TM-2025 & TM-2030 Serial Data Output

This document describes the serial data
output from the TM-2025 or TM2030. For
technical users.
see last paragraph.For TM-2030
What data is available:
The form of the serial data:
More precise description:
Accessing the data:
The following "real time" data are available:
The "filtered
volts and amps" are highly filtered (slowly varying) versions of "Volts 1" and
"Amps" with filter time constant of about 5 minutes. The following data are
NOT available by the serial data: The Logged data (History data) from the
TriMetric and the programmed data that you have entered into the TM-2025.
The TM-2025 real time data (no logged
data) comes out from Pin 4 on J2 as a constantly repeating ASCII data
stream at 2400 baud. (The usual: 8 bit, parity none, stop bits=1) For example,
the amps and watts show as “A=3.3, W=36.7” The output "high" volts
(+5V) is "mark" or "idle" state. "Start bit" (logic 0), is about 0 volts.)
Refer to page 2. The data emerges
between Pin4 and Pin3 (of J2) as a signal with +5V amplitude, with 0 volt
reference at Pin3. It is recommended however to use "G1" as the "ground"
("0V") reference (as shown) instead of Pin 3, which is about +0.6 volts with
respect to pin 3. G1 is the pin on the 5 pin terminal block that also must be
connected to the minus side of the battery system, as indicated in the
TM2025 Installation Instructions. With reference to G1, the serial data signal
at pin 4 will go from -0.6V to +4.4V signal.
The output (+5V peak) from the serial out comes directly between
pins 3 and 4 of J2, which come from the output pins of a Microchip
PIC16F884 microcontroller. However current from here should be limited to
5 ma or so because the power source does not have high current capability
The MAX232 shown inverts the data for a proper RS232 signal.
This document shows two ways to access the
data. The top example on page 2 shows how to convert the data suitable for
output to RS232 port for an older computer or to a USB to RS232 converter.
The bottom example shows how it could be interfaced to another
microcontroller for further analysis or processing. The purpose of the signal
diode (1N4148) and resistor is to shift the level up slightly so it goes from 0 to
5V instead of -0.6 to 4.4V.
Volts 1, Volts 2, Filtered Volts 1, Amps, Filtered Amps, Amp-hr, Percent
Full, Watts, Days since charged, days since equalized.
If you want to send it to your computer
Do you want to interface to a microcontroller to use the data
to use or control in some other manner?
This will work with theTM-2025 or newer TM-2030
For the TM-2030:
edge
to read with a serial data
reading program, or perhaps to access with your own program--
The schematic on page 2 shows how to convert it to a form that can
be sent to a (now old fashioned) RS232 port on your computer, such
that was commonly used ten years ago. Most computers how
have only a USB port-- so to use that you will need to connect the
"RS232 output" to a USB to RS232 converter to convert it to your
USB connection on your computer. These are available from Radio
Shack, or other company selling computer accessories. The
"MAX232" shown in the schematic level shifts, and inverts the data
in a form suitable for the RS232 terminal, or for an RS232 to USB
converter.
When connected to a computer RS232 port, you can view the data
on your computer screen to check that it is working by using the
Windows program called "Hyperterminal" or another much easier to
use and much better documented program called "Docklight" which
is available for free on the web. However if you want to get a version
that allows you to save your settings you would need to pay 50
euros for the non free version. This would not be necessary to just
check to see that it is working--but in my opinion this program is
worth the money if you use these much.
Then the bottom
drawing on page 2 suggests the interface to get a serial input
which goes from about 0 to 5 volts. As mentioned before, 5 volts
represents the "idle" state, and 0 volts is the start bit level.
– the
drawings below show the TM-2025– but the only difference is
the output pinouts for the TM-2030.
Although J2 on the TM-2025 looks quite
different from on the TM-2030, (the TM-2030 uses a RJ-11 type
“phone connector”) the pin connection numbers are the same.
The numbers are ordered in an obvious sequence. It only
remains to tell you which one is “pin 1”. As you look at J1 on the
circuit board, pin 1 will the one closest to the of the circuit
board--pin 4 is 4 away from the edge.