Red Lion PCU - Manual (Page 56)

SENDING COMMANDS AND DATA (Cont’d)
VALUE
IDENTIFIER
DESCRIPTION
SERIAL
MNEMONIC
UNITS
A Input Display Value INP U
B Setpoint SET U
C Output Power PWR %
D Proportional Band PBD %
E Integral Time INT S
F Derivative Time DER S
G Alarm 1 AL1 U
H Alarm 2 AL2 U
I Deviation DEV U
J Output Power Offset OFP %
K Setpoint Ramp Rate RMP R
L Relative Gain CRG G
M Deadband CDB U
O Remote Setpoint Ratio RAT R
Q Remote Setpoint Bias BIA U
S Controller Mode 1 -Automatic
2 - Manual
(User)
U Setpoint Mode 1 – Local
2 - Remote
W Output status* OST U
X Secondary Proportional Band PB2 %
Y Secondary Integral Time IT2 S
Z Secondary Derivative Time DT2 S
AA Second Input Reading IN2 U
BB Remote Setpoint Reading or
Secondary Directed Setpoint RSP or
SP2 U
Output status transmission format = ABCD (0 = output off, 1 = output on)
Note: The % output power can be changed only if the controller is in the manual
mode of operation.
* The output status indicates the status of the controller’s outputs. The status can
only be read (see the following table). The alarms outputs may be reset by the
reset operator(R).
Output Status
NON-VALVE POSITIONER MODELS VALVE POSITIONER MODELS
A = Main output (OP1) A = Alarm 1 output(AL1)
B = Secondary output (OP2) B = 0
C = Alarm 2 output (AL2) C = Motor close output(CLS)
D = Alarm 1 output (AL1) D = Motor open output(OPN)
Example:
OP1 = ON, OP2 = OFF, AL2 = OFF, AL1 = ON
Transmission = “ OST 1001”
Note: The % output power can be changed only if the controller is in the
manual mode of operation.
The command string is constructed by using a command, a value
identifier, and a data value if required. The Data value need not contain the
decimal point since it is fixed within the unit, when programmed at the
front panel. The PCU accepts the decimal point, however it does not
interpret them in any way. Leading zeros can be eliminated, but all trailing
zeros must be present.
Example: If an alarm value of 750.0 is to be sent, the data value can be
transmitted as 750.0 or 7500. If a 750 is transmitted, the alarm value
changes to 75.0 in the unit.
The address command allows a transmission string to be directed to a
specific unit on the serial communications line. When the unit address is
z e r o , t r a n s m i s s i o n o f t h e a d d r e s s c o m m a n d i s n o t r e q u i r e d . F o r
applications that require several units, it is recommended that each unit on
the line be assigned a specific address.
If they are assigned the same address, a Transmit Value Command causes
all the units to respond simultaneously, resulting in a communication
collision. The command string is constructed in a specific logical
sequence. The PCU does not accept command strings that do not follow
this sequence. Only one operation can be performed per command string.
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