Watlow Series 96 User Manual
Page 14
3 . 8
■
W i r i n g
Wa t l o w S e r i e s 9 6
Figure 3.8a – EIA-232 to EIA-485 Conversion
B&B Converter (B&B Electronics Manufacturing Company, [815] 433-5100).
CMC Converter (CMC Connecticut Micro-Computer, Inc., 800-426-2872).
NOTE:
The CMC converter requires an external power supply when used with a laptop computer.
Figure 3.8b – Termination for EIA-232 to EIA-485 Converter
NOTE: For more information about communicating with Watlow controllers, go to
www.watlow.com and download the Data Communications Reference: Electronic User’s
Manual. It is located under Literature, User’s Manuals, English and search on data
communications reference.
+5V
B
A
GND
T+/R+
T-/R-
Com
1K
Ω
120
Ω
1K
Ω
Converter box
termination
with pull-up
and pull-down
resistors.
9V
Î
(dc) (see note)
120V~ (ac)
COM.
T-/R-
T+/R+
0219-0217-0000
7-ft. comms cable
EIA-232
ADA485L
EIA-485
A
B
A
B
G
9V
Î
G
DI/O
DI/O
21
19
20
T-/R-
TD (A)
TD (B)
RD (A)
RD (B)
T+/R+
120V
~
(ac)
EIA-232
EIA-485
EIA-485
Power S
up
ply
AD-1210
+
–
GND
GND
COM.
19
20
21
485OIC
+12VÎ(dc)
+12VÎ(dc)
(232 power)
ç
WARNING:
To avoid damage to
property and equipment,
and/or injury of loss of
life, use National Electric
Code (NEC) standard
wiring practices to install
and operate the Series
96. Failure to do so could
result in injury or death.
If the system does not work properly, it
may need termination resistors at each
end of the network. A typical installation
would require a 120-ohm resistor across
the transmit/receive terminals (19 and
21) of the last controller in the network
and the converter box or serial card. Pull-
up and pull-down resistors may be
needed to maintain the correct voltage
during the idle state.