300 Series Standard Special Features

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300 Series Controls standard 3 Inputs

  • #1 - Universal Thermcouple, RTD and Linear VDC/mA [18-Bit A/D] 
    • Thermocouple Types: J, K, T, B, E, R, S, C and Platinell II
    • RTD 100 ohm: DIN and JIS standards
    • Linear mA/VDC:
      • 0-20mA & 4-20mA
      • 0-1VDC, 0-5VDC, 1-5VDV & 0-10VDC
  •  #2 Current Transformer [CT] or linear VDC/mA. [18-Bit A/D]
    • CT Sensor input for 0-50A range.
    • Linear inputs can be configured as a 2nd PV or as remote SP.
      • As a 2nd PV it may configured as a PV or delta PV1/PV2
      • Alarms #1 and/or #2 may be asssigned to either input #1 and input #2
      • Input #1 or Input #2 may be assigned as the control's PV. As the PV it will be displayed and output #1 by default assigned as the control output.
  • #3 - Event input - dry contact input configurable to:
    • Change SP, PID, SP & PID,
    • Change local SP to Remote SP
    • Reset Latched alarms [C, 100, 300 & P Series alarms may be configured as latching or non-latching]
    • Disable Output #1, Output #2, Output #1 & #2.
    • Lock all Parameters - operator can view parameters but not change them including SP. Parameters are available to view & change via RS232/485 Modbus communication.

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High Accuracy 18-Bit A/D and 15 D/A Analog Input & Output

The C, 100, 300 & P Series Controls provide the highest A/D and D/A Analog Input & Output Resolution in the control industry.

Input Resolution is an important specification to a process control's performance & accuracy. FDC's 18 Bit A/D and 15 Bit D/A is the highest Input & Output resolution in the industry. Couple this to our 200 ms input scan and proprietary Fuzzy PID auto-tuning results in a high performance control with the industries lowest pricing.

Click here for more information on Input & Output Resolution.htm

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Display Configuration for Input #1 and Input #2

The Process Variable in the 300 Series Controls [300 Series has two analog & one event input] is configurable as one of the following:

  • PV1 [Input #1]
  • PV2 [Input #2]
  • PV1-PV2
  • PV2-PV1

The default display will show the Process Variable as configured above.

The Display Mode for the 300 Series also allows operator viewing of the following:

  • Process Variable [defined above], Input #1, Input #2, Historical Minimum & Maximum for Input #1 & #2, Percent Proportional output for Output #1 and #2, Deviation between SP & PV, PID values, and CJC Temperature value.

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Remote Setpoint

The 300 Series control platform has 3 inputs, two of which may be configured to accept a Remote Setpoint input:

  • Input #1 accepts T/C, RTD and linear mA/VDC.
  • Input #2 acceptes Current Transformer [CT] for a specific alarm function and linear mA/VDC.

Remote Setpoint Input: Input #1 and #2 can be configured to accept linear mA/VDC input as the PV or as a Remote Setpoint. When configured as a Remote Setpoint the other input is the PV input.

The Event input [input #3] may be configured to switch between local & remote setpoint.

Example Application - Multizone Oven: One 300 Series control [master] retransmits its' setpoint to other 300 Series controls [slaves] insuring each zone control has the same setpoint.

Note: When the SP ramp function is used, the lower display will show the current ramping value. However it will revert to show the set point value whether it is manual enter SP or Remote SP as soon as the up or down key is touched for adjustment. The ramping value is initiated to process value either power up or RAMP and /or set point are changed. Setting RAMP to zero means no ramp function at all.

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2nd Set Point & PID variables via Event Input

A 2nd Setpoint and/or PID variables may be selected using the event input available in the 300 Series Controls.  With the event input configured to change SP, PID or SP & PID, a dry contact signal applied to the event input terminals will drive the appropriate change.

The contact closure may come from external device or from an alarm input from the 300 Series Control. Examples with input coming from 300 Series Control:

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Sensor Break Alarm

  • Bumpless Transfer of Proportional Outputs
  • Configurable Proportional Output to a default value 0 - 100%

Bumpless Transfer with Sensor or other control Failure: [applicable to C, 100, 300 & P Series]

Upon Sensor or other control Failure the Proportional Outputs can be configured to provide a Bumpless Transfer of the current proportional output.

