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12
…8
COMMUNICATION
8.6
Command Mnemonics
8.6.1
General Parameters
Parameter
Mnemonic
Command
Reply Interpretation
Read
(R)
Write
(W)
Operating Parameters
Measured Variable
MV
Yes
No
Dependent on the programmed display range
Instrument Status
IS
Yes
No
Range 0 to 4095 – see Fig. 8.7 on page 10
Control Set Point
Value
SP
Yes
No
Any value within the programmed display range
Remote Set Point
Value
RP
Yes
No
Any value within the programmed display range
Dual Set Point Value
DU
Yes
Yes
Any value within the programmed display range
Control Output
OP
Yes
Yes
0 to 100.0 (%)
Manual Reset Value
MR
Yes
Yes
0.0 to 9.99 (%)
Actual Valve Position
VP
Yes
No
0.0 to 100.0 (%)
Auto/Manual State
AM
Yes
Yes
0 = AUTO
1 = MAN
Non-Volatile Save
State
NV
Yes
Yes
0 = disable
1 = enable
Power Fail
State/Acknowledge
PF
Yes
Yes
0 = Power failure acknowledge
1 = Power failure
Self-Tune Parameters
Self-Tune Type
TT
Yes
Yes
0 = Start Up
1 = At Set Point
Percentage Output
ZS
Yes
Yes
0.0 to 100.0 (%)
Step from Zero
Hysteresis Value
SY
Yes
Yes
0.1 to 10.0 (%)
High Limit
TH
Yes
Yes
Any value within the programmed display range
Low Limit
TL
Yes
Yes
Any value within the programmed display range
Self-tune Error State
TF
Yes
No
0 = No error/error acknowledged
1 = Process variable too close to set point
2 = Input too noisy
3 = Timer overflow
4 = Self-tune limits exceeded
5 = Maximum rate may not have been
detected
6 = Ratio of PV Amplitude/hysteresis < 4
7 = Proportional band or integral action time
P.I.D. Control Terms
TM
Yes
Yes
0 = P only
1 = P and I
2 = P, I and D
Control Type
TC
Yes
Yes
0 = Type A
1 = Type B
Self-tune Enable
ST
Yes
Yes
0 = Self-tuning off
1 = Self-tuning on
Advisory
Proportional Band
AP
Yes
No
0.1 to 999.9
Advisory Integral
Time
AI
Yes
No
1 to 7200 seconds, 7201 = OFF
0 to 120 minutes, 121 = OFF
Advisory Derivative
Time
AD
Yes
No
1 to 999.9 seconds, 0 = OFF
0.1 to 16.65 minutes, 0 = OFF
Self-tune Accept
SA
Yes
Yes
0 = Reject advisory values
1 = Accept advisory values