IPL T CR48 • Communication and Control
Communication and Control
Ports Overview
Contact closure input ports
The contact closure inputs on the IPL T CR48 are able to detect
a closed circuit between any of the inputs and ground. The
contact closure input ports utilize a 1 kohm pull-up resistor in a
TTL (5VDC) circuit to sense external switch or contact closure.
By connecting one side of an external switch or relay to the
contact closure ground port and the other side to one of the four
contact closure input ports, logic 1 (closed) can be produced.
Logic 0 (open) can be produced by disconnecting either side of
the external switch or relay from the IPL T CR48.
Figure 4-1 — Equivalent circuit for control
closure input
Relay ports
The relay ports can be used for remote switching of low level
signals. The relays can be activated via software in three ways,
through
1. the Port Settings default Web page found under the
Conguration tab (see gure 4-5)
2. Telnet
3. an event script running on the IPL T CR48
The Port Settings Web page allows the user to turn any of the
eight relays “on” or “off.”
Telnet allows the user to send SIS commands (Refer to the
“Command/response table” later in this chapter) to turn the
relays “on” or “off” directly.
Event scripting allows an event script to turn the relays “on” or
“off” based on the state of the four inputs on the IPL T CR48, or
any other event script conditions.
States of the relay ports are volatile; if a given relay port is “on”
and the unit’s power is turned off, the state of the port is not
remembered. When the unit is powered on, the relay ports are
open and the corresponding LED will be “off.”
4-2
