Specifications

MI 611-211 – October 2005 3. Operation
18
NOTE
A change in the Primary Sensor, Resolution, or Scale requires a calibration.
Next, under DISPLAY SECOND, you can configure the secondary display to show the absolute
value of the measurement in millivolts, the output in 4 to 20 mA, or the temperature.
Config Output
(Refer to “Structure Diagram 1” on page 38.)
This section of the structure first asks you to specify the
MODE, referring to the communications
and measurement output. If your transmitter was specified with analog output only (870ITPH-
A), specify ANALOG. If your transmitter was specified with I/A Series communications
(870ITPH-F), specify ANALOG if you want to have a 600 baud digital signal superimposed over
an analog 4 to 20 mA signal, or specify
DIGITAL if you want to have a 4800 baud digital signal
only.
If you configured the mode as
ANALOG, you will be asked, under OUTPUT ANALOG, to
specify the 4 to 20 mA output to represent the uncompensated (ABSOLUTE) measurement, the
temperature compensated MEASUREment, or the TEMPerature.
If you configured the mode as DIGITAL, the 4 to 20 mA output will be fixed at 12 mA.
Next, under OUTPUT RANGE, enter the MINimum (4 mA) and MAXimum (20 mA) range
values for the output just specified. Specify between +2000 and -2000 mV for ABSOLUTE, in °C
or °F for TEMPerature, or in measurement units (pH for pH, mV for ORP, ppm for ISE) for
MEASURE. To configure the output as reverse acting, enter higher value as MINimum and the
smaller as MAXimum.
NOTE
1. 1. The units for temperature,°C or °F, are specified in the section titled “Config
Temp” on page 20.
2. 2. A change in OUTPUT ANALOG will cause the OUTPUT RANGE to default
to 0.0 and thus new MIN and MAX values must be entered.
Lastly, you can specify a fail-safe signal for all transmitter errors and for critical sensor diagnostic
errors. Specify ON to specify a fixed output when in a failed condition. If ON is selected, further
specify the
DC mA output between 3.8 and 20.5 mA. The default value is 3.8 mA. If you want to
have this signal outputted with ±0.5 mA pulse (as shown below) for greater visibility on a chart
recorder or data display, specify
ON as explained above and then go back and specify PULSE.
The
OFF selection is not functional in the current versions of firmware. Any sensor diagnostic
that has been set to
ENABLE (see “Config Diags” on page 26) causes the output to go to the fail-
safe
DC mA signal. If sensor diagnostics are enabled, it is important to set the fail-safe DC mA
value to an acceptable safe output level. If you do not want the output to respond to some or all of
the sensor diagnostics, then you must set the selected diagnostics to
DISABLE in the Config
Diags menu.