INFICON PSG55x ATM to Medium Vacuum Gauge (DeviceNet) - Manual (Page 24)

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tira58e1-a (2012-03) PxG5xx.cp
All Data Type attributes use the enumerated values integer or float.
The Data Type value will be set automatically based upon the first valid I/O con-
nection established by the device.
If no established I/O connections exist, which include an attribute from this object,
then the Data Type attribute is settable provided that the object is in the Idle State.
If the data type is set to integer and the data unit is chosen with Counts a pres-
sure level can be calculated back with (e.g. in mbar):
20
3511
1
2
10
int
−
=
eger
Value
mbar
P
Using data type integer in combination with a pressure unit (mbar, Torr
or Pa) will obviously not produce reasonable values below 1.
The output of the data type "float" in combination with the data unit
"Counts" is in a fixpoint format with 1 bit for the sign, 11 bits for the
integer and 20 bits for the decimal part. To convert it into a normal float
format the output has to be divided by 2
20 .
The Data Unit is only settable in the IDLE state.
An S-Analog sensor object instance derives a reading from a physical analog sen-
sor. The reading is converted to the data type and units specified for the value
attribute.
A bit mapped byte which indicates the Alarm and Warning Exception status of the
object instance. The following definition applies:
Bit Definition
0 High Alarm Exception: 0 = cleared 1 = set
1 Low Alarm Exception: 0 = cleared 1 = set
2 High Warning Exception: 0 = cleared 1 = set
3 Low Warning Exception: 0 = cleared 1 = set
4 Reserved
5 Reserved
6 Reserved
7 Reserved
This attribute specifies what value will be held in value for states other than exe-
cuting. The purpose of this mechanism is to allow other devices, who may be using
this value to transition to (or remain in) a safe state in the event of this device
transitioning to a FAULT, IDLE, or ABORT state. The following values are defined:
Attribute value State
0 Zero
1 Full
scale
2 Hold last value
3 Use safe value
For safe state set to use safe value, this attribute holds the value to which the value
attribute will be set for object instance states other than executing.
4.4.3.2 Semantics
Data type
Data unit
Value
Status
Safe state
Safe value