Application and Installation Guide EMCP 4 SCADA Data Links
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Bytes 1-11: ASCII data, characters 0x30 through 0x5A valid (numbers and capital letters). String
terminates with a NULL character (0x00).
Example: Reading the Control Serial Number would return the following:
0x 0A33 3438 3942 3031 3654 5800
7.7 READING AND SETTING VOLTAGE BIAS
This example demonstrates the data link commands to read setpoints, read registers, and write to registers.
Furthermore, it illustrates the functionality of integration with an external Automatic Voltage Regulator.
Check the Maximum Generator Voltage Output Bias Percentage setpoint (via the EMCP 4 display, or using
ET). For this example, assume that the Maximum Generator Voltage Output Bias Percentage is 20%. Read
the Total Voltage Bias Percent and the Desired Genset Output Voltage before any bias is applied.
Request: 0x 01 03 04 21 00 01 xx xx
0x 01 = slave address of EMCP 4
0x 03 = function code (Read Registers)
0x 04 21 = Total Voltage Bias Percent
0x 00 01 = 1 = register count
Response: 0x 01 03 02 7D 80 xx xx
0x 02 = byte count (2 bytes = 1 register)
0x 7D 80 32128 251% (-251% offset) 0.0% bias
Request: 0x 01 03 04 20 00 01 xx xx
0x 01 = slave address of EMCP 4
0x 03 = function code (Read Registers)
0x 04 20 = Desired Genset Output Voltage
0x 00 01 = register count
Response: 0x 01 03 02 01 E0 xx xx
0x 02 = byte count (2 bytes = 1 register)
0x 01 E0 480V desired
To adjust the voltage, navigate to the Control menu and press the up arrow ten times, re-read the Total
Voltage Bias Percent register.
Request: 0x 01 03 04 21 00 01 xx xx
0x 01 = slave address of EMCP 4
0x 03 = function code (Read Registers)
0x 04 21 = Total Voltage Bias Percent
0x 00 01 = register count
Response: 0x 01 03 02 80 00 xx xx
0x 02 = byte count (2 bytes = 1 register)
0x 80 00 32768 256% (-251% offset) 5.0% bias
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