Future Design MCT-MC 4.3, User Manual

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MCT-MC
4.3
Configuring the MCT-MC - 31 - FDC MCT-MC
4.3.22 Output 4 Low/High Limit Values
The output low and high limit values can be set when the output 4 function is set for retransmit process or
setpoint value. They are used to set the minimum and maximum percentage of the output range for the installed
output type.
For example, the standard range of the mA output is 0-20mA. In order to use the output as a 4-20mA output,
the low limit value would need to be set to 20% (20% of 20ma = 4ma). For the voltage output, the default range
is 0-10Vdc. In order to achieve a 1-5Vdc output, the low limit would have to be set to 10% (10% of 10Vdc is
1Vdc). The high limit would then have to be set to 50% in order cut the output span in half to get a maximum
output of 5Vdc.
4.3.23 Output 4 Retransmit Low/High Scale
The output retransmit low and high scale can be set when the output 4 function is set for retransmit process or
setpoint value. They are used to set the retransmit range of the output. The low scale value corresponds to
the output low limit value and the high scale value corresponds with the output high limit value.
4.3.24 Alarm (1-3) Function
The Alarm 1, 2 and 3 Functions are used to select the alarm type for outputs 2, 3 and 4 respectively if the output
function is configured as alarm or reverse alarm. The alarm selections are mutually exclusive, i.e., selecting
one will turn off the others. Once the desired alarm type has been selected, press the “Done” button to set the
alarm function for the loop control board output and return to the main Loop Configuration screen.
NOTE: For the following alarm descriptions, PV = process value, SV = the control set point value, ASP is the
alarm set point and AHY is the alarm hysteresis.
A
Process high alarm is independent of set point. When the process value is higher than the alarm set point
(PV > ASP), a process high alarm occurs. When the process value is lower than the alarm set point minus the
alarm hysteresis (PV < ASP–AHY), the alarm is off.
A
Process low alarm is independent of set point. When the process value is lower than the alarm set point
(PV < ASP), a process low alarm occurs. When the process value is above the alarm set point plus the alarm
hysteresis (PV > ASP+AHY), the alarm is off.