External Hart Devices (Slaves) - Emerson Rosemount 5402 Reference Manual

Reference Manual
00809-0100-4026, Rev KC
4.11.5

External HART devices (slaves)

The HMC supports up to four external HART devices. The external devices are separated by using the
HART address. The address must be different between the external devices and only addresses 1 to 5 are
allowed for multiple slaves. Connect the devices one at a time and change the short address prior to
connecting the next device by using a HART Configuration Tool such as RRM, or a Field Communicator.
Note
The power supply from the HMC to external HART devices is not intrinsically safe. In a hazardous
environment, any external HART device connected to the HMC must have Flameproof/Explosion-proof
certification.
The HMC cyclically polls the HART devices for measurement values. The update rate depends on the
number of connected devices and is shown in
Table 4-3. Approximate Update Rates for Measurement Values
Number of devices (slaves)
1
2
3
4
5
Figure 4-18. The HMC Module Supports up to Four External Devices (slaves)
Up to four
external
devices
Electrical Installation
Table
Approximate update rate
2 seconds
3 seconds
4 seconds
5 seconds
5 seconds
External HART
External HART
device 1
device 2
4-3.
RS-485
bus
HART to Modbus Converter
MB
MA
MODBUS
-
(RS-485)
- +
POWER
HART Ambients > 60 ºC
Use wiring rated
+
for min 90 ºC
Electrical Installation
October 2018
Power
supply
93