Page 26 • MN06150 ║ Issue/Rev. 0.7 (9/18)
Section IV – Diagrams
Figure 13. Analog Inputs; Resistance (RTD) / 4-20ma
If using two twisted pairs of wires, RTD+ and RTD- should be wired with one twisted pair. Sig+ and Sig– should be
wired with another twisted pair.
This input requires a four-wire connection to a platinum sensor with the following specification:
1. 100
Ω
@ 0 Degrees Celsius.
2. 0.00385
Ω / Ω /
Deg. C., DIN 43760, BS1904, or IPTS 1948 Temperature Coefficient.
The 4-20mA input is not isolated from the processor and main power (CN9-2 is electrically connected to “common”).
The 4-20mA input can be programmed for the function required by the application. The analog inputs are also scaleable
through the I/O Configuration Menu of the unit. The inputs should be wired with shielded twisted pairs of wires of
18 to 24 gauge.
Note:
Due to the fact that the common for the 4-20mA input on the microLoad is not isolated, you cannot connect it in series with another microLoad
to share the 4-20mA output signal from a single device (i.e. temperature probe, density, pressure transducer). The reason for this is that if the com-
mons for the 4-20mA inputs on the separate microLoads have the same potential and are connected in series, one of the inputs will be by passed
and cause it to produce a zero reading. This would then give an appearance that the second 4-20mA input in the series circuit was defective.
Summary of Contents for Smith Meter microLoad.net
Page 13: ...Issue Rev 0 7 9 18 MN06150 Page 13 Section IV Diagrams Figure 3 Opening microLoad net ...
Page 29: ...Issue Rev 0 7 9 18 MN06150 Page 29 Section IV Diagrams Figure 16 RS 232 Shared Printing ...
Page 30: ...Page 30 MN06150 Issue Rev 0 7 9 18 Section IV Diagrams Figure 17 RS 485 Shared Printing ...
Page 37: ...Issue Rev 0 7 9 18 MN06150 Page 37 Section IV Diagrams Figure 24 AC Digital Outputs ...
Page 40: ...Page 40 MN06150 Issue Rev 0 7 9 18 Section IV Diagrams Figure 26 Sample Application Worksheet ...
Page 41: ...Issue Rev 0 7 9 18 MN06150 Page 41 Section IV Diagrams Figure 27 Sample Application AC Wiring ...
