ICS ELECTRONICS 4809A, Instruction Manual

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2.10 Modbus Device Connections
2.10.1 RS-232 Connections to a Modbus Device
The minimum RS-232 connection uses just three lines to connect the unit
to a Modbus slave device. The lines are transmit data (TxD), receive data
(RxD), and Ground. The following examples show how the 4899A, 4809A
and 4819A are wired to some typical RS-232 Temperature Controllers.
Refer to Table 5-2 for troubleshooting Modbus Device communication
problems.
Figure 2-10 shows the 4899A or 4809A RS-232 connection to a Watlow
F4 Temperature Controller. Both interfaces transmit on pin 2 and receive
on pin 3.
1
2
3
4
5
6
7
.
.
25
4899A
or
4809A
WATLOW F4
4899A/4809A
TXD
RXD
1
.
.
12
13
14
15
16
Figure 2-10 4899A/4809A RS-232 Connections to a Watlow F4
Figure 2-11 shows the 4819A's RS-232 connection to a Watlow F4 Tem-
perature Controller. The 4819A's transmit signal is on pin 3 and its receive
input signal is on pin 2 with the DCE/DTE jumpers W4 set in the DCE
position. Switch jumper W4 to the DTE direction to swap the signal pin
assignments.
1
2
3
5
:
9
4819A
4819A
RXD
TXD
1
.
.
12
13
14
15
16
GPIB
Serial
76
WATLOW F4
Figure 2-11 4819A RS-232 Connections to a Watlow F4