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3.0 OPTIONS
The Model 1250B may be configured with one or more options. This section
describes general use of each option, including wiring and programming for each option.
3.1 Analog Output Option “-0”, “-1”, “-2”, “-4”,”
The analog output on the 1250B may be used to feed position information to a remote
monitoring system such as SCADA, or a remote indicator such as the INCON model
1511-LTC. In the Scaled Modes, the span of the analog output must be programmed. In the
Segmented Modes, the analog output automatically spans between the highest and lowest
taps.
Wiring:
The 4-20mA analog output option must be wired with an external power supply of
10.0 to 24.0 volts DC in series with the analog output current loop (See Figure 1.3). The
INCON Model 1945 is available for this purpose. All other analog output options are self-
powered. Refer to Table 3.1 below for analog output load limits.
Table 3.1 Analog Output Load Limits
Analog Output:
Load Minimum
Load Maximum
0 to 1 mA
Zero Ohms
10K Ohms
+/- 1 mA
Zero Ohms
10K Ohms
0 to 2 mA
Zero Ohms
5K Ohms
4-20 mA
Zero Ohms
400 Ohms with 10
volt power supply
4-20 mA
Zero Ohms
1100 Ohms with 24
volt power supply
3.1.1 Programming the Analog Output Span
The upper and lower limits of the analog output must be defined in the Scaled Modes.
Use the
OP 5, An L, ANAMIN
command to set the lower limit of the analog output. Use the
OP 6, An H, ANAMAX
command to set the upper limit of the analog output. The analog
output will span automatically between these two limits. The output will be at its minimum
output when the displayed value is at the lower limit. The output will be at its maximum
output when the displayed value is at the upper limit.
Note:
If the presence of high voltage AC “ripple” is found on the analog output terminals, it
is generally not a problem with the 1250B itself. Check the isolation of all field wiring with
respect to earth ground. All wiring should be completely isolated from ground. See section
3.2 Input Isolation Option. Contact INCON Technical Service for assistance if the problem
persists.
3.2 Input Isolation Option “-I”