Badger Meter SRD/SRI Valve Positioners - Manual (Page 10)

System Configuration
Version 4…20 mA without communication: Connection as traditional point-to-point connection according to the known
regulations of the measuring & control techniques
HART version: When using ‘Communication’ (an AC signal which modulates on the 4-20 mA signal), make sure the
connected outputs, buffer amplifier and barriers are compatible with the frequency ranges used In addition to the load,
the AC impedance requirements must be met Therefore, it is recommended that only the specified amplifier, barrier and
configuration device be used
To prevent crosstalk between lines and reduce disturbances through electromagnetic influences, use twisted-pair shielded
lines with a diameter of AWG 22…14 (0 3…2 5 mm 2 ) and a maximum capacity of 100 pF/m
The line capacities and connected devices may not exceed the maximum values listed for a particular HART protocol
All components that are connected to the SRD in an explosion hazardous area require an Ex-Approval The applicable limit
values must not be exceeded Comply with the limit values when connecting additional capacitances, inductances, voltage or
current sources
Summary – Hart and 4…20 mA without Communication
Page 10 August 2014 POS-UM-00010-EN-03