5-244 N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUALTRANSDUCER INPUTS/OUTPUTS CHAPTER 5: SETTINGS5Hardware and software is provided to generate DCmA signals that allow interfacing with external equipment. Hardwaredetails are contained in chapter 3. The DCmA output channels are arranged in a manner similar to transducer input or CTand VT channels. The user configures individual channels with the settings as follows.The channels are arranged in sub-modules of two channels, numbered 1 through 8 from top to bottom. On power-up, therelay automatically generates configuration settings for every channel, based on the order code, in the same manner usedfor CTs and VTs. Each channel is assigned a slot letter followed by the row number, 1 through 8 inclusive, which is used asthe channel number.Both the output range and a signal driving a given output are user-programmable via the following settings menu (anexample for channel M5 is shown).The relay checks the driving signal (x in equations below) for the minimum and maximum limits, and subsequently re-scales so the limits defined as MIN VAL and MAX VAL match the output range of the hardware defined as RANGE. Thefollowing equation is applied:Eq. 5-25wherex is a driving signal specified by the SOURCE settingImin and I max are defined by the RANGE settingk is a scaling constant calculated as:Eq. 5-26The feature is intentionally inhibited if the MAX VAL and MIN VAL settings are entered incorrectly, for example when MAX VAL– MIN VAL < 0.1 pu. The resulting characteristic is illustrated in the following figure.Figure 5-123: DCmA output characteristicSettingsDCMA OUTPUT F1 SOURCE — This setting specifies an internal analog value to drive the analog output. Actual values(FlexAnalog parameters) such as power, current amplitude, voltage amplitude, power factor, etc. can be configured assources driving DCmA outputs. See Appendix A for a list of FlexAnalog parameters.DCMA OUTPUT F1 RANGE — This setting allows selection of the output range. Each DCmA channel can be set independentlyto work with different ranges. The three most commonly used output ranges are available.DCMA OUTPUT F1 MIN VAL — This setting allows setting the minimum limit for the signal that drives the output. This setting isused to control the mapping between an internal analog value and the output current. The setting is entered in per-unitvalues. The base units are defined in the same manner as the FlexElement base units.I outI min if x MIN VAL<I max if x MAX VAL>k x MIN VAL– I min+ otherwise=k I max I min–MAX VAL MIN VAL–--------------------------------------------=842739A1.CDRDRIVING SIGNALOUTPUT CURRENTMIN VALIminImaxMAX VAL
