DFE WebHandler 3 Instruction Manual page 31

Figure 24 - RS232 / RS485 JUMPERS AND ADJUSTMENTS
(2) RS485 Since the TensionManager has RS232 as a standard interface, if RS485 communication
is desired, your WebHandler will need the RS485 option, or you can install the driver IC as
follows:
(a) Turn all power off and disconnect any cables
(b) On the Control board, remove U12 (MAX233) and store for later re-use.
(c) Install MAX491 (DFE P/N 104-0042) in socket U13.
You will then need to connect your WebHandler to your existing computer. Again, you will
need to wire appropriately for either 2-wire or 4-wire, as shown in the following figure:
Figure 25 - RS485 CABLE CONNECTIONS
For two-wire RS485 connections, use only pins 1, 4, and 5.
For four-wire RS485 connections, use pins 1, 2, 3, 4, and 5.
Regardless of the type of interface you are using, do not make connections to pins other than
those required for your interface.
Then, on the Control board in the WebHandler, Check jumpers JP2A and JP2B. If 4-wire is
used, do NOT install the jumpers. If 2-wire is to be used, install shorting jumpers on both pair of
pins.
Reference Control board in Figure 45 in Appendix A for location of IC's and jumpers.
25