Re: AXBB charge pump fault
Does the other outputs work as expected ?
Assuming the output transtor is open drain and grounds the relay coil terminal to switch the relay on
With the power off you can use a multimeter to check the resistance between the negative supply terminal and each isolated output
in the manual
http://www.cncdrive.com/downloads/AXBB_E_manual.pdf
see diagram 9.1.2 .Connecting a solid state relay (SSR)
test between 24V0 and Ox
You should find they are all open circuit unless the transistor controlling the relay is short circuited
John
Re: AXBB charge pump fault
Cheers John, I'll check the resistance tomorrow but one more thing I remembered. I also tried output 2 of the isolated outputs and that one does read the voltage change if I set that as the charge pump output however that one doesn't activate the relay? The manual states that the isolated outputs can drive upto 500mA so I'm assuming it's not enough power to drive the relay and the output 1 is different. [emoji848]
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Re: AXBB charge pump fault
what relay are you using ?
any idea what the coil resistance is ?
This one from RS Components has a coil resistance of 650 ohms
https://docs-emea.rs-online.com/webd...6b815856e9.pdf
If the RS StockNo:450-0425 relay was used with the AXBB and its 24V DC supply only 37 mA would flow via the AXBB output
John
Re: AXBB charge pump fault
It's like the one below
https://rover.ebay.com/rover/0/0/0?m...2F283248324744
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1 Attachment(s)
Re: AXBB charge pump fault
going by this data sheet
Attachment 26191
your relay also has a resistance of 650 ohms
page 4
Non-latching – DC
rated voltage = 24V
rated current = 36.90 mA
coil resistance = 650 ohms
John
Re: AXBB charge pump fault
Forgive my ignorance but does that mean the other isolated outputs are all capable of driving the relay? I did check that and thought so but its been a while since I DoD electronics!
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Re: AXBB charge pump fault
Quote:
Originally Posted by
john swift
With the power off you can use a multimeter to check the resistance between the negative supply terminal and each isolated output
in the manual
http://www.cncdrive.com/downloads/AXBB_E_manual.pdf
see diagram 9.1.2 .Connecting a solid state relay (SSR)
test between 24V0 and Ox
You should find they are all open circuit unless the transistor controlling the relay is short circuited
John
It looks like I'm getting approximately 100 ohms on output 1 to ground, all other outputs are open.
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Re: AXBB charge pump fault
The reference to " other isolated outputs are all capable of driving the relay "
differentiates the outputs from the 5V logic level outputs that you connect to other logic gates or the stepper driver step & direction inputs
from the open drain outputs designed to switch inductive loads like the relays
As an example
Going back to equipment I used and maintained in the eighties
all the logic was built from 7400 series TTL logic
Typical gate inputs passed 1.6 mA when an input a input was grounded
and the outputs could sink 16 mA
so you could only connect 10 inputs to the output of an IC
unless you used a buffer that could pass more current
To connect to other devices like tally lights for the control panel switches
A lamp “driver” / BCD decoder like the 7445 switched 28v bulbs ( run off a 24V supply ) by grounding the other end of the bulbs filament
The 74141 being another version with high voltage outputs for driving Nixie tubes
(which is basically a neon with an anode connected to 180V DC via a resistor and 10 cathodes shaped in the form of the digits 0 to 9 that glows when grounded )
These days you would use a 7447 BCD to 7 segment decoder driver connected to a 7 segment LED display or LCD
John
Re: AXBB charge pump fault
It looks like the FET for output 1 has short circuited
I would check you don't have a wiring problem that could connect the 24V DC to the AXBB output
Did you check the relays coil resistance is 650 ohms as expected
less than 48 ohms would pass more than the 500mA limit for the output
John