HI. Thanks for that.
I have been investigating a bit further. I am basically trying to get an old weaving loom working. It has a controller for the "shafts" which latch with the solenoids. It has a Z80a on board controller. I examined the drive ciruitry and have drawn (probably badly but I think correctly) the schematic for the bit that controls the solenoids (and therefore the latches).
Each output to the latches comes in two parts. The first is a global pulse to all the solenoids so they are all in an unlatched state. Then immediately after that there is a pulse to all the solenoids that need latching, presumably by the transistors. (bc182). There are two relays that must reverse the polarity for both pulses.
Can anyone suggest a good way to proceed. Is there a more modern solution? I still have my uln8203s for driving the solneoids in one direction. I think it would be too difficult to try to use the existing drive card.
I think the point is that when a shaft is latched and the loom treddled, that shaft has to be unlatched for the next treddle otherwise one would be unweaving the thread. That is probably why a global unlatch is sent each time.




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