INFICON PEG100-P Medium to Ultra-High Vacuum Gauge - Manual (Page 6)

2.2.1 Meaning of PEG100-P (slave) input and
output data
2.2.1.1 PEG100-P output data
(output data from the master’s view point)
The following two 2 bytes are sent to the device:
Output data
———————————————–
Byte 0
Bit 7 not used
Bit 6 not used
Bit 5 not used
Bit 4 not used
Bit 3 not used
Bit 2 not used
Bit 1 Control Bit
Bit 0 Control Bit
———————————————–
Byte 1 not used
Semantics
Byte 0 / Bit 0 and Bit 1
The high voltage could be switched on by the digital
inputs (Pin 7 or Pin 8) at the FCC 68 plug or directly by
a profibus command. The input has to be selected by
these two bits.
Bit 1 Bit 0 Meaning HEX-
Value
————————————————————————–
0 0 Digital Inputs active 0
1 0 Fieldbus active, High Voltage OFF 2
1 1 Fieldbus active, High Voltage ON 3
2.2.1.2 PEG100-P input data
(from master’s view point)
The input data contain the following information: status
information and measurement results (as 12-bit values).
Input data
—————————————————————–
Byte 0
Bit 7 Status bit
Bit 6 Status bit
Bit 5 Status bit
Bit 4 Status bit
Bit 3 Measurement value: Bit 11: MSB
Bit 2 Measurement value Bit 10
Bit 1 Measurement value Bit 9
Bit 0 Measurement value Bit 8
———————————————–——————
Byte 1
Bit 7 Measurement value Bit 7
Bit 6 Measurement value Bit 6
Bit 5 Measurement value Bit 5
Bit 4 Measurement value Bit 4
Bit 3 Measurement value Bit 3
Bit 2 Measurement value Bit 2
Bit 1 Measurement value Bit 1
Bit 0 Measurement value Bit 0: LSB
Explanation
Byte 0 / Bit 4 - Bit 7 - Status messages
Bit 7 Bit 6 Bit 5 Bit 4 meaning HEX-
Value
———————————————————————————
1 0 1 0 High Voltage OFF A
1 1 1 0 High Voltage ON, E
No Ignition
1 1 0 0 High Voltage ON, C
Measurement Value ok
0 1 1 0 HV on, but no ignition 6
after 1 min of HV on
Measurement values - representation
The measurement value is given as a 12-bit value. Byte
0/Bit 3 represents the MSB, byte 1/Bit 0 the LSB.
How to calculate the measurement value
The measurement values are calculated according to the
following formulas in the corresponding measurement
units.
Calculation formula in unit „mbar“
pressure p / mbar= 10
(output value / 500 - 9.5)
A special pressure’s value is calculated with the follo-
wing formula:
value = 500 · (log (p / mbar) + 9,5)
Calculation formula in unit „torr“
pressure p = 10
(output value / 500 - 9.6249)
A special pressure’s value is calculated with the follo-
wing formula:
value = 500 · (log (p / Torr) + 9,6249)
Calculation formula in unit „Pascal“
pressure p = 10
(output value / 500 - 7.5)
A special pressure’s value is calculated with the follo-
wing formula:
value = 500 · (log (p / Pa) +7,5)
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tina15e1-a (0206) PEG100-P.ga