5.
Determine any non-linear voltage drops due to the barrier (Vbarrier) from the barrier
data sheet (for example, voltage drops due to diodes).
6.
Calculate Vworking = Vsupply – Vbarrier.
7.
Using Vworking and Rworking, confirm that operation is within the shaded area of
the graph Loop Voltage versus Loop Resistance on page 88.
Notes:
• The following list is not complete: there are many safety barriers on the market,
which will work with the SITRANS Probe LU.
• The barriers listed below have all been tested and are functionally compatible with
the SITRANS Probe LU.
• The barriers listed below are all HART compatible.
PLC Input Modules
Manufacturer
Siemens
Passive Shunt Diode Barriers
Note:
A well regulated supply voltage is required.
Manufacturer
MTL
MTL
Stahl
Stahl
Active barriers (repeating barriers)
Manufacturer
Siemens
MTL
MTL
Stahl
7ML19985HT01
SITRANS Probe LU – INSTRUCTION MANUAL
Part Number
SM331 PCS7 HART Input Module
Part Number
787SP+ (Dual channel)
7787P+ (Dual channel)
9001/01-280-100-10 (Single channel)
9002/01-280-110-10 (Dual channel)
Part Number
7NG4122-1AA10
706
7206
9001/51-280-110-14
Page 89