23
SPM Flex Gas Detector
4-20 mA wiring
4-20 mA output is a three-wire connection that is configurable as sink, source, or
isolated (isolated is the default), as shown in these following figures� Use a hex
key to remove the wiring cover for access to the terminals� There must be a 200-
600-ohm load on the 4-20 mA line�
To ensure adequate resolution to overcome tolerance in the 4-20 mA reading, set
the full scale at an appropriate level� The SPM Flex issues a fault if the measured
4-20 mA reading is more than 0�8 mA (5% full scale) off from the expected drive
value�
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Figure 13. 4-20 mA sink conguration
Figure 14. 4-20 mA source conguration
Figure 15. 4-20 mA isolated conguration (the default)
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