Supported services
•
5 different mandatory RX-NMT objects for the state-management (see CiA 301)
•
Heartbeat-producing with indication of the actual state and bootup-frame
•
1 Tx-PDO for measuring values
•
37 different SDOs in the Object dictionary, two of them manufacturer-defined, see
EDS
Interpretation of the 1
st
Tx-PDO
After Bootup the device is in the Preoperational state. In order to let the device send the
1
st
Tx-PDO, the „Enter Operational state NMT“ must be transmitted to the device. If all
other send-conditions are met (see below), the following PDO-frames are sent, in time-
order from left to the right:
Analog Input Process Value
A.Input Status Alarm Status
LSByte
Byte 1
Byte 2
MSByte
Byte
Byte
In the default configuration, the Analog Input Process Value ia a Signed-Integer 32
number, which must be interpreted as following, to get scaled measuring-values:
Measuring value = Analog_Input_Process_Value_Raw_Value /
(10^Analog_Input_Decimal_Digits)
So, for interpretation the object 6132h (Analog_Input_Decimal_Digits) must be read once
and the A.I.Process_Value_Raw_ Value must then be divided by the power of the
Analog_Input_Decimal_Digits to the base of 10.
With the object 6126h the Analog Input Process Value can be scaled, to customize it to
the application requirements. By writing to 6126h the Analog_Input_Decimal_Digits may
get altered in the background, so after writing to 6126h the object 6132h should be read
again. Changing the Physical Units (Object 6131h) hasn't any influence on 6126h and on
6132h.
Future versions (from firmware version 1.4 on) will be able to transmit the Analog Input
Process Value as a float, scaled directy to physical units, so that this lavish interpretation
won't be necessary anymore.
The Analog Input Status Byte contains the following flags:
Bit 0 (LSBit): (still reserved, =0; future versions: sensor broken)
Bit1: Positive overflow of the measuring value
Bit2: Negative overflow (=underflow) of the measuring value
Bits 3..7: =0
With the GSV-2CANOpen, the Alarm Block is implemented as the threshold switch,
whereby the measuring value is compared to a threshold and the threshold switching
output is set on or off. The status of these switches are part of the Alarm Status.
The Alarm Status Byte contains the following flags:
Bit 0 (LSBit): Threshold switch 1 activated
Bit 1: Threshold switch 2 activated
Bits 2..7: =0
Send-conditions for the 1
st
Tx-PDO
•
State = operational AND
•
PDO = valid (Object 1800.1 Data-Bit 31 =0)
AND if Transmission-Type (1800.2) = 255 (default setting):
ME-Meßsysteme GmbH, Neuendorfstr. 18a, D-16761 Hennigsdorf
54
Phone 03302 78620 60, Fax 03302 78620 69,
,
www.me-systeme.de/en
Содержание GSV-2AS
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