Tamron MST2000 operation manual Alarm Programming Information, Alarm ‘ENABLE’ Word Definition

OPERATION MANUAL ALARM PROGRAMMING INFORMATION

9. ALARM PROGRAMMING INFORMATION

9.1 Alarm ‘ENABLE’ Word Definition

The ALARM ‘ENABLE’ WORD (16 bit word) is divided into two 8 bit bytes. The lower order byte (bits 1 –

8)is used to enable and disable the alarm functions. The higher order byte (bits 9 – 16) is used to control how the alarm is displayed and/or output to the user interface. Some bits are currently undefined and reserved for future use.

BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT	BIT
16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
32768	16384	8192	4096	2048	1024	512	256	128	64	32	16	8	4	2	1

9.2 Low Byte ‘BIT’ Definitions

A.Under-range:Enabling the un der-range alarm bit will cause the under-range alarm to become ac- tive when the 4-20 milliamp output cur rent reaches 3.9 milliamps.

B.Over-range:Enabling the over-range alarm bit will cause the over-range alarm to become active when the 4-20 milliamp output current reaches 20.5 milliamps.

C.RTD Fault: Enabling the RTD fault alarm bit will cause the RTD fault alarm to become active if an open circuit or short circuit is sensed in the 4-wire RTD loop connection. See Section 9.3 G

D.ISO Comm error: Enabling the ISO Comm er ror alarm bit will cause the ISO Comm er ror alarm(s) to become active if any communication er rors or hard ware faults are de tected from any of the ex ter- nal 4-20 milliamp input boards. (ISO = Iso lated Out put Mod ule). See Sec tion 9.3 G.

E.Hardware Fault: Enabling the Hardware Fault error alarm bit will cause the Hardware Fault error alarm to become active if any internal hardware circuit faults (including microprocessor watchdog timer faults) are detected from the MST2000 internal circuitry.

þNote: For each alarm fault bit above, in di vid ual alarm sta tus bit(s) are pro vided in the ALARM STATUS word to iden tify which alarm is ac tive. Each alarm sta tus bit and the as so ci ated bi nary val ues are de scribed later in this section.

9.3High Byte ‘BIT’ Definitions

A.Fail-low:Enabling the Fail-low bit will cause the 4-20 milliamp output to change to the fault current value of 3.8 milliamps if any alarm is active.

B.Fail-high:Enabling the Fail-high bit will cause the 4-20 milliamp output to change to the fault current value of 21.0 milliamps if any alarm is active.

C.Last-val:Enabling the Last-val bit will cause the 4-20 milliamp output to hold at the last value if any alarm is active.

þNote:

&The user must insure that only one of the 3 fault current control bits is set for proper operation.

&When entering PROGRAM mode, the 4-20 milliamp output current will change to the fault current as set by the fault current control bits.

D.LCD Icon: Enabling the LCD Icon bit will cause the LCD ‘Alarm’ icon to be turned on if any alarm is active.

Brandt Instruments, Inc. MST2000 Multivariable SMARTFLOW ® Transmitter Page 19