DRAFT - 11 December 2014
DRAFT - 11 December 2014
4
DRAFT - 11 December 2014
INM MTL4850_54 Rev4
The second alternative - see Figure 2.3 - is to use one of MTL's HART connection units:
• HCU16
16-channel analogue input/output
• HCU16AO
16-channel analogue output with HART filters
and link to an HMP-HM64 HART interface, which can accommodate any combination of four of
these connection units.
The HMP-HM64 is a compact interface between the connection units and the maintenance
system. Up to 32 of these can be daisy-chained on an RS485 link to a PC runnning HART
maintenance software, making a total coverage of 2016 channels. See Sections 4.2 to 4.5 for
details.
The final method considered here consists of two backplane options.
• 16-channel backplane CPH-SC16 and CPH-SC16R
• 32-channel backplane CPH-SC32 and CPH-SC32R
Both backplanes accommodate 16 MTL4500 Series IS isolator modules and an MTL4850 or
MTL4854 multiplexer module.
The CPH-SC16 backplane is designed for MTL4541 single channel isolators and has 16 field terminals,
while the CPH-SC32 has 32 field terminals for MTL4544/4544A dual channel isolator modules.
RS485 ports on the backplanes enable them to be connected to the HART maintenance software PC.
In addition, both backplanes have a facility to accept dual (redundant) power supplies for
maximum system availability.
MTL4850/54
Figure 2.4
HART CPH-SCxx
backplane
Figure 2.3
HART
connection unit
