red lion PAXI - 4.5 PAXI SERIAL COMMUNICATION WIRING; 5.0 REVIEWING THE FRONT BUTTONS AND DISPLAY

11
RS232 Communications
RS232 is intended to allow two devices to communicate over distances up to
50 feet. Data Terminal Equipment (DTE) transmits data on the Transmitted Data
(TXD) line and receives data on the Received Data (RXD) line. Data Computer
Equipment (DCE) receives data on the TXD line and transmits data on the RXD
line. The PAX emulates a DTE. If the other device connected to the meter also
emulates a DTE, the TXD and RXD lines must be interchanged for
communications to take place. This is known as a null modem connection. Most
printers emulate a DCE device while most computers emulate a DTE device.
Some devices cannot accept more than two or three characters in succession
without a pause in between. In these cases, the meter employs a busy function.
As the meter begins to transmit data, the RXD line (RS232) is monitored to
determine if the receiving device is “busy”. The receiving device asserts that it
is busy by setting the RXD line to a space condition (logic 0). The meter then
suspends transmission until the RXD line is released by the receiving device.
RS485 Communications
The RS485 communication standard allows the connection of up to 32
devices on a single pair of wires, distances up to 4,000 ft. and data rates as high
as 10M baud (the PAX is limited to 19.2k baud). The same pair of wires is used
to both transmit and receive data. RS485 is therefore always half-duplex, that
is, data cannot be received and transmitted simultaneously.
12
12
B(-)
33K
33K
33K
33K
+5V
+5V
Transmit
Transmit
Enable
Enable
PAX METER
PAX METER
RECEIVING DEVICE
RECEIVING DEVICE
A
(+)
(+)
COMM.
COMM. *
NC
NC
*
OPTIONAL
OPTIONAL
13
13
14
14
15
15
Terminal Block Connection Figure
12
TXD
RXD
COMM.
PAX METER (DTE)
RECEIVING DEVICE
2
NC
RXD
TXD
3
32
75
5
DTE
3
2
DB9
13
14
15
DTEDCE
DB25DB25
Terminal Block Connection Figure
19
-
18
+
17
-
16
+
ANALOG
OUTPUT
OUTPUT
0-20mA
0-10V
ANALOG
ANALOG OPTION CARD FIELD TERMINALS
5.0 REVIEWING THE FRONT BUTTONS AND DISPLAY
Counter
Readout
Legends*
Setpoint Alarm
Annunciators
RSTDSP
PAR
F 1 F2
A
C
B
SP1 SP3
SP2
SP4
8.8.8.8.8.8
* Counters B, and C are locked out in Factory Settings (PAXC and PAXI only).
** Factory setting for the F1, and F2 keys is NO mode.
*** Factory setting for the RST key is
 (Reset Display).
Advances digit location in parameter valuesReset (Function key) ***RST
Decrement selected parameter value or selectionsFunction key 2; hold for 3 seconds for Second Function 2 **F2

Increment selected parameter value or selectionsFunction key 1; hold for 3 seconds for Second Function 1 **F1
Store selected parameter and index to next parameterAccess Programming ModePAR
Quit programming and return to Display ModeIndex display through the selected displays.DSP
PROGRAMMING MODE OPERATIONDISPLAY MODE OPERATIONKEY
4.5 PAXI SERIAL COMMUNICATION WIRING
4.6 PAXI ANALOG OUTPUT WIRING
4.7 PAXI PRESCALER OUTPUT WIRING
1
5
9
6
PIN 3 RXD
PIN 5 COMMON
FEMALE
PIN 2 TXD
Extended Comms Connection Figure
3542
PAX CONNECTOR
Not used Not used Not used
B- A+
COMM
Extended Comms Connection Figure