Baumer BA DACU 820 - Handbuch (Seite 15)

DACU_820_BA_V2_1M.doc 29/40 Baumer Electric AG
Frauenfeld, Switzerland
5.7 80% test
This function makes it possible to check the measuring chain without a sensor being connected, and
can thus be used to limit errors. The amplitude is approx. 8V (80%FS).
Example:
t
t
t
Operate
+8V
1
1
0
0
-8V
80%-Test
Signal out
CH1=CH2
5.8 Change polarity
If the polarity of the output channel is not as favored it can be changed by the DIP-switch
(DIP-1
channel 1, DIP-2 channel 2).
5.9 Identification of charge amplifier
The charge amplifier can be identified on the basis of a code on the connecting plug. For this purpose,
a defined voltage must be applied to pin 13.
On pins 11, 12 and 24, the code corresponding to this type can be read out.
Code for DACU 820:
Code 2 Code 1 Code 0
Level 0 1 0
Meaning: 0 Supply GND
1 Code Supply +
DACU_820_BA_V2_1M.doc 30/40 Baumer Electric AG
Frauenfeld, Switzerland
6 Serial Interface
6.1 Description
The DACU 820 has an implemented serial interface RS232. With the corresponding commands it is
possible to set the Charge Amplifier and to read out the output signals (CH1 und CH2).
Transmission format
The Information are transmitted serially with following format:
• 1 Start-Bit
• 8 Data-Bits (the low order first)
• 1 Stop-Bit
• Transmission rate: 9’600 Baud (Default) – 115’200 Baud
That results 10 bit per transmitted character.
6.2 Data format Master
6.2.1 General
The command starts with the character STX (02h), followed by a command and a fix number of
parameters and finally a checksum. After checking the checksum and the execution of the
command, the DACU returns an ACK (06h) back to the master.
The message of the master has always following format:
ASCII ASCII ASCII ASCII
Start character command n-Parameter Checksum
Checksum: Sum of all ASCII-characters, always 1Byte long (lowest order 4 Bit in ASCII converted).
6.2.2 Remote Function
Enables and disables the remote function of the DACU. When the remote function is enabled, the
control functions (Operate, Range, Test..) are disabled.
An interruption of the power supply or a power up causes the disabling of the remote function. After
each enabling the settings are loaded from the E
2 Prom.
Command data structure:
Example: Remote active
Start command Parameter Checksum
02h 61h 31h 34h
STX a 1 4 (94h)
Parameter 0: Remote inactive, control by the Sub-D connection
1: Remote active, control by RS232
Note
After each power up of the DACU the transmission rate is set on 9’600 Baud!
The baud rate can be set as explained under 6.2.9.