Emerson PACSystems RSTi-EP - 5.20 SSI Encoder Interface Module EP-5311

User Manual Section 5
GFK-2958L May 2021
Detailed Description of I/O Modules 254
5.18.6 Process Data† Outputs EP-5212
Byte
Format
Name
Bit
Function when
edge 0-1
Remark
QB0 ... QB3
Double
word
Channel 0:
Measurement cycle
period
Channel 0: Preset value of
the measurement cycle
period (23 Bit)
QB4 ... QB7
Double
word
Channel 1:
Measurement cycle
period
Channel 1: Preset value of
the measurement cycle
period (23 Bit)
QB8
Word
Channel 0:
Control word
QX8.0 - QX8.7
reserved
QB9
QX9.0
Measurement start
QX9.1
Measurement stop
QX9.2 - 9.7
reserved
QB10
Word
Channel 1:
Control word
QX10.0 - X10.7
reserved
QB11
QX11.0
Measurement start
QX11.1
Measurement stop
QX11.2 - 11.7
reserved
†
Internal process data mapping with data format Standard. Depending on the fieldbus specification and the data format
of the communicating fieldbus components the bytes and/or words can be reversed during data transfer.
5.18.7 Function Frequency Counting
Defining the Measurement Cycle Period
The length of measurement cycle period has to be defined for each channel within the
output process data. As the 23-bit value has a resolution of 1
μ
s, values between 1
μ
s and
8,388,607
μ
s can be defined. The measurement cycle period must be long enough to detect
at least one rising edge.
Setting of Input Filter
In order to suppress any disturbances a digital input filter can be set for each channel via the
Parameter Input filter (refer to Section, Modifiable Parameters for EP-5212).
Start Measurement
Setting of Bit 8 in the control word of each channel starts the cyclic measurement.