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IM-ENG-116/GB
6.3 Supply port
Supply voltage: 24 Vdc (-15%, +25%)
Supply current: 20 Vdc 32 mA (typical, RS485 quiescent)
24 Vdc 28 mA (typical, RS485 quiescent)
30 Vdc 23 mA (typical, RS485 quiescent)
Protection: internal fuse, not user-serviceable
6.4 Signal port (HART)
Channel number: 32 signal loops
DC-isolation: dual-capacitor isolation on each loop
Allowed common mode voltage: up to 30V
Differential mode clamping: +/- 5.2V (for transient or AC signals)
Receive signal range: 0.12 Vpp < signal < 1,5 Vpp
Receive impedance magnitude: > 5000 Ω
Carrier Detect levels: signal > 0.12 Vpp — CD asserted
signal < 0.080 Vpp — CD not asserted
Transmit signal amplitude : 200 mV (200 Ω load, typical)
500 mV (500 Ω load, typical)
200 Ω load — 150 mV < signal < 250 mV
Carrier stop time < 10 bit time
Device connection type: DC-isolated bus device
Impedance level type: High Impedance device
Data link type: Primary or Secondary Master (configurable)
Field multi-drop support: available on request
For additional, more detailed HART-related specifications, please refer to the HART FSK Physical Layer
Specification Rev.8.0 available from the HART Communication Foundation (HCF_SPEC-54), which the Mux 2700
module is generally compliant with.
Notes :
• To minimise input capacitors size and to get an higher output signal level, the Hart signal transmit section is based
on a current generation technique. For this reasons, the output signal level is proportional to the external load,
which should not exceed 500 Ω to avoid possible cross-talk or saturation problems.
• The specified transmit-signal amplitude is a DC value measured at the centre of a waveform semi-period.
• To maximise allowed cable length and to avoid noise problems, you should avoid to connect to the MUX HART
low impedence devices < 250 Ω.
6.5 Serial port (RS-485)
Line type: RS-485, differential pair plus GND
Line speed: 9600 Baud or 19200 Baud
Line topology: multi-point, master-slave connection
Device type: slave (up to 31 slave Mux can connected to a single master)
Slave addressing range: 1 to 31 (0 reserved)
Protocol type: H-Port (HART based)
Master device: Maintenance Workstation (MW)
Warning !
A suitable RS-232 to RS-485 converter is required to connect the port with a standard PC (see Fig. 6).
As for RS-485 line detailed specifications, please refer to the relevant standard.
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