COSA Xentaur Xentaur HDT - Manual (Page 25)

HDT User’s Manual
page 18
Note: ‡ in the factory default mode the HDT is setup using HART Alarm Selection Code
(ref Universal command 15) such that when there are errors the current loop draws 21mA.
However it is also possible to configure it to 4mA, or 20mA, or 3.8mA, or to hold last out-
put
Symptom
(more than 25 sec after powerup)
Possible cause Remedy
Current
Loop
Pin 3
Fixed at
~3.8mA
High
impedance
Instrument failure
Cycle power, if prob-
lem persists return
instrument
EEPROM checksum
failure
Intermittent
(0V-3V)
1200 baud
RS-232 data
Loop voltage insuffi-
cient
Check power supply's
capability to maintain
at least 5V at 20 mA.
see appendix A
Fixed at
21mA
‡
1. open sensor
2. shorted sensor
Check sensor & cycle
power, if problem per-
sists return instrument
4 to 20 mA Normal Operation
Fixed at
4mA
Measurement below
HART Command 15
Primary Variable Ana-
log Output Lower
Range
Refer to sensor section
XXX
Fixed at
20mA
Measurement above
HART Command 15
Primary Variable Ana-
log Output Upper
Range
0 mA
High
impedance
1. Cable open
2. Fuse open due to
excessive voltage 1. Check cables
2. Wait for self reset-
ting fuse cooldown.