SiteManager xx29/xx39 - Working with I/O ports Page 8 of 12
Version 2, April 2013
3. Digital Output Ports
3.1. Electrical information
The output ports of the SiteManager are of the “open drain” kind, which
means that (just like a switch) no voltage is output by the port itself, but must
be controlled from a circuitry supplied by an external source (max 24V) or
from the Vout (5V) pin.
Do NOT apply voltage (e.g. 24V) directly to the SiteManager Output
ports, as this could permanently damage the ports.
In the “OFF” (inactive) state, the impedance is min 24 Mohm; in the “ON”
(active) state, the impedance is max 0.5 ohm.
Maximum sink current is 0.2A, which means the Output ports are protected
by 0.2A fuses mounted in extension to the FET transistors of the Output
ports. But is still very important to dimension the external circuitry to not
overload the ports. At 24V you should therefore apply pull-up resistors at
minimum 24V/0.2A = 120 ohm (24V*0.2A = 4.8W), but it is recommended to
not exceed 3W, meaning a pull-up resistor of 220 ohm is recommended.
These pull-up resistors must
A 12V or 24V relay can be applied to an output port directly if the relay is
supplied with the corresponding working voltage (12V or 24V respectively)
and with a "trigger current" at max 0,2A. (A larger relay would require more
current, and subsequently would require an additional "assisting" relay for
the SiteManager output ports to trigger it)
be applied externally, unless you are using a
relay which has a high enough impedance.
3.2. Output ports default functionality
Output port 1 is dedicated to go active when connecting with Go To Appli-
ance from GateManager, LinkManager Mobile, or LinkManager's domain
view. and can be used to turn on an external warning light that tells local
service people to be extra careful, because the machine is currently being
serviced from remote.
Output port 2 can be set ON or OFF via the toggle button in the SiteManager
web GUI under System > I/O. But it can also be configured to go active
when a working GateManager connection is available. This can be used to
inform an operator that the Internet connection may be down. (ref. to section
3.5 Changing Output 2 default functionality)
