for the IQ-INT II
12345678
SW1
SW1
12345678
ON
OFF
1
2
5
6
7
8
ODD
EVEN
38400
19200
9600
4800
1200
600
2400
PARITY
STOP
BITS
DATA
BITS
PARITY
BAUD
RATE
Factory-set switch positions are highlighted.
300
C
O
M
P
U
T
E
R
RS232 / RS422
U
S
E
S
ID
E
A
C
C
E
S
S
H
O
L
E
T
O
S
E
T
B
A
U
D
R
A
T
E
A
N
D
O
T
H
E
R
C
O
M
S
E
T
T
IN
G
S
.
IN OUT
1
IN OUT
2
IN OUT
3
IN OUT
4
IN OUT
5
IN OUT
6
IN OUT
7
IN OUT
8
1
2
3
G
N
D
1
2
IN
P
U
T
W
I
R
I
N
G
O
U
T
P
U
T
W
I
R
I
N
G
3.2.2 Communication Settings
Before communication can take place between the unit
and a host computer, the communication standard must
be selected and the communication parameters must
be set with switches accessed through an opening in
the side of the chassis (see Figure 3.11).
IMPORTANT: Be sure to disconnect the AC power
from the unit before changing the communication
standard or parameters.
Setting the communication parameters for RS232 and
RS422 serial communication is accomplished using the
eight segment DIP switch shown in Figure 3.11. The
first five switches set the parity, number of stop bits and
data bits. These five switches should ONLY be set in
the positions shown in Figure 3.11. The last three
switches set the baud rate. Use the fastest baud rate
possible.
IMPORTANT: The communication standard and
parameters of the IQ-INT II and the host computer
must be the same. Any mismatch will prevent
communication from taking place.
The communication parameters of the host computer
are set using the IQ software. Please refer to your IQ
software manual for details.
Here are some important guidelines when configuring
serial communication:
• Use these communication parameters for the
interface and the host computer: The
IQ-INT II
should be set at one baud rate below
the host
computer (refer to your IQ software manual). Stop
bits, data bits and parity checking should be set to
their default values.
• The
IQ-INT II
can be set as high as 38.4 K baud.
Use the highest baud rate possible, but be aware
that the communication circuitry (UART) in some
PC’s cannot function over 9600 baud. We strongly
recommend using a host computer serial interface
with a 16550-compatible UART.
• Do not use twisted-pair wire for RS232 cables
because the unbalanced wiring of RS232 is
susceptible to crosstalk. Instead use an untwisted
cable or ribbon cable. Data grade twisted-pair wire
should be used for RS422.
• If the host computer fails to communicate or reports
communication errors with the
IQ-INT II
and the
communication standard and parameters are
identical, try reducing the baud rate for the interface
and the computer. This may be especially useful
when configuring for communication via modem.
IMPORTANT: The
IQ-INT II
should be set at one baud
rate slower than the modem is set for accurate
communicaton. (Example: 14,400 modem, set
the
IQ INT II
at 9600.)
• If communication problems persist, check the serial
cable for improper wiring or possible shorted or
broken wires.
• For further assistance, refer to the Troubleshooting
section in your
IQ System
software manual, or
contact Crown’s Technical Support Group.