• slider image 71
  • slider image 72
  • slider image 73
:::


Browsing this Thread:   1 Anonymous Users






0-5V轉換成4-20mA IC?
#1
新會員
新會員


查看用戶資訊
請問一下Microchip有0-5V轉換成4-20mA的IC嗎?
或有沒有其他的解決方案 謝謝

發表於: 2019/4/25 11:56
Twitter Facebook Google Plus Linkedin Del.icio.us Digg Reddit Mr. Wong 頂部


Re: 0-5V轉換成4-20mA IC?
#2
版主
版主


查看用戶資訊
沒有現成的元件可以使用。附件是我在 80 年代做的 4 ~ 20mA 的工業電流傳輸控制時的設計。

For a constant current loop design:
a.    If the Vref. = 5Vthe IL current is?
b.    If the Vref. = 2Vthe IL current is?
c.    If we change RL from 500 ohm to 100 ohm with Vref 2Vwhat will be the IL?
d.    What are the applications of the circuit?

Ans:  Gain for OP U1B = - V1(R1/R6) + V2[ (R1+R6)/ R1]* [R8/(R7+R8)] 
                    = -
V1 (500K/200K) + V2(700K/200K)(200K/700K)
                    = - 
V1 2.5 V2 1
                
,     if  V2 0  ,  Gain = -2.5

a
.    Vref 5VVR3 Vref / -2.5 = -2V , |IL|= | -2V/R3| = 20mA
b
.    Vref 2VVR3 Vref / -2.5 = -0.8V , |IL|= | -0.8V/R3| = 8mA
c
.    IL still equal 8mAThe IL doesn’t change.
d.    20mA current loop.

Attach file:



jpg  (0.00 KB)


發表於: 2019/4/25 12:59
Twitter Facebook Google Plus Linkedin Del.icio.us Digg Reddit Mr. Wong 頂部







You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.
You cannot use topic type.
You cannot use HTML syntax.
You cannot use signature.
You cannot create PDF files.
You cannot get print page.

[進階搜尋]