With the Bumpless Transfer configured and the process load does not change the process can continue to be controlled temporarily as if the sensor is normal. However, once the load changes the process may run away. Therefore you should not rely on bumpless transfer for any extended period of time. For fail safe reason an additinal alarm should be used to annuciate a system or sensor failure.

Control Outputs configured to a default output 0 - 100%: [applicable to C, 90, 200, 200, 300 & P Series Controls]

Upon Sensor or other control Failure the Proportional Outputs can be configured to default a configurable percent output ranging from 0% to 100%. Output #1 when set as an on-off control can be configured to be open or closed.

Note: Outputs configured as alarms are configurable to open or close on control failure. This feature is described in Alarm Logic page.

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Dwell Alarm - Reset via Power-up sequence or event input

Dwell Timer Alarm: [applicable to C, 90, 100, 200, 300 & P Series Controls]

One alarm may be configured as a dwell timer alarm. Once configured the dwell time is measured in minutes - the maximum number of minutes vary by control series with the longest being the 300 Series at 6,553 minutes.


Once the process reaches setpoint the dwell timers starts to count down from zero until time out. The dwell timer alarm relay will remain unchanged until time out.


The dwell timer is reset by power up sequence or the  event input may be configured to reset the dwell timer]


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2 Setpoint Ramp/One Soak Feature

Setpoint Ramp / Soak with Dwell Timer: [applicable to C, 90, 100, 200, & 300 Series Controls]

When controls are configured for Setpoint Ramp and an alarm as Dwell Timer a one Setpoint Ramp & Soak feature is available. When the control is powered the SP will ramp from existing PV at the configured rate to the control SP. Once SP is achieved the dwell timer will start its' countdown. When the dwell time is achieved the alarm relay will activate and if so wired to shut the system down or alert operator dwell (Soak) time is completed.

Two Setpoint Ramps with one Dwell Time: [applicable to 300 Series only] Click here for more information on the Series 300 Special Features.

The 300 Series controls with event input configured to change SP offers ability to have a 2nd SP Ramp. PID variables may also be changed when switching to SP2. See above Selection of 2nd Setpoint and/or PID Variables.

Above shows 300 Series using Dwell Timer alarm to switch to 2nd SP

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Cascade & Differentail Control Applications

Differential Control: In certain applications it is desirable to control a second process such that its process value always deviates from the first process with a constant value.


The 300 Series allows the Control & Display to be configured independenlty as PV #1, PV #2,  PV1-PV2 or PV2-PVI.


For Differential Control Configure the appropriate PV's as PV1 & PV2, configure control as either PV1-PV2 or PV2-PV1 and the control output will function to maintain set differential between the two.


The PV display is configured seperatly from the control and can be set at PV1, PV2, PV1-PV2 or PV2-PV1.


Cascade Control- The output of control #1 becomes control #2 SP. Cascade Control requies two controls.

Control #1 has retransmission option configured as to retransmit output #1 % Output. Control #2 accepts Control #1 retransmitted output as its' Remote Setpoint.

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View CJC Temperature Values

Cold Junction Compensation [CJC] Temperature Value:

The CJC is used with thermocouple [t/c] inputs to measure the ambient temperature where the t/c's connect to the control and may be viewed at any time. The CJC value is not used by the control when configured for RTD or Linear mA/VDC inputs but may still be viewed. As the CJC value represents the temperature at the control's terminal block [slightly higher than ambient due to heat generated by controller operation] the CJC value may be of interest if the temperature of the panel box the control is mounted is of interest.

Via RS485/232 Modbus - Read Historical Minimum & Maximum PV Values and CJC Temperatures: [applicable to C, L, 100, 300 & P Series Controls.

The subject values have Modbus addresses and can be read via RS232/485 communications.

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Future Design Controls: 888.751.5444  csr@futuredesigncontrols.com