Precision Digital PD570 - Manual (Page 18)

This parameter establishes the set point for limit operation. This is the value set as the
operating limit that will trigger the latching limit control relay. The parameter HI.LO sets if
this is a high limit or a low limit.
5.2 Control Group (G.CTL)
Press SET/ENT key to select control group. (Refer to parameter map in section 3.)
PV
This parameter established the set point as a high or low limit value. If set as a high limit,
the unit will consider the input beyond the set limit when PV > SP. If set as a low limit, the
unit will consider the input beyond the set limit when PV < SP.
This parameter determines the status of the latching relay (OUT1) when the unit is turned
on. If R.MD is set as ON, the output condition will be a function the PV and SP as normal.
If OFF, the output will enter over limit condition until reset. To set the condition of the relay
in normal a nd over limit conditions, refer to parameter O.ACT below.
PV
PV
PV
Turning ON this parameter locks all other settings from being changed. This applies to
the operation display functions, such as changing the set point, as well as setting group
parameters. The default setting is OFF.
This parameter establishes the password for the controller. This password must be
entered at the PWD screen before accessing the control group (G.CTL) or it will not
access the settin g groups after the PWD prompt. The default setting is "0". See the
parameter map in section 3 for the location of the PWD prompt in the group menus. PV
PV
Be sure not to forget the password once it has been set. If the password is forgotten, contact
technical support as listed on the back of this manual. !
CAUTION
This parameter sets the operatio n for the limit control latching relay (OUT1). In reverse
(failsafe) operation, the co ntrol relay is energized during normal conditions. In forward
operation, the control relay is energized during over limit conditions. The default setting is
REV. See Fig 3 and 4 for a illustration showing reverse and forward operation.
PV
This parameter sets a high limit on what the set points can be programmed or changed to.
This value may reset if the type of input is changed, or if parameter IN.RH or IN.RL
(IN. SH or IN.SL if input type is mV or V) is changed.
This parameter sets a low limit on what the set points can be programmed or changed to.
This value may reset if the type of input is changed, or if parameter IN.RH or IN.RL
(IN. SH or IN.SL if input type is mV or V) are changed.
PV
PV
This parameter sets the hysteresis for the limit control. When returned within the limit
range after being over the set limit, this is an additional amount below the limit that the PV
must reach before the latching relay can be reset and the OVER LED turns off.
PV
PWD
Q G.CTL Q G.IN
K R
G.COM
Q G.RET Q G.ALM
ST ST
ST ST
ST T
PD570 Series Nova Process and Temperature Limit Controller Instruction Manual
18