this msg is for those who are looking for a relay board for their -18x project.
here is some of what has been learned using one from .phanderson.com :
the $50 . 'serial relay & optoisolator module' he offers lets you control
up to 4 relays at once using the serial link. or the opt'l opto' link
as a minimum it uses 2 wires from
the -18x. one for a 'serout' command to the relay board, the other for COM.
using 3 wires lets you get feedback from the module's uC. now you can
learn the state of the relays or the optoisolators. the module auto'ly
spits out every second the status info. all you need is a 'serin' cmd to catch it.
the relays all are 3-terminal : NO , NC , and COM
and handle both DC and AC.
the 4 opto inputs allow you to use 4 of the 8 -18x output pins if you want to
wire it up that way. this will require 5 wires : 4 for the opto's and 1 COM
one caution learned is that by going the serial route the on/off signals
get latched. ex. if you send the cmd to 'on' a relay and then the -18x loses
power the relay remains in that 'on' condition forever . or until its wal-wart power is lost.
as that is where the relay coil power comes from.
whereas if all the relay on/off signals go via the opto's then there is no latching.
a relay with an 'on' signal turns off soon as the opto 'on' signal is lost.
here is some of what has been learned using one from .phanderson.com :
the $50 . 'serial relay & optoisolator module' he offers lets you control
up to 4 relays at once using the serial link. or the opt'l opto' link
as a minimum it uses 2 wires from
the -18x. one for a 'serout' command to the relay board, the other for COM.
using 3 wires lets you get feedback from the module's uC. now you can
learn the state of the relays or the optoisolators. the module auto'ly
spits out every second the status info. all you need is a 'serin' cmd to catch it.
the relays all are 3-terminal : NO , NC , and COM
and handle both DC and AC.
the 4 opto inputs allow you to use 4 of the 8 -18x output pins if you want to
wire it up that way. this will require 5 wires : 4 for the opto's and 1 COM
one caution learned is that by going the serial route the on/off signals
get latched. ex. if you send the cmd to 'on' a relay and then the -18x loses
power the relay remains in that 'on' condition forever . or until its wal-wart power is lost.
as that is where the relay coil power comes from.
whereas if all the relay on/off signals go via the opto's then there is no latching.
a relay with an 'on' signal turns off soon as the opto 'on' signal is lost.
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