IM 12A06S01-00EN-P
37
7.1.8 Unit conversion
• Temperature unit
The temperature can be set in Celsius (°C) or Fahrenheit (°F). If the unit is changed by the
HOST, the following values are also recalculated automatically to the new unit:
o Manual temp.
o Reference temp.
o Temp. coefficient
o Temp. ranges in the matrix
7.1.9 Calibration settings for Conductivity/Resistivity
For calibration it is needed to set acceptance limits, see Appendix 8 for details. Settings
have to be done by HOST system.
•
Limits and timing
o c.c. High/Low limits:
During calibration, it is checked if the new c.c. exceeds these high and low limits.
o Step Range:
Set the range over which the stability of a measured value is checked. If variations of a
measured value over the stabilization time are within this set value, the measured value is
judged to have stabilized.
o Stabilization time:
During calibration, the stability of the measurement value is constantly monitored. When
variations of the measurement value during this stabilization time are within a value set
in Step Range, the value is regarded as being stable. If the measurement value does not
stabilize within the time set for stabilization (default 5 seconds), the calibration procedure
is aborted.
o Calibration interval:
Set the interval in which a new calibration must take place. If the interval set here is
exceeded, the SA11 will notify according to the setting in “Calib. time exceeded” in the
error configuration.
•
Standard solution (buffer) select
Calibration is made using standard calibration solutions. Yokogawa recommends the
standard buffers directed by DIN 53-779 for highest accuracy: 1.000M KCl, 0.100M KCl,
0.010M KCl and 0.005M KCl.
The standard buffer solutions can be found in Appendix 5.
7.2 Communication setup
The SA11 is a slave device communicating with a HOST system using MODBUS protocol.
For correct communication the following settings can be made:
•
MODBUS address
The MODBUS address (Slave ID) is default set to 1, but can be set by HOST system to
another address in between #1 and #247.
•
Serial profile
MODBUS is an application layer messaging protocol which provides client/server
communication between devices connected on different types of buses/networks. The
SA11 is able to communicate with two predefined serial profile settings, to be selected by
the HOST system, which is default set to 1:
1. 9600 bps, 8 bits, even parity, 1 stop bit
2. 19200 bps, 8 bits, no parity, 2 stop bits