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khun
March 7th, 2007, 08:57 AM
Hi!

I have found a lot of tips on different boards for switching relays from Girder. From my point of view, Phidgets 8/8/8 seems like the best choice.

But beeing more into software than hardware, I have some trouble seeing exactly what I need! I want to control 5 different radiator actuators, each one needing 24V/350mA (or 2W in standby) to open and keep open the radiator valve.

The specification of the Phidgets board states quite clearly that the output can not be used to _power_ anything, only to _switch_ something. So what do I need between the output wires from the board and my actuators to actually supply them with 24V??

Thanks for any help!

khun

mhwlng
March 7th, 2007, 09:13 AM
have you see this :

http://www.hobby-boards.com/catalog/product_info.php?cPath=24&products_id=1504


works fine from girder (you can add multiple boards), can switch 3 amp and 250 volt AC.


Marcel

khun
March 7th, 2007, 06:37 PM
but I'm still a little lost in technical terms. I have tried to read their information on 1-wire networks, which is very interesting. It would be very nice with a confirmation of my interpretation:

A. To control 4 actuators, I need:
a: the 4 channel relay
b: 1-wire USB adaptor
c: Adaptor cable RJ45 to RJ11
d: A power supply big enough to provide power to 4 of my actuators at the same time (4x350mA, 24V) + 250mA for the relay board itself. This is connected to the 4 channel relay board.
e: one RJ45 cable for each actuator, where I connect 1,3,5 or 8 to GND on the actuator, and 7 to power.

B: For 4 more, I would need in addition to A:
f: an RJ45 cable (to connect one 4 channel relay to the next)
g: an additional power supply? Or if the one on the first board is big enough, could I draw power for the actuators on the second board (and for the second board) from that as well?
h: one RJ45 cable for each additional actuator.

Having this (and the appropriate drivers), I can easily send commands from Girder telling each actuator to be on or off? Do you think a cable length of max. 10m from the relay board to the actuator would give me problems with the voltage?

Thanks again for any help! Really appreciated!

mhwlng
March 8th, 2007, 02:21 AM
A. To control 4 actuators, I need:
a: the 4 channel relay

yes

b: 1-wire USB adaptor

or get a 6 channel master hub instead (which is serial, not usb),

http://www.hobby-boards.com/catalog/product_info.php?cPath=23&products_id=1511

which has 6 rj45 connectors

(this is optional, a 1-wire USB adapter should also work fine)

c: Adaptor cable RJ45 to RJ11

yes, see above

d: A power supply big enough to provide power to 4 of my actuators at the same time (4x350mA, 24V) + 250mA for the relay board itself. This is connected to the 4 channel relay board.

note that the relays are 5V relays, so the voltage regulator on the relay board will get very hot if you power it with 24 V.

a second lower voltage power supply just for the relay board (e.g. 12V or 9V) is better

e: one RJ45 cable for each actuator, where I connect 1,3,5 or 8 to GND on the actuator, and 7 to power.

the relay board has 3 screw terminals per relay, so I'm not sure why you would need an rj45 cable, do your actuators have an rj45 connector ?


B: For 4 more, I would need in addition to A:
f: an RJ45 cable (to connect one 4 channel relay to the next)

yes

g: an additional power supply? Or if the one on the first board is big enough, could I draw power for the actuators on the second board (and for the second board) from that as well?

see above

h: one RJ45 cable for each additional actuator.

see above

Having this (and the appropriate drivers), I can easily send commands from Girder telling each actuator to be on or off?

yes

Do you think a cable length of max. 10m from the relay board to the actuator would give me problems with the voltage?

no problem.


Marcel

khun
March 8th, 2007, 05:54 AM
to ordering now :-)

I'm still unsure about the power, though, sorry to be so slow :-)

Do I need 1 5V power supply for the board itself and the relays and then another to power the actuators? Where would I then connect the supply for the actuators, when there is only 1 power jack plug (which I'm now guessing is for the board's power)?

As far as I can see from the board layout, there are only 2 connections per relay (you say there are 3)? See http://www.hobby-boards.com/catalog/product_info.php?products_id=1506 and enlarge the picture. It seems that 5/6, 7/8, 9/10 and 11/12 are connected to relays 1-4. Outputs 3 and 4 are connected, 2 is DQ and 1 is GND.

I can't quite make sense out of this, help appreciated!

mhwlng
March 8th, 2007, 06:03 AM
you are correct, there are only 2 connections per relay

the schematic of the board is on the webpage...

there is no power jack plug (just screw terminals and rj45 sockets) !

I assume that you connect 24V to one connection on each relay, the other connection of each relay goes to an actuator

you connect 9-12V (not 5V) to the board.

and the ground of both power supplies, the board and all the actuators needs to be connected together...

Marcel

khun
March 8th, 2007, 06:34 AM
Ok, you've got me convinced :-)

I'll order now and look forward to connecting all of this! If I get it up and working before april 1st, I will get refunded 20% of the cost from Enova (in practice from the norwegian government). This is their contribution to lower energy consumption in the world

Thanks again!