Baumer TA202 - Handbuch (Seite 9)

TA202
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Supplementary operating manual
For electronic tachometer
TA202 Program 01
1. General
The serial interface can fulfil the same functions as tachometer display and keyboard. Via interface data can be
called off or programmed parameters can be altered. Normally the tachometer is PC- operated when working
with interface, that’s why in the following we call the external device shortly PC. However, any other device with
similar characteristics may be used.
2. Transfer protocol
Data transfer is realized sign by sign in ASCII-Code. Each sign consits of 8 Bit.. Bit No. 8 is the so-called Parity
Bit, in case of „no Parity„ Bit No. 8 is always transferred as zero. Each time on request by PC, the tachometer
transfers via serial interface the corresponding reply, provided the data transfer was effected correctly.
The transfer of signs is released by the start sign<STX> and finalized by the stop sign<ETX>. In addition, after
the <ETX> the tacho is transmitting <CR> (carriage return) which allows reading in of a complete data block with
one command (in standard computer language as BASIC).
<STX> is followed by an address assigned to the tachometer. Thus, the tacho can be specificly addressed in
serial network. After the address the line (position) to be read out or programmed is defined. In case of a
programming command it is followed by „P„ (programming) and the data (parameters).
The protocol is split into 3 groups as outlined below:
a) Reading of storage places (READ command):
<STX> address line <ETX> [<CR>]
b) Programming of storage places (WRITE command):
<STX> address line P data <ETX> [<CR>]
c) Special commands:
<STX> address parameter <ETX> [<CR>]
<STX> Start of Text (02Hex)
Address 00..99 (device address)
Line 01..XX (see operation plan)
P Programming command
Data Programming data
Parameter Special commands
<ETX> End of Text (03Hex)
<CR> 0DHex (control sign "carriage return")
"CR" not imperative (optional) but always sent back
by the tachometer.
Example:
General <STX> address line <ETX> (address=35; line=02)
Ascii <STX>3502<ETX>
Hex 02H,33H,35H,30H,32H,03H
Important! The space between the individual signs of each command serve only for better depiction and have
to be entered by PC without space. Control signs (inferior 20 Hex) are depicted in paranthesis.
Should the PC send out a wrong protocol, the error message is returned by the tacho provided it
still remains in responsive status (see chapter „error messages„ on page 6).