10-08-2020 04:37 AM
This may be a silly question but I have a PXI-2503 with its 1A per channel maximum current. However, i'd like to switch a Thorlabs light source (12V@3A) on and off with it and cant buy another unit with higher currenys per channel. Is it possible to use 3 of the channels in parallel with say three COM outputs connected in parallel ? I'm wondering if i can configure the quad 6 x1 topology bit tie three + and three - chanels to the 12V and ground lines and the three respective COM+ and COM-1 lines to the light source requiring the 12V@3A.
Any ideas or comments ? I dont want to dry the relay/multiplexer.
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10-13-2020 12:02 PM
It is possible, you could gang up relays to increase the current capacity.
IMHO, it is best to parallel 4-5 channels so that you are giving some headroom to avoid damaging channels by overload.
Caution - do not switch the relay with a load, because all the 4-5 relays do not switch exactly at the same time, some of the relays could be overloaded for a fractional duration (damaging or shortening the life).
a better way is, make sure the power supply 12V@3A is powered down, switch relay states, power up the supply. This way, the relay contacts have already denounced and sure that all the relays are switched (avoids overloading one of the relays). Same way, before opening the relays, be sure to power down the supply or the load.
10-15-2020 06:36 PM
I thought that might be the case. Seems a waste of the card to dedicate this many channels so I've just bought a 5$ relay to switch with my other PXI daq card (digital I/O).