One more HURCO BMC 20P Retrofit

Example, roughly:
24V/20KOhm = 24/20000=0.0012A
That is 1.2mA, so no matter how much amps the power supply can put out, it will be the maximum an input will use.

Hey guys!
Thanks for putting up with me.

As my level of electronics is obviously lower than the one needed to get everything wired up fast, I decided to start a wiring diagram so I could evaluate all connections beforehand. I will share it with you when it comes to a “readable” state.

Now, I have a different question. As you have noticed correctly, the 7i77 has a 20kΩ input resistance, but when I have checked the resistance using a digital multimeter, I’m getting a different result (with no power anywhere).

Attached a photo, why am I getting 10.9kΩ? Do I have a different version of a 7i77?
 

From the 7i77 manual, the inputs have a nominal 20 kΩ input impedance

Impedance and resistance are not the same thing, although pretty close.
So 11Kohm would be roughy 2.5mA or 0.0025A.
Short explanation, impedance is resistance that changes depending on voltage or current, so it is used for inductive loads, like speakers.

id6 not be worried about it the difference between 11k and 20k in terms of current is inconsequential amd maybe be a result of your meter not being accurate. many meters are not accurate. if you are measuring resistance check from the 7i77 ground terminal on the tb connectors to your input.

christos wrote:

Attached a photo, why am I getting 10.9kΩ? Do I have a different version of a 7i77?

You cannot measure resistance of semiconductor circuitry like that. The DMM applies a small, known current between its test leads, measures the resulting voltage, and calculates the resistance using Ohm's law (U=R*I). This only works with purely resistive elements, not with semiconductor parts. The result will be nonsense - for example, you are likely to get a different value by simply switching the test leads around.

Hello guys

After a couple months of inactivity due to personal issues we are back with a bigger appetite to complete this project. It has been quite a steep learning curve for me (linux, linuxcnc, electronics) but we are slowly getting there.

After all encoder feedback is connected, and while in the process of connecting the Yaskawa servopacks to the 7i77, I have a query regarding the pncconf wizard.In the pncconf wizard, I think I was missing the correct firmware so the 7i92 can properly display the connections between itself and the two mesa cards connected to it, the 7i77 and the 7i74.

I have found the firmware (7i92_7i77_7i74D.bit) downloaded and successfully (I think) loaded it. But when I’m opening to create a new pncconf wizard I still do not get the option of the firmware I have installed. What I’m doing wrong here? Is there another way to do it rather the command:

mesaflash --device 7I92 --addr 10.10.10.10 --write 7i92_7i77_7i74D.bit