# Resistor Calculation Mesa 7i76e <-> Leadshine ES-DH1208 ?

#### shanham67

Joined Oct 12, 2021
6
All,

I am integrating a Mesa 7i76e controller with a Leadshine ES-DH1208 drive. Can someone help me determine the value of the external resistor shown between the +5V and ALM+ pin in the diagram below. Please note I am using a 24VDC power supply for inputs and outputs to the 7i76e.

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#### sghioto

Joined Dec 31, 2017
5,369
I would try using a 22K resistor.
If that doesn't work try a 10K.

#### Ylli

Joined Nov 13, 2015
1,083
Per the spec, the input impedance is 20K and it needs 14.4 volts to assure a high. I = E/R = 14.4/20 K = 0.72 mA.
The pullup resistor needs to drop 9.6 volts with a current flow of 0.72 mA. R = E/I = 9.6/0.74 mA = 13.333333K

So anything less than 13.3333K should guarantee an input of at least 14.4 volts. I would suggest 10 K

#### shanham67

Joined Oct 12, 2021
6
All,

I am integrating a Mesa 7i76e controller with a Leadshine ES-DH1208 drive. Can someone help me determine the value of the external resistor shown between the +5V and ALM+ pin in the diagram below. Please note I am using a 24VDC power supply for inputs and outputs to the 7i76e.

View attachment 300176
FYI All - 2.2K resistor gives me 20.5V for high and 1.7V for low

#### sghioto

Joined Dec 31, 2017
5,369
Did you try a 10K and what were the results?