From: "Shawn M. Waggoner" <[EMAIL PROTECTED]>
Reply-To: ElectricMotorcycles <[email protected]>
To: "'ElectricMotorcycles'" <[email protected]>
Subject: Re: [ElectricMotorcycles] photos of the dash
Date: Wed, 30 Nov 2005 13:13:07 -0500
>I was thinking of doing something along these lines as well. I have a
>couple of BS2's laying around and enjoy playing with them. The biggest
>problem I see going this route is that data from the controller is on the
>motor side of things (I think, but I'm not positive). Generally when we
>look at volts and amps it is to keep the battery pack in shape, so we
>really
>need to look at what is going on on the battery side. Now that I think
>about it though, I be making an incorrect assumption about the data the
>Alltrax provides. Perhaps I need to strap the old laptop on and go for a
>ride.
Hi All,
The Alltrax controller will monitor the following:
Throttle Position
Controller Temp
Battery Voltage
Output (motor) Current
Battery Current
Error Flags
The Alltrax application allows you to monitor these or write them to file.
That's great for application where you can take your laptop along...
I guess you would need to know what the values are and how to read them
from
the controller to input them to the 'dash'. Does anyone know the values,
codes and value constants for using the data from the Alltrax directly?
--
Shawn M. Waggoner
Yep we have that straight from Damon Crocket at Alltrax. Actually looking
at this you can see what the Microprocessor knows about. Battery current is
apparently a derived figure from the motor current.
damon
The following notes are excerpts from the source code for the controller.
You software guys can most likely figure it out from here as its terribly
simplistic.
The controller is a slave, it only speaks if spoken to, and only then if it
understands the command, checksum is correct and so on. Youll have to poll
the controllers RAM for data. You can write memory locations in flash and
eeprom, but all it will do is cause us both headaches. Ive identified the
commands in this protocol so you dont have to tinker around trying to find
them, but do us both a favour and leave flash/eeprom alone. Call Alltrax
for support.
Serial protocol is RS-232, 9600 baud, 8 data bits, no parity, 1 stop bit, no
handshaking. Protocol only uses a source/target I.D. and checksum to
validate incoming information, it wasnt meant to live on a network. The
controller understands 6 commands, as detailed below, but really all you
should be doing is reading RAM. The target processor in the AXE line is a
PIC16F873, in the DCX it is a PIC16F876.
AXE communications Spec. All references relative to motor controller.
;Communications Packet Protocol
;
; Recieve Packet Format
;
; Name Size Definition
;
; source/target 1 byte Windows App is 5h, controller
is Bh
; command 1 byte command function to controller
; data1 1 byte
; data2 1 byte
; data3 1 byte
; data4 1 byte
; checksum 1 byte OVERFLOWED SUM OF PREVIOUS SIX BYTES
;
;
;
;Command byte definition
;
; This is the instruction set for communicating with the controller.
; 00h = read byte of program (flash) memory
; 01h = write byte of program (flash) memory
; 02h = read byte of EEPROM memory
; 03h = write byte of EEPROM
; 04h = read 3 sequential bytes of RAM
; 05h = reset
;
; 04h = READ RAM - This command fetches three sequential bytes of
information
; from RAM (variable) memory and sends it to the Windows
host.
; variable locations are organized in order to minimize
; the number of read cycles needed to refresh data.
;
; Read RAM Packet Format (sent by PC)
;
; source/target : 5Bh (windows app is host,
controller is target)
; command : 04h (read three RAM bytes)
; data1 : ADDRESS, in hex.
; data2 : DON'T CARE
; data3 : DON'T CARE
; data4 : DON'T CARE
; checksum : OVERFLOWED SUM OF PREVIOUS SIX BYTES
;
; After decoding the packet, the controller shall assemble the
following
; information and reply to the Windows Host:
;
; Response Format (sent by controller)
;
; source/target : B5h
; command : 04h
; data1 : ADDRESS (start address of three sequential
bytes)
; data2 : data @ ADDRESS
; data3 : data @ ADDRESS + 1
; data4 : data @ ADDRESS + 2
; checksum : overflowed sum of 6 previous bytes
;
;
;
;
; 05h = RESET: This command causes the program to goto the START location
and begin anew. The complete 7 byte protocol must be sent, but all data is
dummy.
The following are RAM locations you can read to get measurement data. High
and low bytes are in successive locations, thus you can fetch both high/low
byte with one read cycle.
THROT_POS EQU 0x20 ;8 bit Throttle position, 00h = off, FFh
= wide open
DIODE_TEMP_L EQU 0x2C
DIODE_TEMP_H EQU 0x2D ;Internal Controller temperature,
;
BATT_VOLT_L EQU 0x39 ; 0.1025 volts per bit.
BATT_VOLT_H EQU 0x3A
SHUTDOWN EQU 0x3B ;Error status, any bit set, NO
PWM output.
OUTPUT_CURR_L EQU 0x60 ; IOUT = 1A/BIT, 0 - 1023A
OUTPUT_CURR_H EQU 0x61 ; high byte
Battery current may be calculated as a percentage of output current,
assuming continuous motor currrent. Convert THROT_POS to decimal, then
Ibattery = (THROT_POS / 256) * OUTPUT_CURR_H,L
Temperature is measured with a Kelvin sensor, temp = 2.73V @ 0C Thus there
is an offset at 0C = 559 counts. Temperature slope = 2.048 counts / deg C
(positive tempco.)
Please keep this confidential to your uses, its dissemination would only
serve to cause me headaches or excessive warranty hassles.
Cheers,
Damon Crockett
Engineer
Alltrax, Inc.
7-26-05
