Dwyer GFM4 - Manual (Page 13)

Command
Name
Flow
Temperature
Reading
Pressure
Reading
Gas Select
Auto Zero
Flow Alarms
Temperature
Alarms**
Pressure
Alarms
Relay Action
Description
Requests the current flow sensor
reading.
Requests the current temperature
sensor reading (** if supported by
hardware)
Requests the current pressure
sensor reading (**if supported by
hardware)
Selects one of the ten primary gas
calibration tables to use. Tables are
entered via the MEM commands at
time of calibration.
Starts/reads the status of the auto
zero feature (Note: The Z, N
command can be used only when
absolutely no flow takes place
through the meter. It can take
several minutes to complete. Unit
will not respond to other commands
when this is in progress.)
Sets/reads the status of gas flow
alarms.
Note: High and Low limits have to
be entered in the % FS. High alarm
value has to be more than Low
alarm value.
Alarm conditions:
Flow > High Limit = H
Flow < Low Limit = L
Low < Flow < High = N
Sets/reads the status of the
temperature alarms. Note: High
and Low limits have to be entered
in °C. High alarm value has to be
more than Low alarm value.
Alarm conditions:
Temp. > High Limit = H
Temp. > Low Limit = L
Low < Temp. < High = N
(**if supported by hardware)
Sets/reads the status of the
pressure alarms. Note: High and
Low limits have to be entered in
PSI; High alarm value has to be
more than Low alarm value.
Alarm conditions:
Temp. > High Limit = H
Temp. > Low Limit = L
Low < Temp. < High = N
(**if supported by hardware)
Assigns action of the two SPDT
relays. The coil is energized when
the condition specified by
“Argument 2” becomes true.
No.
1
2
3
4
5
6
7
8
9
Command
F
TR
PR
G
Z
FA
TA
PA
R
Argument 1
T (set gas table)
S (status)
N (do it now)
W (write zero to
EEPROM)
S (status while
auto zero in
progress)
V (display zero
value)
H (high flow limit)
L (low flow limit)
A (action delay in
seconds)
E (enable alarm)
D (disable alarm)*
R (read status)
S (read status)
H (high limit)
L (low limit)
E (enable alarm)
D (disable alarm)
R (read status)
S (set status)
H (high limit)
L (low limit)
E (enable alarm)
D (disable alarm)
R (read status)
S (set status)
1 (relay 1)
2 (relay 2)
Argument 3 Argument 4 Response
(Actual flow
in current engineering
units)
(Actual
temperature in current
engineering units)
(Actual
pressure in current
engineering units)
GTO through GT9
GSO through GS9
ZN
ZW (when done)
ZNI,while Z, N
is in progress
ZV,
AH
AL
AA
AE
AD
N (no alarm)
H (high alarm)
L (low alarm)
AS:M,L,H,D
TAH
TAL
TAE
TAD
N (no alarm)
H (high alarm)
L (low alarm)
TAS:M,L,H
PAH
PAL
PAE
PAD
N (no alarm)
H (high alarm)
L (low alarm)
PAS:M,L,H
RN
RT
RH
RL
RR
RA
RB
RC
RD
RxN, RxT, RxH, RxL,
RxR, RxA, RxB, RxD
Argument 2
0 (gas 0) to
9 (gas 9)
(0 to
3600 sec)
N (no action,
relay disabled)*
T (totalizer
reading > limit)
H (high flow
alarm)
L (low flow alarm)
R (range high &
low alarm)
A (high temp.)
B (low temp.)
C (high press.)
D (low press.)
S (status)
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