Loop powered operation
Loop powered transmitters use the drop in voltage across the
outputs to generate power for the electronics. The 931U-C9A2C-
OP requires a 10-40 V drop to operate correctly. Using a power
supply that provides this voltage drop will comply with the
instrument's UL/CSA listing.
Receiving devices are placed in series with the 931U-C9A2C-OP
and introduce additional load resistances into the loop. The total
loop load for a 4-20 mA loop powered by supply voltage V
is
s
R
= 50 x (V
-10).So, for example, a 931U-C9A2C-OP powered
loop
s
from a 24 V DC supply can drive a 700 Ω loop load.
• Installation
WARNING
• Disconnect power prior to installation
• Installation only by Qualified personnel
• Follow all applicable local and national electrical codes
• Do not cover the case holes.
• Case front should be closed in normal operation.
• Take care to avoid touching the internal components when the
front panel is open.
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