From: drowe67 <drowe67@01035d8c-6547-0410-b346-abe4f91aad63>
Date: Tue, 20 May 2008 23:49:11 +0000 (+0000)
Subject: minor edits, some more tests
X-Git-Url: http://git.whiteaudio.com/gitweb/?a=commitdiff_plain;h=232326222f0f30b5e14cba057df38acc2200e559;p=freetel-svn-tracking.git

minor edits, some more tests

git-svn-id: https://svn.code.sf.net/p/freetel/code@24 01035d8c-6547-0410-b346-abe4f91aad63
---

diff --git a/wispcar/documentation.txt b/wispcar/documentation.txt
index f7ebc0ab..63bd892f 100644
--- a/wispcar/documentation.txt
+++ b/wispcar/documentation.txt
@@ -133,6 +133,27 @@ when Vbat=40V).  Need higher Vce Q2 or change circuit to limit
 Vgs(max). Need to make sure sufficient Vgs to switch on Q1 at low
 Vbat.  Maybe two versions with different R1/R2?
 
+4/ Current Sensor resistor values.  When building the first soldered
+prototype I found that residual flux messed up the 10M R11 feedback
+resistor.  Scraping flux away and cleaning with solvent brought the
+resistance back up again.  This could be a problem with home
+construction, and possibly humid environments.  Perhaps we should
+scale resistors down to say 100k/10k voltage dividers, 1M R11?
+
+5/ When building the first soldered prototype I found that the
+position of the ground wires carrying high current caused the current
+sensor to stop working (stuck at 0V).  U2 GND and the GND of R7, R9,
+R10 where at different places along the GND track carrying 0.5A.  This
+caused a voltage drop of about 5mV between the two GNDs.  I moved the
+ground connection (made the GND in GND out points close to each other
+so 0.5A was only flowing thru a short section of track) and the
+current sensor started working again.  This suggests a carefully laid
+out PCB is a good idea.
+
+6/ The voltage on pins 2 & 3 of U2 (+/i op-amp input) should be within
+10 mV of each other with U2 unplugged.  A greater difference indicates
+one of the resistor values is wrong.
+
 TODO List
 ---------
 
@@ -147,6 +168,8 @@ TODO List
     + with datasheet pdfs ?
 [ ] wire correctly for power on reset
     + test with dodgy power on curve (slow power up)
+[ ] unused LM324 inputs
+    + check if its really OK to GND them
 [X] blog post
 [X] README in SVN
     + this file
@@ -157,6 +180,9 @@ TODO List
 [ ] check what happens in overvoltage on input, how can we protect?
 [ ] document test plan
 [ ] get PIC part name right in symbol file
+[ ] meausure the current consumption of the soldered prototype
+[ ] Indicate single point grounding on schematic
+[ ] Note 1% R's on schematic
 [X] make sure we can't stall in RS232 input routine
     + need a way to get around this.....
     + malformed RS323 could cause a hang
@@ -171,6 +197,10 @@ TODO List
     + or can it be spread over cycles?
 [ ] enable PIC watchdog timer
     + how can we test?
+[ ] How repeatable is current sensor?
+    + y intercept (DC offset)
+    + slope
+    + maybe build a few a check
 [ ] make sure all RS232 chars OK
     + how to prog with calibrated clock?
     + check baud rate
diff --git a/wispcar/wispcar.sch b/wispcar/wispcar.sch
index f89a00a5..db323aba 100644
--- a/wispcar/wispcar.sch
+++ b/wispcar/wispcar.sch
@@ -36,7 +36,7 @@ device=LM324
 T 57500 35900 5 10 1 1 180 6 1
 refdes=U2
 T 58000 35600 5 10 0 0 180 6 1
-slot=2
+slot=1
 }
 C 56300 28300 1 0 0 lm324-1.sym
 {
@@ -45,7 +45,7 @@ device=LM324
 T 57000 29100 5 10 1 1 0 0 1
 refdes=U2
 T 56300 28300 5 10 0 0 0 0 1
-slot=1
+slot=2
 }
 C 56300 29300 1 0 0 lm324-1.sym
 {
@@ -194,45 +194,45 @@ value=0.1R 5W
 }
 C 54400 36300 1 270 0 bf-resistor-1.sym
 {
-T 53900 36000 5 10 1 1 0 0 1
+T 54700 36000 5 10 1 1 0 0 1
 refdes=R6
-T 53900 35800 5 10 1 1 0 0 1
-value=1M
+T 54700 35800 5 10 1 1 0 0 1
+value=100k 1%
 }
 C 54400 34900 1 270 0 bf-resistor-1.sym
 {
-T 53900 34700 5 10 1 1 0 0 1
+T 54700 34600 5 10 1 1 0 0 1
 refdes=R7
-T 53900 34500 5 10 1 1 0 0 1
-value=100k
+T 54700 34400 5 10 1 1 0 0 1
+value=10k 1%
 }
 C 56400 36300 1 270 0 bf-resistor-1.sym
 {
-T 55900 36000 5 10 1 1 0 0 1
+T 56700 36400 5 10 1 1 0 0 1
 refdes=R8
-T 55900 35800 5 10 1 1 0 0 1
-value=1M
+T 56700 36200 5 10 1 1 0 0 1
+value=100k 1%
 }
 C 56400 34900 1 270 0 bf-resistor-1.sym
 {
-T 55900 34600 5 10 1 1 0 0 1
+T 56700 34600 5 10 1 1 0 0 1
 refdes=R9
-T 55900 34400 5 10 1 1 0 0 1
-value=100k
+T 56700 34400 5 10 1 1 0 0 1
+value=10k 1%
 }
 C 57500 34900 1 270 0 bf-resistor-1.sym
 {
-T 57000 34600 5 10 1 1 0 0 1
+T 57800 34100 5 10 1 1 0 0 1
 refdes=R10
-T 57000 34400 5 10 1 1 0 0 1
-value=10M
+T 57800 33900 5 10 1 1 0 0 1
+value=1M 1%
 }
 C 58000 36000 1 0 0 bf-resistor-1.sym
 {
 T 58300 36500 5 10 1 1 0 0 1
 refdes=R11
 T 58300 36300 5 10 1 1 0 0 1
-value=10M
+value=1M 1%
 }
 N 54500 36700 54500 36300 4
 N 54500 35400 54500 34900 4
diff --git a/wispcar/wispcar_sch.pdf b/wispcar/wispcar_sch.pdf
index 14817e2b..621c0ca0 100644
Binary files a/wispcar/wispcar_sch.pdf and b/wispcar/wispcar_sch.pdf differ