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« on: February 05, 2020, 01:44:49 PM »
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Note that the internal 24V power supply is available at pin 17. Following the diagram you should direct connect pin 17 to pin 35.
With pin 35 now at 24V current can pass through the approx. 2kOhm resistor the 75 Ohm resistor, through the photodiode, through
the second 75 Ohm resistor to pin 37 and thence to the 24V COM at pin 14 via the transistor switch of your BoB or input circuit.
There is a second current path through the 2kOhm parallel resistor as well.
You can test the photodiode by having pins 17 and 35 connected as above. Then with your multimeter in ammeter mode probe
between pin 35 and pin 14. If the photodiode is intact I would expect a current of (24-2)/(2000 +75 +75)=10mA plus another
24/2000=12mA being the current through the 2kOhm parallel resistor, for a total of 22mA. If the photodiode is open circuit
you'll see only 12mA.
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Per your sugesstion above, I have used my cheap digital MM to check what I think is mA, on the meter it is marked 200m. this appears to be in the A_--- range. I am not positive about this, but this is the only setting which appears to me mA.
The range specs are here-
Specifications:
DC Current: 200μA/2mA/20mA ±(1.0%+2), 200mA ±(1.5%+2); 10A ±(3%+2)
wioth 17 and 35 connected (24vdc+ is present from drive pin 17) I have tried reading across pins 35 and 14, and I get nothing until I hit the 200mA range and then the drive clicks, displays the drive model ASDAB2 on the drive screen. The meter appears to read 124 at this time, and as I continue reading it, the number starts dropping at a fairly quick rate. I suspect if I continued holding the meter leads in place it might take a minute or two for the numbers to hit zero. Just a guess though, I did not test this theory.
by the way, the warning sticker that you referred to was on the drive. It looked important, but wasd not sure in waht way, so I stuck it to the dide of the drive for later use.
This brings me to the question of the resistors. I am not clear on where the resistors are in the real world. are the 2kohm and 75 ohm resistors contained in the asdab2 drive? thats the way the delta schematic and warni ng stiucker look to me, but I am really starting to suspect the resistors NOT contained inside the drive, but rather I must provide and hook them up external to the drive.
I really wish I had not read the CX-X wiring diagrams as having the resistors, diodes and transistors as being contained inside the drive. This is what happens when you have little understanding of electronics. But hey.. gotta learn somehow.
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