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CHAPTER 3: Installation
3.1.4 CTS D
ELAY
(W9 J
UMPER
)
When the transmitter of a device is first turned on, an unstable carrier signal is
transmitted for several milliseconds. If data was sent during this period, it would be
received as distorted information. Setting a CTS delay on the RS-232↔485/422
Converter allows the communications link to settle down before data can be sent.
RS-232↔485/422 Converter as DCE (XW1A 8-Position Shunt)
When the RS-232↔485/422 Converter is configured as a DCE device (DIP shunt
in position XW1A), jumper W9 controls the amount of delay from the time RTS
(jumper W5 in the A-B position) is received true until CTS is asserted true. If W5 is
in the B-C position, CTS will be inhibited if an RS-485 carrier is present when RTS
is raised. To select a CTS delay period, set jumper W9 to the 0-, 10-, or 30-msec
position. Regardless of the delay setting selected, when RTS goes false, CTS will
immediately go false. If jumper W9 is in the “ON” position, CTS will follow RTS.
RS-232↔485/422 Converter as DTE (XW1B 8-Position Shunt)
When the RS-232↔485/422 Converter is configured as a DTE device (DIP shunt in
position XW1B), CTS is not supported.
3.1.5 RS-485 D
RIVER
E
NABLE
(W15)
The RS-232↔485/422 Converter’s RS-485 driver can be set to be enabled one of
three ways: by RS-232 control signals, by data, or constantly on via W9 set in the
ON position).
Driver Enabled by RS-232 Control Leads
If your equipment raises CD or RTS when it is ready to send data, you can set the
RS-485 driver to be enabled by one of these leads. If your equipment does not have
the capability to raise CD or RTS, you will need to set the RS-485 driver to be
enabled by data or constantly enabled.
In order for an RS-232 control lead to enable the RS-485 driver, W15 must be in
position A-B and W9 must be set for 0, 10, or 30 ms.
• When the RS-232 port is selected as DTE (DIP shunt in the XW1B position),
the RS-485 driver will be enabled when CD (pin 8 of the RS-232 connector)
goes true.
• When the RS-232 port is selected as DCE (DIP shunt in the XW1A position),
RTS enables the driver.
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