rotork Modbus - Motion Inhibit Timer (MIT) (Register 11); Auxiliary Input Mask (Register 12)

Input and Output Signals
Publication PUB091-004-00_0918 57 of 64
7.9.4 Motion Inhibit Timer (MIT) (Register 11)
The MIT setting is the period that must elapse between consecutive starts of the actuator motor when
in positioning mode. The time runs from when the motor stops until the next time it starts
The idle period will prevent the actuator motor from exceeding its rated number of starts per hour.
In addition, when tuning the valve positioner, the setting can be used to allow the plant dynamics to
stabilise between valve movements.
7.9.5 Auxiliary Input Mask (Register 12)
This parameter register allows the auxiliary inputs (open, stop, close, ESD) to be set to control the
actuator or simply to report their status. In addition, it allows the sense of the input (open or closed
contact) that is reported as true (1) to be set. Actuator control always requires a true (1) input signal.
The status of the inputs is always reported over the network and they can be used to report associated
plant inputs instead of controlling the actuator.
The register should be considered in its binary format using the low order byte. The number has the
binary form x
7
x
6
x
5
x
4
, y
3
y
2
y
1
y
0
, requiring 8 bits. Each bit in the high order nibble, x
7
x
6
x
5
x
4
, either enables
or disables the associated input for control of the actuator. The bits in the low order nibble, y
3
y
2
y
1
y
0
,
determine if the input reports a closed contact as a '1' or an open contact as a '1'. Only when the input
is a '1', as set by the mask, and the contact state is normally open will the actuator respond to the
input if it is also set to control the actuator.
To allow an input to act as a control signal, its associated bit in the high order nibble must be set to a
'1' in the mask. To allow a closed contact to be reported as a '1' then its associated bit in the low order
nibble must be set to '1' in the mask.
Bit
Position
Value
Function
7
X
7
0
Disable ESD input as command
1
Enable ESD input as command
6
X
6
0
Disable Stop/Maintain input as command
1
Enable Stop/Maintain input as command
5
X
5
0
Disable Close input as command
1
Enable Close input as command
4
X
4
0
Disable Open input as command
1
Enable Open input as command
3
Y
3
0
Report closed contact on ESD input as ‘0’
1
Report closed contact on ESD input as ‘1’
2
Y
2
0
Report closed contact on Stop/Maintain input as ‘0’
1
Report closed contact on Stop/Maintain input as ‘1’
1
Y
1
0
Report closed contact on Close input as’0’
1
Report closed contact on Close input as ‘1’
0
Y
0
0
Report closed contact on Open input as ‘0’
1
Report closed contact on Open input as ‘1’
The following examples show how the Auxiliary Input Mask settings can be applied.