www.miinet.com
Moore Industries-International, Inc.
- 122 -
User’s Manual
238-760-00K
May 2019
Functional Safety Dual Input Smart HART® Temperature Transmitter
STZ
SECTION 7
Action
1
Make sure that the loop can be shut down safely. Remove power and disconnect the STZ from
the loop and the sensor(s).
2
Check for isolation between input to output; check input and output to case, if case is metal.
Using an ohmmeter, measure the resistance between each input and output pin. Verify that the
measured resistance is greater than 1MΩ.
For HP and DIN units, measure the resistance between each pin and the case and verify that the
measured resistance is greater than 1MΩ.
3
Connect +/-PS terminals to 24Vdc supply, in series with a 250ohm, 0.01% resistor. Connect a
DVM (0.025% or better accuracy) across the resistor. Also connect across the resistor a HART
master or a HART monitor or a PC with HART modem and STZ DTM.
4
Connect sensor simulator(s) to the input terminals. These must reflect the actual instrument
configuration.
5
Apply power and check instrument response at 0%, 25%, 50% 75% and 100% of span. Verify that
the analog output is within 1% of expected value (i.e. 4, 8, 12, 16, 20mA). Also verify the PV
reading in HART and for the STZ HP, verify that the display reads correctly. Vary the loop supply
voltage and verify that the loop current is stable.
6
On the HART master, read the Device variables to check that the RJC Temperature reading is
within 5
o
C of the ambient temperature.
7
Open each sensor lead and verify that the broken wire (BW) response is correct. Reconnect the
lead and repeat for the next lead.
8
The STZ has been checked for actual configuration. If all results are satisfactory, it may be
reinstalled in the loop.
If the STZ is to be used in another application, configure it for that application and repeat the
above steps. If the STZ is to be kept as a spare, run the proof test after configuration for its next
use.
Step
Table 7.1
Proof Test Steps using STZ with HART